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Female Common Eider plumages in the western Atlantic

by Guillermo Rodríguez

Eiders have been a recurring topic of Birding Frontiers, and Martin really pushed the boundaries of Eider subspecies identification. However, most of the effort so far has focused on males, and females have gone largely forgotten. It’s time to change that! Along the East Coast of North America, where at least 2 subspecies regularly occur (the local breeder Dresser’s Eider S. m. dresseri and the arctic Northern Eider S. m. borealis), identification of females is relatively easy, and studying them here is useful for understanding the phenotypic variation. Massachusetts hosts tens of thousands of wintering Dresser’s, and in a few spots they are very close to shore, allowing great opportunities for study.

Given that both subspecies have been recorded in Europe, but only/mainly in adult male plumage, it’s interesting to take a look at some females to raise awareness about how distinctive these birds are. As far as I know, the plumage variation of borealis is poorly known due to lack of information from the breeding grounds, so this post contains a lot of speculation!

Dresser’s Eider dresseri

dresseri is the default subspecies in the US and southern Canada, with an extensive intergradation zone with borealis along the Labrador Peninsula. There are several features that differ from both borealis and mollisima, and identification might be possible in most individuals.

Bill lobe: reminiscent of the massive bill of males, female dresseri show very long lobes, almost reaching the eye, which often look thick and always present a blunt and rounded tip. If seen close enough, the pattern of the tip is absolutely diagnostic in almost all birds, and even at long distances they give a characteristic look. There is a huge variability in lobe length and thickness, apparently without correlation to age or geography.

Nostril position: as in mollisima, nearly all individuals show overlap of the nostril with the feathering at the bill base.

Bill color: dark blue, with a reduced and contrasting greenish tip, duller in first-winter birds. On average they have a small nail.

Head shape: typically flat-topped, with the forehead relatively short leading to a profile that is dominated by the straight contour of the large bill. My impression is that the crown is longer and the bill is shorter than in mollisima, leading to a more square-looking head, as opposed to the elongated bill (and consequently profile) typical of mollisima.

Plumage coloration: adult females are typically rusty or orange-tinged, with most first-winter females being browner and darker. Nevertheless, variation is extensive and adults vary from dark brown to creamy pale, whereas first-winter birds sometimes look very reddish and adult-like even in the first prebasic plumage. The cheek is often neat, lacking any dark streaking.

Tertials: richly colored in adults, typically with a rufous fringe and darker feather center, but the pattern is quite variable and sometimes they show vermiculated or almost entirely rufous tertials. Plain brown in juvenile and second-winter plumages.

Sails: some adult females show small black scapular sails, not as large as in adult males but definitely distinctive if present, compared to mollisima.

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Dresser’s Eider, adult female. Massachusetts, February 2017. Picture by Guillermo Rodríguez

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Dresser’s Eider, adult female. Massachusetts, February 2017. Picture by Guillermo Rodríguez

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Dresser’s Eider, female. Massachusetts, February 2017. Picture by Guillermo Rodríguez

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Dresser’s Eider, first winter female. Massachusetts, December 2016. Picture by Guillermo Rodríguez

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Dresser’s Eider, first winter female. Massachusetts, December 2016. Picture by Guillermo Rodríguez

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Dresser’s Eider, first winter female. Massachusetts, December 2016. Picture by Guillermo Rodríguez

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Dresser’s Eider, first winter female. Massachusetts, December 2016. Picture by Guillermo Rodríguez

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Dresser’s Eider, females. Massachusetts, January 2017. Picture by Guillermo Rodríguez. Note extensive color variation even in adult females

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Dresser’s Eider, females. Massachusetts, January 2017. Picture by Guillermo Rodríguez.

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Dresser’s Eider, adult female. Massachusetts, January 2017. Picture by Guillermo Rodríguez.

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Common Eider ssp, adult female. Massachusetts, December 2016. Picture by Guillermo Rodríguez. Interesting bird, very dresseri-like in plumage but showing pointed lobes. Likely an intergrade dresseri/borealis ?

Northern Eider borealis

Nearctic borealis overwinters around Greenland, reaching Newfoundland but quite rare further south (see below). I have experience only with vagrants in Massachusetts, but Bruce Mactavish kindly allowed me to study and show here some of his pictures from Newfoundland. Males from Newfoundland show orange bill but rounded lobe tips, likely suggesting these birds are relatively southern breeders in Greenland, as the high Arctic breeders are expected to show more pointed lobes.

Bill lobe: short and sharply pointed, and thus very different from dresseri, but probably not very distinctive if compared to mollisima.

Bill color: extensive pale greenish tip, sometimes with a more gradual transition towards the dark blue of the lobe. They often present a marked and pointed nail.

Nostril position: often no overlap of the nostril with the bill feathering, but there is definitely some variation and birds showing overlap aren’t rare.

Head shape: the bill height is very short in borealis, sometimes strikingly so, giving rise to a peculiar head shape. The triangular bill meets the rounded head forming a marked angle and leading to a usually concave head profile. In addition, the bill is remarkably short, especially the distance from the bill feathering to the bill tip – this feature is sometimes quite eye-catching.

Plumage coloration: it seems that birds overwintering in Newfoundland present two main “morphs” – rufous and pale grey – with all sort of intermediates. Whether this difference in plumage coloration is due to some geographical variation or just represents the plumage variation within a single population is yet unresolved. The fact that the few available pictures from N Greenland show completely grey females – whereas dresseri is usually reddish – suggests to me a clinal variation, but with the current evidence it’s difficult to say.

Wing bars: as in all other Common Eider subspecies, adult females present white tips on greater coverts and secondaries, forming two parallel white bards in the wing. This feature is in general quite variable, but in borealis the bars seem to be on average thicker and more obvious than in dresseri and mollisima.

Tertials: usually dull brown, or with at most rufous on the fringes.

Sails: pictures from Newfoundland don’t show obvious sails in females, but see below.

Note that most/all individuals shown here are adults: juvenile borealis seem to be quite rare, or at least in much lower proportion in the population than in dresseri, perhaps as a consequence of strong hunting pressure in Greenland & Canada?

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Northern Eider, adults. Newfoundland, March 2010. Picture by Bruce Mactavish.

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Northern Eider, adults. Newfoundland, March 2010. Picture by Bruce Mactavish.

Out of range borealis – some examples from Massachusetts

Borealis is scarce or rare on the East Coast of the US, with most accepted records involving adult males. However, females seem to be more regular, and given the striking differences in lobe pattern and overall coloration, they are much easier to separate from the local form than in Europe, where the similarity with mollisima hinders finding vagrant borealis. But certainly they are out there; several females have been claimed alongside confirmed males in the UK.

Among flocks of dresseri, female borealis look slightly smaller and less bulky. The measurements given in the Reever guide also suggest a smaller size compared to mollisima (but may depend on the population).  Most of the females seen in Massachusetts are of the striking pale grey morph, but it’s likely the proportion is also biased because they are the easiest to pick out from a distance. All five of the birds I’ve seen had neat pale cheeks and a distinctive pale eyebrow.

The bird below is a rufous adult female, quite similar to many of the birds from Newfoundland. Both the lobe length and the bill are fairly short, giving her a distinctive appearance.

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Northern Eider, adult female. Massachusetts, January 2017. Picture by Guillermo Rodríguez.

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Northern Eider, adult female. Massachusetts, January 2017. Picture by Guillermo Rodríguez.

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Northern Eider, adult female. Massachusetts, January 2017. Picture by Guillermo Rodríguez.

This second bird is a more typical pale grey/creamy adult female. Note all the key characters – pointed lobe, extensive pale bill tip, clean cheek, pale eyebrow, dull tertials, and hint of sails.

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Northern Eider, adult female. Massachusetts, February 2017. Picture by Guillermo Rodríguez.

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Northern Eider, adult female. Massachusetts, February 2017. Picture by Guillermo Rodríguez.

Some of the females seen in Massachusetts and neighbouring states are very striking. Too striking, perhaps. For instance, take a look at this amazing bird found by Marshall Illiff and Ryan Schain off Cape Cod, MA, on December 2011. This adult female differs from the typical borealis from Newfoundland and other vagrants seen in Massachusetts – note the heavy head, flat crown, large size, and even the shape and length of the lobe. Is it possible that this bird shows some influence from sedentaria, the subspecies that breeds in the Hudson Bay and spends the winter in polynyas in the frozen sea? Very little is known about this subspecies, not to mention the potential intergradation with borealis at Baffin Island and its surroundings. Do some birds from this region actually take the eastern route and spread out into the western Atlantic? Hopefully we will discover more about this fascinating topic in the future!

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Northern-type Eider, adult female. Massachusetts, December 2011. Picture by Ryan Schain.

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Northern-type Eider, adult female. Massachusetts, December 2011. Picture by Ryan Schain.

I would like to thank Bruce Mactavish and Marshall Illiff for insightful discussion about nearctic eiders.

Monteiro’s Storm-petrel, August 2013 (Richard Bonser). Note the active wing moult, with the inner primaries dropped.

Monteiro’s Petrel and Pelagic Birding off the Azores

By Peter Alfrey and Richard Bonser

The nine Azorean islands straggle 370 miles of the deep Atlantic, thrusting up from the deep oceanic depths as some of the tallest mountains on earth. The surrounding ocean, through its subsequent varied topography and numerous upwellings, provides rich feeding grounds for migrant seabirds as well as an Azorean endemic species, Monteiro’s Storm-petrel. The aim of this article is to chart the development of pelagic birding in the Azores, along with the species recorded to date, inviting you to consider joining a pelagic expedition.

Pelagic Birding exploration begins

In 2007, Peter Alfrey and Simon Buckell commenced a serious of exploration trips in the waters off the Azores in search of vagrant seabirds. There had already been a few interesting seabird sightings, mainly from the whale-watching boats around the islands – including Black-browed Albatross, Black-capped and Trindade Petrels – and so there was evidently some worth in inaugurating specific trips for seabirds.  The first trips were ‘wild cat’ expeditions from various islands including Corvo, Faial and Santa Maria with seamounts, banks and steep oceanic slopes targeted as likely areas of upwelling of nutrient rich waters, concentrating seabirds.

These first trips discovered good numbers of Wilson’s Storm-petrel, with 30+ at the Azores Bank off Faial in July 2007 and 70-80 also there in September 2009. Regular breeding species were also encountered, including Barolo Shearwater, Bulwer’s Petrels and Grant’s [Band-rumped] Storm-petrels (the winter breeding population), with a new breeding colony of the latter species discovered on Lagoinhas Islet off Santa Maria. Additionally, two Fea’s-type Petrel were recorded but overall, there was not much too significant to write home about.

Various forms of chums were experimented with, and in the end an adapted version of Hadoram Shirihai’s ‘petrel liquor’ was the most successful (using liquid oil instead of melted margarine), along with sardine chum, drip lines and fish oils. Experiments with frozen blocks proved problematic due to the comparatively warm deep Atlantic temperature.

Monteiro’s Storm-petrel- the discovery of a cryptic species endemic to the Azores

In 2008 the ground-breaking paper “Monteiro’s Storm Petrel Oceanodroma monteiroi: a new species from the Azores” by Mark Bolton et al was published in Ibis.  Significantly, this described the summer-breeding population of Band-rumped Storm-petrel on the Azores – Monteiro’s Storm-petrel – as having evolved separately from the winter-breeding population, as already suggested by Monteiro and Furness 1998. Additionally, subtle differences in biometrics, genetics, breeding ecology and vocalisations (Robb et al. 2008) were described, though to the field birder it’s extremely similar to other members of the Band-rumped Storm-petrel complex (see Flood and Fisher 2013, and Howell et al. 2010).

However due to the two populations breeding at different times of year, and with neither apparently spending their respective non-breeding seasons in Azorean waters, the initial way to see Monteiro’s Storm-petrel was simple – visit a colony at the right time of year when only that species was present; May to June in the case of Monteiro’s Storm-petrel. Opportunities for birders to encounter this cryptic species were limited by access restrictions to the main breeding colony off Praia Islet on Graciosa. Joining research teams, who monitored the artificially created nest burrows, used to be the only way. Richard Bonser was lucky to do this in July 2009, courtesy of Joël Bried, and was able to study the species at close range, including adults and nestlings. Remarkably, the two populations use the same nests at times – just as the Monteiro’s Storm-petrels were fledging and leaving their nest sites, the winter population of Band-rumped Storm-petrel (referred to from here on in as Grant’s Storm-petrel) were moving back in.

Monteiro’s Storm-petrel breeding burrows on Praia islet, July 2009 (Richard Bonser)

Monteiro’s Storm-petrel breeding burrows on Praia islet, July 2009 (Richard Bonser)

Monteiro’s Storm-petrel chick, August 2009 (Richard Bonser)

Monteiro’s Storm-petrel chick, August 2009 (Richard Bonser)

And so the waters around Graciosa were the obvious area for pelagic exploration to discover regular feeding areas to see Monteiro’s Storm-petrels at sea. It didn’t take long – in fact, it happened even before the description of the species – as in May 2007, Killian Mullarney and Magnus Robb not only discovered Monteiro’s Storm-petrel at sea to the southeast of Graciosa but also jammed in on a Black-capped Petrel! With a renewed sense of purpose, Peter Alfrey returned to the Azores for seabirding and visited Graciosa in May 2010.

Surveying the sea for Monteiro’s Storm-petrel

Peter Alfrey returned to Graciosa in May 2010, armed with GPS co-ordinates supplied by Killian Mullarney, but adverse weather hampered the potential for any prolonged period at sea. However, in limited searching, Monteiro’s Storm-petrels were found in the same area as in May 2007 and the peaks and troughs of the stormy sea also allowed close approach on a Barolo Shearwater – different from the usual view of a bird flapping frantically away ahead of a boat!

Barolo Shearwater, off Graciosa, May 2010 (Peter Alfrey)

Barolo Shearwater, off Graciosa, May 2010 (Peter Alfrey)

However, other than this close encounter, 2010 was pretty much a mini-disaster. It was getting very expensive too and with boat charter at over 500 euros per day, the only way to make these expeditions cost effective was to literally get more people on board. And so Peter Alfrey returned in June 2011 with a group of 12 birders (including Richard Bonser). However, on the first evening’s pelagic, Peter accidentally dropped £3,000 worth of camera equipment overboard which went straight to the bottom of abyss – negating any perceived cost saving!

The weather conditions in June 2011 were ideal for sailing, but this seemed to have changed the behaviour of the Monteiro’s Storm-petrels. Not many birds could be found in close proximity to the breeding area on Praia islet, and therefore a target area (a bank where fishermen had reported lots of small black and white birds) was visited – the Bank of Fortune – on the last day of the trip. Lying 20 or so miles to the east of Graciosa and providing numerous upwellings suitable for feeding seabirds, it was still within easy reach. Within a few hours of observation, we came across 50+ Monteiro’s Storm-petrels and up to 15 Wilson’s Storm-petrels all at close range.  We also saw at least three Barolo Shearwaters, a Grey Phalarope and four Great Skuas, surprisingly lingering in Azorean waters in early summer. Additionally, a Sooty Tern was also seen on Praia islet where up to two birds have been seen each year recently. That year we also had a Portuguese wildlife film-making crew with us that were filming for a documentary called ‘In Search of Monteiro’s Storm-petrel’, that has subsequently been watched by a quarter of million Portuguese. Not a bad thing for raising the profile of this Azores’ endemic and conserving its breeding habitat.

Monteiro’s Storm-petrel, June 2011 (Gareth Knass). During early summer these hot season breeders are the only ‘band-rumped storm-petrels’ present; the adults show no sign of moult on the primaries and secondaries.

Monteiro’s Storm-petrel, June 2011 (Gareth Knass). During early summer these hot season breeders are the only ‘band-rumped storm-petrels’ present; the adults show no sign of moult on the primaries and secondaries.

Adult Monteiro’s Petrel, June 2011 (Rafael Armada). This is a ‘classic’ Monteiro’s Petrel, photographed in mid-summer when only this species is present in the region, showing a deep forked tail and long-winged appearance producing an overall ‘rakish’ structure. The measurements of Monteiro’s Petrel indicate overall a longer wing and deeper fork to the tail than ‘Grant’s Petrel’.

Adult Monteiro’s Petrel, June 2011 (Rafael Armada). This is a ‘classic’ Monteiro’s Petrel, photographed in mid-summer when only this species is present in the region, showing a deep forked tail and long-winged appearance producing an overall ‘rakish’ structure. The measurements of Monteiro’s Petrel indicate overall a longer wing and deeper fork to the tail than ‘Grant’s Petrel’.

Adult Monteiro’s Petrel, June 2011 (Rafael Armada). Another view of a classic looking bird at the ‘right’ time of year in the ‘right ‘area.

Adult Monteiro’s Petrel, June 2011 (Rafael Armada). Another view of a classic looking bird at the ‘right’ time of year in the ‘right ‘area.

The Bank of Fortune

The last day of our June 2011 pelagic trip established one thing that has become integral going forwards. The Bank of Fortune was the place to locate storm-petrels at sea off the coast of Graciosa. With the world population of Monteiro’s Storm-petrel conservatively estimated at 250 birds, and all of these breeding off Graciosa, the draw of guaranteed sightings of this species would inevitably develop interest from birders. But there was more to come, and we wanted to hit this seabird hotspot at times where we could maximise chances of connecting with vagrants and passage seabirds too.

The obvious choice was to go in the August/September period – the overlap time of year between the hot and cool season breeding ‘band-rumped storm-petrels’, allowing both Monteiro’s and Grant’s Storm-petrels to be seen together. As well as trying to identify these two cryptic species at sea on the basis of wing moult, there was also the real potential of vagrant seabirds…

Monteiro’s Storm-petrel, August 2012 (Peter Alfrey). A worn bird in the start of its primary moult. The upperwing-coverts and dishevelled carpal bar also indicate this bird is in worn plumage.

Monteiro’s Storm-petrel, August 2012 (Peter Alfrey). A worn bird in the start of its primary moult. The upperwing-coverts and dishevelled carpal bar also indicate this bird is in worn plumage.

Monteiro’s Storm-petrel, August 2013 (Richard Bonser). Note the active wing moult, with the inner primaries dropped.

Monteiro’s Storm-petrel, August 2013 (Richard Bonser). Note the active wing moult, with the inner primaries dropped.

Monteiro’s Storm-petrel, August 2012 (Peter Alfrey). Early August is generally too early for Grant’s Storm-petrels to be prospecting nest burrows. However, some Monteiro’s Storm-petrels have also not started to undergo wing moult and therefore both species may show ‘a full set of wings’. In instances such as this, the brownness of the feathering – created by bleaching - suggests a warm season breeder.

Monteiro’s Storm-petrel, August 2012 (Peter Alfrey). Early August is generally too early for Grant’s Storm-petrels to be prospecting nest burrows. However, some Monteiro’s Storm-petrels have also not started to undergo wing moult and therefore both species may show ‘a full set of wings’. In instances such as this, the brownness of the feathering – created by bleaching – suggests a warm season breeder.

‘band-rumped storm-petrel’ off Graciosa, early August 2012 (Vincent Legrand). The fresh set of primaries and secondaries indicates this is either a juvenile Monteiro’s Storm-petrel or an early adult Grant’s Storm-petrel. Such birds cannot be identified with certainty on current knowledge, and despite perceived structural differences such as the less notched tail and sturdier overall appearance for Grant’s Storm-petrel, a bird such as this is best left unidentified.

‘band-rumped storm-petrel’ off Graciosa, early August 2012 (Vincent Legrand). The fresh set of primaries and secondaries indicates this is either a juvenile Monteiro’s Storm-petrel or an early adult Grant’s Storm-petrel. Such birds cannot be identified with certainty on current knowledge, and despite perceived structural differences such as the less notched tail and sturdier overall appearance for Grant’s Storm-petrel, a bird such as this is best left unidentified.

‘band-rumped storm-petrel’ off Graciosa, early August 2012 (Vincent Legrand). Grant’s Storm-petrels are on average more square-tailed than Monteiro’s Storm-petrel. However, Flood and Fisher (2011) advise to exercise extreme caution as there is much overlap in this feature between taxa. This problem is accentuated in judging these features in field conditions by apparent variation caused by angle of view and posture of bird which is further complicated in varying weather conditions. The shape of the tail is best assessed on square-on photographs and the presence of a deep fork is a stronger feature than an apparent square ended tail, which could be a result of feathers being splayed.

‘band-rumped storm-petrel’ off Graciosa, early August 2012 (Vincent Legrand). Grant’s Storm-petrels are on average more square-tailed than Monteiro’s Storm-petrel. However, Flood and Fisher (2011) advise to exercise extreme caution as there is much overlap in this feature between taxa. This problem is accentuated in judging these features in field conditions by apparent variation caused by angle of view and posture of bird which is further complicated in varying weather conditions. The shape of the tail is best assessed on square-on photographs and the presence of a deep fork is a stronger feature than an apparent square ended tail, which could be a result of feathers being splayed.

Adult Monteiro’s Storm-petrel, August 2012 (Vincent Legrand). Other summer breeding ‘band-rumped storm-petrels’ from Madeira and Cape Verde would also be moulting inner primaries during the late summer, and as such, these birds would be ‘impossible’ in some cases to tell from Monteiro’s Storm-petrel. A Madeiran Storm-petrel was actually sound recorded from within the Monteiro’s colony on Graciosa in May 2007 (Robb et al 2008) so this potential identification hazard is proven. Monteiro’s Storm-petrel is not called a ‘cryptic species’ for no reason!

Adult Monteiro’s Storm-petrel, August 2012 (Vincent Legrand). Other summer breeding ‘band-rumped storm-petrels’ from Madeira and Cape Verde would also be moulting inner primaries during the late summer, and as such, these birds would be ‘impossible’ in some cases to tell from Monteiro’s Storm-petrel. A Madeiran Storm-petrel was actually sound recorded from within the Monteiro’s colony on Graciosa in May 2007 (Robb et al 2008) so this potential identification hazard is proven. Monteiro’s Storm-petrel is not called a ‘cryptic species’ for no reason!

A further complication is other taxa of ‘band-rumped storm-petrels’, particularly first-summer from both the summer and winter breeding populations. The dispersal ranges of the various taxa of ‘band-rumps’ are not fully understood, immature or adult and birds from any population in principle could be present in Azorean waters at any time of year. This could lead to confusion in assigning taxa using moult timing. However, despite all the complications, a long-winged non-moulting bird with a deep forked tail in early summer and a similarly structured bird moulting its inner primaries in August/September in the core breeding range can, on balance, safely be considered a Monteiro’s Storm-petrel.

Hitting the jackpot?

We therefore concentrated pelagic efforts on the Bank of Fortune, coordinating three separate trips (with a total of twelve days at sea) in early August 2012, late August 2013 and early September 2013.   Unbelievably, as well as gaining excellent views of Monteiro’s Storm-petrel, each of the three trips recorded a Swinhoe’s Storm-petrel!

Even more outstanding was our discovery of a Zino’s Petrel on the bank in 2011 (which was identified by Bob Flood). This is one of few sight records of this species away from its breeding area, and confirms geolocator studies which show that the species disperses into Azorean waters.

Geolocator studies also incredibly show that Bermuda Petrels regularly disperse into Azorean waters and we hope to connect with one in the future. Bermuda Petrel has already been recorded on the Azores – an individual was famously captured and re-captured in a burrow on several occasions between 2002 and 2006 on Santa Maria.

Further trips were arranged in 2014, 2015 and 2016 confirming the reliability of the Bank of Fortune for Monteiro’s and Swinhoe’s Petrel, with Swinhoe’s recorded on all six trips since 2012. The Bank also held more surprises with Brown Booby in 2013, South Polar Skua in 2014, Fea’s Petrels in  2013 and 2016 and Sooty Terns (a breeding pair on Praia islet) were encountered most years.

The following table shows our pelagic sightings to date, though as more birders and pelagic trips focus on the Bank of Fortune and beyond we’re hopeful of some more significant records. Bob Flood and Ashley Fisher have identified the Azores as ‘The northeast Atlantic Pterodroma hotspot’ based on past records and geolocator studies. So with Zino’s and Fea’s Petrels already recorded, we’re holding our breath in the wait for a Bermuda, Black-capped or Trindade Petrel next…

Zino’s Petrel (Harro Müller). This record received a detailed discussion by Flood and Fisher 2013. Geolocator studies have revealed that birds disperse widely into the North Atlantic from their breeding grounds in Madeira.

Swinhoe’s Storm-petrel (Peter Alfrey). Remarkably, individuals of this species have been seen on each of the last three pelagic expeditions off Graciosa.

Swinhoe’s Storm-petrel (Peter Alfrey). Remarkably, individuals of this species have been seen on each of the last three pelagic expeditions off Graciosa.

Brown Booby off Graciosa, September 2013 (Peter Alfrey). The third record for the Azores.

Brown Booby off Graciosa, September 2013 (Peter Alfrey). The third record for the Azores.

Long-tailed Skua (Peter Alfrey)

Long-tailed Skua (Peter Alfrey)

Fea’s Petrel off Graciosa, September 2013 (Harro Müller)

Fea’s Petrel off Graciosa, September 2013 (Harro Müller)

Great Shearwater off Graciosa, August 2013 (Richard Bonser). Phenomenal views of this South Atlantic breeder can be had alongside the innumerable Cory’s Shearwaters.

Great Shearwater off Graciosa, August 2013 (Richard Bonser). Phenomenal views of this South Atlantic breeder can be had alongside the innumerable Cory’s Shearwaters.

Sooty Tern, Praia Islet off Graciosa, August 2013 (Richard Bonser). One of up to two adults that are regularly recorded in the tern colony on the island.

Sooty Tern, Praia Islet off Graciosa, August 2013 (Richard Bonser). One of up to two adults that are regularly recorded in the tern colony on the island.

South Polar Skua (Richard Bonser). One of the surprise highlights of the 2014 pelagic trip.

South Polar Skua (Richard Bonser). One of the surprise highlights of the 2014 pelagic trip.

Pelagic Trips from Graciosa 2011 to 2016 (Cumulative totals for trips each of 3.5 days at sea)

Species June 2011 August 2012 August 2013 September 2013 August 2014 August 2015 August/

September 2016

Fea’s Petrel       1     2 (fea’s-type)
Zino’s Petrel   1          
Bulwers Petrel 4 18 1 3 11 1 8
Cory’s Shearwater x X x X X X X
Great Shearwater     60+ 100+ 300+ X 130
Sooty Shearwater 5     20+ 7   21
Manx Shearwater 4 5 1 4 6    
Barolo’s Shearwater 3 1     1 1  
Wilson’s Storm Petrel 15 6 7 1 3 3 5
Swinhoe’s Petrel   1 1 1 1 1 1
Monteiro’s Petrel 50+ c20 C30 10+ 50 10+ 120+
‘Grant’s’ Petrel   c10 2+ 2+ 2+   X
Brown Booby       1      
Northern Gannet 1            
Grey Phalarope 1            
Pomarine Skua       1 1 1 1
Arctic Skua       5 3 1 5
Long-tailed Skua     1 3 3 1 2
Great Skua 4            
South Polar Skua         1    
‘Azores Gull’ X X X X X X X
Lesser Black-backed Gull   1 X X X X X
Sabine’s Gull         1    
Roseate Tern X X X 20+ X X X
Common Tern X X X X X X X
Arctic Tern         1    
Sooty Tern 1   1 2 3 1  

*A Solitary Sandpiper was also recorded at sea in August 2012.

*Trindade Petrel was recorded by an independent pelagic birder off Graciosa in 2012.

x- present throughout

Other Wildlife from Graciosa 2011 to 2016 (Cumulative totals for trips of 3.5 days at sea)

Species June 2011 August 2012 August 2013 September 2013 August

2014

August/

September 2016

Sperm Whale   4     1 2
Cuvier’s Beaked Whale 6         4
Northern Bottlenose Whale   1        
Sowerby’s Beaked Whale   1     5 4
Minke Whale   1        
Common Dolphin 200+ 100+ 100+ 100+ 10  
Bottlenose Dolphin 50+ 10+ 20+ 10+ 30+ x
Spotted Dolphin   50+ 20+ 50+ 20+  
Striped Dolphin           25
Risso’s Dolphin 12+ 20+        
Loggerhead Turtle 1 3 2 7    
Sunfish 1          
Blue Shark 3     3 1  
Hammerhead Shark   1        
Oceanic White-tip Shark       1    
Breaching Sowerby Beaked Whales (Richard Bonser). Regularly recorded on the pelagics.

Breaching Sowerby Beaked Whales (Richard Bonser). Regularly recorded on the pelagics.

 Common Dolphins (Gareth Knass)

Common Dolphins (Gareth Knass)

Spotted Dolphins (Vincent Legrand)

Spotted Dolphins (Vincent Legrand)

 Blue Shark with pilot fish (Harro Müller)

Blue Shark with pilot fish (Harro Müller)

Logistics

The best way to see Monteiro’s and Grant’s Storm-petrels, as well as other seabirds on the Azores, is to join an organised pelagic to the area with Peter and Richard in partnership with travel agents Azores Choice and Diving Graciosa. This year’s pelagic trip will run from 27th August to 1st September. So if you are interested in joining this trip (or subsequent trips) please email Peter at littleoakgroup@btinternet.com. This trip can also be combined with a trip to see the Azores Bullfinch, and it’s also likely that the first American waders of the autumn will be arriving in the famous Cabo da Praia quarry.

Acknowledgements

Many thanks to Bob Flood for improvements to the text of this article.

Thanks to all the birders that have participated in the pelagics. Special thanks and indebted to Ian from Azores Choice for sorting out all the logistics and of course to Rolando Oliveira and his crew from Diving Graciosa for taking us out to sea.

2011 Team

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Champions of the Flyway 2017

By Yoav Perlman

Turtle Dove, Nizzana, Israel, August 2012. Photo by Yoav Perlman.

Turtle Dove, Nizzana, Israel, August 2012. Photo by Yoav Perlman.

25 million birds are killed and trapped illegally around the Mediterranean Basin annually – this staggering figure is an estimate by BirdLife International experts. This massacre directly affects bird populations in western Europe and in the UK – declining species like Turtle Dove, Quail and Song Thrush are among those that are most heavily hunted.

I guess many of our followers have heard of Champions of the Flyway (COTF). In brief, it’s an international conservation project, aiming to tackle illegal killing and trapping of birds around the Mediterranean Basin. The project begins with a huge fundraising campaign, and the climax is in a 24-hour bird race at Eilat, Israel on March 28th 2017. The project is coordinated by BirdLife partner in Israel, the Society for the Protection of Nature in Israel, in collaboration with BirdLife International. Each year, BirdLife International chooses a local NGO to receive the funds raised in the project. In the three previous races, over $180,000 were raised for conservation. This may not seem a lot, but for small NGO’s like Sabuko in Georgia or Helenic Ornithological Society in Greece, such funds are vital.

Roula Trigou of BirdLife Greece receives COTF 2016 funds from BirdLife CEO Patricia Zurita

Roula Trigou of BirdLife Greece receives COTF 2016 funds from BirdLife CEO Patricia Zurita

This year, BirdLife partner in Turkey, Doğa Derneği, will receive the funds. They were chosen because sadly Turkey is a hotspot for illegal killing of birds – millions of birds are killed there annually. COTF funds are essential for their incredible work on the ground. Before we started working directly with Doğa, I wasn’t aware of their huge efforts to tackle illegal killing of birds in Turkey. Now I know that they are doing exactly what needs to be done by NGO’s – focused work on educating children and local communities to stop this killing. And with COTF funds, they plan to expand their programs and make them more effective. One unique project they are operating is work with Syrian refugees in Turkey, who know little about conservation and without support and attention will surely hunt birds around where they currently reside. This kind of work that involves humanitarian work, conservation and education is truly groundbreaking. You can learn more about Doğa’s mission here.

Imperial Eagle_locals

Imperial Eagle research

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Some nice migratory birds from Eastern Turkey…

Grey-necked Bunting, Van, Turkey, June 2013.

Grey-necked Bunting, Van, Turkey, June 2013. Photo by Yoav Perlman. Maybe this year a first for Israel will be found on race day?

Paddyfield Warbler, Van, Turkey, June 2013. Photo by Yoav Perlman.

Paddyfield Warbler, Van, Turkey, June 2013. Photo by Yoav Perlman.

This year, COTF bird race will be bigger than ever. It’s an awesome event. Really great. You’ll love it. At the moment 18 international teams are registered – from UK, USA, South Africa, Finland, China, Italy, Netherlands, Spain, Switzerland, Germany and of course Turkey. We take special pride in the Palestinian team – the Palestine Sunbirds. Additionally, there is a parallel Israeli race, that includes currently 20 teams, about half of which are children, youth and women!

 

COTF 2016 participants remembering Martin Garner with a Boom!

COTF 2016 participants remembering Martin Garner with a Boom!

The race itself is a celebration of migration, but also of friendship, stamina and involvement. You can get the feel of the race in this brilliant video of last year’s race:

The three major optic companies, Swarovski, Zeiss and Leica, have supported COTF from the start, and every company supports several teams. Last year, Zeiss Arctic Redpolls won the international race. They are returning this year to defend their title. Will they succeed?

Zeiss Arctic Redpolls - Roni Väisänen, Vilppu Välimäki and Jarkko Santaharju receive their prize from Dale Forbers from Swarovski

Zeiss Arctic Redpolls – Roni Väisänen, Vilppu Välimäki and Jarkko Santaharju receive their prize from Dale Forbes from Swarovski Optik

Each one of the race teams is fundraising now for the conservation cause, through their team pages. Donations are collected by BirdLife International via justgiving.

The migratory birds that pass through Turkey need your help! $5, £5, €5, whatever you can – every cent is important. Please consider supporting one of the teams on the 2017 teams page. Personally, I have special links with several teams, and I recommend donating to them, but feel free to donate to the team of your choice. Here are my teams of choice:

Birdwatch – Birdguides Roadrunners – featuring in this team is my good friend Mark Pearson AKA Fileybirder. Mark was also a very good friend of Martin Garner, and contributes regularly material to Birding Frontiers. His team mates are Dawn Balmer, who is also a good friend of mine, through her work at BTO and OSME. Mike Alibone is an old friend too.

The Spokes Folkes – I first met Gary at 2016 Norfolk Birdfair. We had a good conversation, in which I told him about COTF. Gary got hooked on the idea, and a year later – he has a team! It’s a special team because it’s one of the few green teams in the race – Gary and his young intrepid teammates from Orkney will cycle through the playing field of southern Israel.

My third recommendation is The Golden Pheasents. This team was born in Warham Greens in Norfolk last October, when I went birding with Terry. We didn’t see much that morning, but I am happy that my enthusiasm motivated Terry to form the first Chinese team in COTF. Terry is a close friend and a Birding Frontiers team member too.

I must stress that I have close friends in almost all teams, and all teams represent important organisations and initiatives – Vulture Conservation, Artists for Nature and more. Check the team pages, choose your team or teams – and open your heart.

We have less than three weeks to go to the race. Teams will soon be arriving in Israel, so now it’s time to step up the fundraising. On race day, follow our live updates on Facebook and Twitter. As my mate Jonathan (COTF organiser) says – Bring it!

 

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A nice flock of White-winged Scoters

by Guillermo Rodríguez

Although White-winged Scoter is very common in winter along the east coast of the US and Canada, they are rarely found close enough to shore to see plumage details, or at least rarely in large numbers. In late November 2016, a huge flock of this species built up off Crane Beach, Massachusetts. The 700+ birds were feeding on an unidentified species of mollusk for a period of roughly one week, very close to shore (at least by scoter standards). The Crane Beach flock provided an exceptional opportunity to study a large number of individuals, which I couldn’t let pass. Despite the freezing ocean breeze on a very windy day, I managed to take a good number of pictures that show the variability of some key characters well.

Below I present a small sample of my pictures from that day, with the goal of revisiting and testing some of the identification and ageing criteria (presented in eg Garner et al. (2004), Reeber (2016)).

WARNING! This post contains many pictures!

All photos were taken on November 23rd, 2016, in Massachusetts. Note that due to the warm light of the sunrise most birds look very brown-tinged, but they usually look much darker in the overcast light conditions that are typical of NW Europe.

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The mollusk they were feeding on – Eastern Slippery Shell?

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White-winged Scoter: a juvenile male (right at the center) with three adult females and three adult males.

Adult males (including second-years)

Here are some pictures of adult males showing the variability of the bill pattern, the white tick mark at the eye, and the extension of brown on the flanks. As is well known, the characteristic head shape and the bill pattern allow a straightforward separation from both Stejneger’s and Velvet Scoters.

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White-winged Scoter, adult male.

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White-winged Scoter, adult male. Note the particular shape of the flank feathers.

This male (below) presents a “hint of horn”, not very different from that shown by some Stejneger’s (see, for comparison, the Stejneger’s seen in December in Alicante, Spain), and a quite equilateral nostril. The “two-stepped” head profile, lacking the oval, eider-like shape of Stejneger’s, is still very obvious.

comparacion_stejnegeri_lowres

White-winged Scoter (left) and the recent Stejneger’s Scoter (right) from Alicante, Spain. The Stejneger’s picture © Jana Marco, one of the finders of this mega!

Some second winter individuals completely lack the white mark behind the eye, whereas in others it’s present but is still shorter than in older birds. Head and bill shape, including the markedly two-stepped profile, is usually not fully developed at this age and some still show a relatively flat head profile. Bill tip is uniformly pink, with thicker black margins than in adults. Lack of the tricolored bill pattern of adults is also typical of a young age. Some of these young adult males seem to lack the brownish feathers on the flanks, and look more uniformly black than adults.

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White-winged Scoter, second year male, lacking white tick mark.

second winter vuelo IMG_0655

White-winged Scoter, second year male, with limited eye tick mark.

young male comparison IMG_1181

White-winged Scoter, “young” adult male (presumed 2w), showing typical immature features such as greyish iris and pink bill, lacking any yellowish or orangeish tones.

adult male and yound IMG_1272

White-winged Scoter, adult male (left) and a male showing some immature traits (right), eg short eye tick mark, pink bill and not fully developed bill knob.

[Ageing female-type birds]
Ageing of female-plumaged birds is often simple, as many adult females are completely dark and even jet black. Differences in the head shape, the shape of the wing coverts (which are uniformly fresh and rounded in juveniles, and more squared in adults) and the paler belly in juveniles are also supportive. However, the most important feature for me is probably the pattern of the GCs and, in particular, the presence of white tips. The pattern is usually difficult/impossible to see when the birds are on the water, so it usually requires pictures in flight:
adult females: completely dark inner GCs, but the white tip sharply increases in size in the meadial GCs and can occupy almost the entire feather
first-year males: usually a small spot at the feather tip, of uniform size in all the Gcs or at most a gradual and slight increase, but always occupying <50% of the feather
first-year females: very small or completely absent white spot in all GCs

adult female vuelo IMG_0648

White-winged Scoter, adult female: note largely white medial GCs, bright reddish feet, squared wing coverts, very broad primaries.

female oscura vuelo IMG_8805

White-winged Scoter, adult female.

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White-winged Scoter, first winter male: limited amount of white in the GCs

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White-winged Scoter, first winter male.

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White-winged Scoter, first winter female.

I guess ageing criteria are the same for Velvet, but I never had the chance to look into the subject in detail in Europe (Velvet is regular but scarce in Spain). I usually find it problematic to understand the pattern and variability of s1, which is sometimes described as the key feature to age these scoters, so I won’t make further comments on this feature.

Adult females

Adult females vary from very dark birds (looking like a “dirty” version of adult males) to those having the more classic brown plumage with two pale areas on the face. I think that the first type is actually much more common than the latter; the number of these overall black birds within the population appears to be only slightly lower than the number of adult males eg from a sample of 205 birds, 14.6% were adult males and 12.2% were these black presumed females. I wonder if there is an age-related variability, and the black birds are actually the older females.

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White-winged Scoter, adult female.

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White-winged Scoter, adult female: note the squarish shape of the wing coverts.

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White-winged Scoter, adult female.

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White-winged Scoter, female: dark below, slight bill bump, apparent bright feet, not very uniform back feathers… not sure about the age, could this bird be an adult?

The black-plumaged individuals are sometimes identified as first-year males with an extensive first pre-formative moult, but I think this explanation can be safely ruled out based on the GCs pattern (see the shots in flight above), the bright color of the feet, the dark irises, and the squared wing coverts shown by most of these birds. Only when the formative moult is much more advanced, around late January/February, first-winter males look similar, although with a much dirtier plumage, often looking “patchy” and not as uniformly jet black.

adult females with first year juv deglandi first winter male IMG_0199

White-winged Scoter, two adult females with a first-year male (right).

The head shape of these birds actually recalls that of adult males, due to a squarish head with a flat crown, a straight (non-concave) forehead profile and the hint of a bump at the bill base, leading to a two-stepped head profile, although it is much smoother than in males. Although the differences are sometimes subtle, I think these features are distinctive enough to allow separation from Velvet in most cases. Take a look at this compilation to get a sense of the variability in head and bill shape in adult females:

adult_female_lowq

White-winged Scoter, adult females: variability in head and bill shape.

Note that some adult females present some diffuse pink “brush-strokes” at the bill tip, but the iris seems to be pretty dark in all the individuals (cf first winter males, see below).

First-year males

By late November, juveniles still look very fresh, and the pale velvet at the base of the bill often looks nicely neat. Around 40-50% show what seem to be signs of moult around the face, and a few males have already developed a pale greyish iris and pink in the bill. But even birds that still have a completely juvenile appearance can be readily sexed by the elongated bill and very flat head profile, in contrast to females, which show a shorter bill and often a slightly angular (concave) head profile.

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White-winged Scoters, first-year male (left) and first winter female (right). In my opinion, many juveniles can be reliably sexed in the field on grounds of the head and bill shape. Note, on the back, another first year female (left) and first year male (right).

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White winged Scoter, first year birds. Sexing is definitely not always possible – this bird (center) looks intermediate, or perhaps on the female side?

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White-winged Scoter, first-year male: a nice bird still in completely juvenile plumage.

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White-winged Scoter, first-year male: gradual lightening of the iris, traces of moult around the face.

undetermined IMG_0293

White-winged Scoter, first-year male. This looks like a VERY advanced first year male.

Regarding the separation from Velvet, in addition to the head shape, the shape of the feathering at the base of the bill is quite distinctive given sufficiently close views; it extends further onto the bill than in Velvet and forms a 90-degree angle in the lower corner, always below the position of the nostril. A few more examples of (presumed) first-year males:

first_winter_male

White-winged Scoter, first-year males: variation in head and bill shape.

firsst winter male bill IMG_1254

White-winged Scoter, first-year male. Interesting individual with a narrow bill, and relatively rounded shape of the feathering at the lower corner of the bill base.

First-year females

Undoubtedly the most problematic group, many first-year females look very similar overall to Velvet Scoter. With short bills, and often concave and rounded head profiles, it may be extremely difficult to pick one out among a flock of Velvets. However, the shape of the feathering at the base of the bill, even if it is not as distinctive as it is in males, is still quite a good character when properly seen. Most birds (>60-70% ?) clearly show, below the nostril, a right angle:

first year pico ejemplo IMG_1247

White-winged Scoter, first-year female.

first year female perfect IMG_1267

White-winged Scoter, first-year female.

hembras cabezas IMG_0380

White-winged Scoter, first-year females. In a few juveniles, the pale spots merge, giving a striking appearance.

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White-winged Scoter, first-year female – convex and rounded head profile, similar to Velvet.

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White-winged Scoter, first-year female: variation in head and bill shape.

In a few birds the angle is not as sharply defined, looking rounder and closer to the nostril, and the pattern is probably consistent with Velvet. But this seems to be the exception and not the norm!

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White-winged Scoter, first-year female, showing a rounded corner of the feathering at the bill base.

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White-winged Scoter, presumed first-year female.

Variation in adult Cabot’s Tern and Sandwich Tern

By Yoav Perlman

With special assistance from Mike Langman and Guillermo Rodriguez

These two tern species from both sides of the Atlantic look very similar, but in fact are not even the closest relatives – based on genetics, Cabot’s Tern was found to be a sister species of Elegant Tern. Sandwich Tern Thalasseus sandvicensis is monotypic, and Cabot’s Tern includes Thalasseus a. acuflavida and another taxon – Cayene Tern T. a. eurygnatha. This post deals only with nominate acuflavida.

In his Challenge Series Autumn book, Martin Garner dedicated a chapter to them. And of course there’s Garner et al. 2007 DB article. Though not a frequent visitor to Europe as other American gulls and terns, the potential to find a Cabot’s Tern in Europe remains, in light of records of both taxa on both sides of the Atlantic. Additionally, one individual in October 2016 on Tereceira, Azores in October 2016 was first claimed as Cabot’s Tern and caused a bit of a headache. Therefore, I think it is worth revisiting the main ID criteria to separate the two species. I must stress that I am no expert on Cabot’s Tern ID, so I hugely appreciate the valuable help I received from Mike Langman, Guillermo Rodriguez and Julian Hough who certainly are experts. In this post I will try to demonstrate some variation in both species regarding main ID criteria, but I think that still most individuals can be safely identified, within the known limits of variation. That’s why it’s important to document and acknowledge this variation in both species.

Bill structure

The thumb rule is that Cabot’s Tern has a thicker, heavier-based and straighter bill, with an obvious gonydeal angle. Not quite Great Black-backed Gull gonys, but it is still there. Most literature mentions that Sandwich Tern has a proportionately longer bill, without any gonys (really?), and a distinct drooping tip.

I don’t know much about bill development in terns, but I know that in gulls very often adults have heavier bills than young birds, with more pronounced gonydeal angle. The same goes for sexual differences in bill structure – male gulls have larger and heavier bills than females. So possibly some variation in tern bills is age and sex related?

This is a nice, heavy-billed Cabot’s Tern (in April, I know…) showing a pronounced gonys:

Cabot's Tern, High Island, Texas, USA, April 2016. Photo by Guillermo Rodriguez

Cabot’s Tern, High Island, Texas, USA, April 2016. Photo by Guillermo Rodriguez

This Cabot’s Tern has a slightly thinner bill with almost no gonys, but it is still very straight, lacking the drooping tip of a sandwich.

Cabot's Tern, High Island, Texas, USA, April 2016. Photo by Guillermo Rodriguez

Cabot’s Tern, High Island, Texas, USA, April 2016. Photo by Guillermo Rodriguez

This is a typical Sandwich Tern, with a long, slender bill, distinctly downcurved, and lacking any gonys:

Sandwich Tern, Arrecife , Lanzarote, Canary islands, September 2011. Photo by David Perez

Sandwich Tern, Arrecife, Lanzarote, Canary Islands, September 2011. Photo by David Perez

Though some Sandwich Terns show a rather pronounced gonys, the bill always looks slender and downcurved:

Sandwich Tern, Arrecife, Lanzarote, Canary islands, October 2011. Photo by David Perez

Sandwich Tern, Arrecife, Lanzarote, Canary Islands, October 2011. Photo by David Perez

Note also that in literature it is mentioned that on average, adult Cabot’s Terns shows a more extensive yellow tip to the bill than Sandwich Terns. There is lots of variation in this, and I suspect that like in other terns this variation in bill tip pattern may be related to breeding condition and sex.

Pattern an overall ‘darkness’ of primaries

Cabot’s Tern has generally darker primaries than Sandwich Tern. There is a difference between the two species in both the base colour of the primaries, and the width of the pale fringes to each primary, especially on the inner web. Sandwich tern also shows a pale ‘hook’ on the outer webs of old and new primaries, while Cabot’s tern apparently never has pale markings on the outer webs. It should be noted that in both species, old and worn primaries before moult are darker and have narrower pale fringes, so a worn Sandwich Tern just before moult can look as dark as a freshly-moulted Cabot’s Tern. Therefore, it is important to understand whether the primaries used for identification are fresh or worn.

This is a typically dark-winged Cabot’s Tern, in late September:

Cabot's Tern, Tulum, Yucatan, Mexico, 25 September 2016. Photo by Mike Langman.

Cabot’s Tern, Tulum, Yucatan, Mexico, 25 September 2016. Photo by Mike Langman.

Check this individual, also in late September: it has an overall paler wingtip, with rather broad pale outer webs. Also, it is not easy to understand the exact pattern of the worn outer primaries. Seem to have no pale on the outer webs but I’m not sure what exactly is going on there:

Cabot's Tern, Tulum, Yucatan, Mexico, 25 September 2016. Photo by Mike Langman.

Cabot’s Tern, Tulum, Yucatan, Mexico, 25 September 2016. Photo by Mike Langman.

Sandwich Tern typically gives a pale impression to wingtip, with prominent pale inner and outer webs to outer primaries, that it had almost completed moulting in October:

Sandwich Tern, Arrecife, Lanzarote, Canary Islands, October 2011. Photo by David Perez

Sandwich Tern, Arrecife, Lanzarote, Canary Islands, October 2011. Photo by David Perez

This September Sandwich Tern has a really dark wingtip, with very narrow pale fringes to visible outer primaries:

Sandwich Tern, Salinas de la Tapa, Cadiz, Spain, 9 September 2011. Photo by David Perez.

Sandwich Tern, Salinas de la Tapa, Cadiz, Spain, 9 September 2011. Photo by David Perez

Moult (or molt?) timing

There is some conflicting information about this. Adult Sandwich and Cabot’s Terns perform an arrested moult, in which it replaced 5-6 inner primaries before migration, and then the rest after migration. In ‘Challenge Series Autumn’ Martin Garner wrote that Sandwich Tern moults earlier than Cabot’s and mentions that Cabot’s moults the outer primaries late, in December – January, with some individuals showing unmoulted primaries in March. Pyle mentions in his book that Cabot’s moult P8-P10 Between October and March. Malling Olsen and Larsson even write in their tern guide that P10 can be moulted between March and June. Quite a broad temporal window. And to make it even more complicated, according to the brand new BTO guide Identification of European Non-Passerines, some Sandwich Terns complete their moult by late October, while others complete this moult only in winter. So a complete or near-complete moult in mid-autumn (October) indicates Sandwich Tern, but it doesn’t seem to work the other way – late moult in late autumn (November – December) does not necessarily exclude Sandwich Tern. Using early moult to identify a vagrant Sandwich in North America is fine, but late moult is not necessarily a sign for a vagrant Cabot’s in Europe.

Crown pattern

Basically, Cabot’s Tern has darker and more solid rear crown, with longer feathers and very few if any white tips. Crown is rather clean white. Cabot’s also tend to show more black around and in front of the eye. Not sure about this one… Sandwich Tern has a paler rear crown, with more white tips – often referred as ‘peppered’ rear crown. There are more dark feathers on the crown itself. However… variation here too. Quite a peppered rear crown on this September Cabot’s. Top crown is clean though.

Cabot's Tern, Tulum, Yucatan, Mexico, 25 September 2016. Photo by Mike Langman.

Cabot’s Tern, Tulum, Yucatan, Mexico, 25 September 2016. Photo by Mike Langman

This is a more normal-looking Cabot’s tern, with a rather solid black rear crown, though there are quite many white feathers mixed. Very clean white crown. But oh no, look at the pale ‘hook’ around the primaries…

Cabot's Tern, Florida, USA, 21 January 2007. Photo by Julian Hough.

Cabot’s Tern, Florida, USA, 21 January 2007. Photo by Julian Hough.

A beautiful demonstration of the dirty crown of Sandwich Tern:

Sandwich Tern, Ijmuiden, Netherlands, 23 September 2012. Photo by Marten Miske

Sandwich Tern, Ijmuiden, Netherlands, 23 September 2012. Photo by Marten Miske

Check the rather solid dark rear crown of this October Sandwich Tern:

Sandwich Tern, Norfolk, UK, October 2016. Photo by Mike Dawson

Sandwich Tern, Norfolk, UK, October 2016. Photo by Mike Dawson

Terceira, Azores, October 2016 individual

This individual was on the Nearctic magnet archipelago last October. Some friends are writing about this individual so I will refrain from expressing my view on it. Here are some images – judge for yourself:

... Tern, Terceira, Azores, October 2016. Photo by Mika Bruun.

… Tern, Terceira, Azores, October 2016. Photo by Mika Bruun.

... Tern, Terceira, Azores, October 2016. Photo by Mika Bruun.

… Tern, Terceira, Azores, October 2016. Photo by Mika Bruun.

... Tern, Terceira, Azores, October 2016. Photo by Daniel Mauras.

… Tern, Terceira, Azores, October 2016. Photo by Daniel Mauras.

In the next episode – hatch-year birds…

Many thanks to all the talented photographers, to Killian Mullarney and to Nick Watmough who contributed to this post!

Sykes’s Nightjar – new to Oman

By Yoav Perlman

Happy New Year to all our followers. Hope you had a great holiday.

I received this nice story from two Spanish birders who visited Oman in December 2016 – Albert Burgas and Àlex Ollé. Oman is a true frontier for WP birders – such an amazing country with strong Afrotropical and Asian influences. So many birds waiting to be found there. Must visit there soon. And I love nightjars… Anyway, here is their story:

During a short trip to Oman in December 2016 we visited Muntasar Oasis in central Oman (19°27’11.8″N 54°37’13.9″E) on the 12th. We had a rewarding dusk encounter with a lovely Egyptian Nightjar Caprimulgus aegyptius, hunting and sitting in front of us at Qatbit Oasis. We watched two Mountain Gazelles Gazella gazella cora and one Jerboa sp. when a relatively small and pallid nightjar flew in. It had large and well marked white wing spots and prominent white tail corners, excluding Egyptian Nightjar. At that moment we speculated that it could be a European Nightjar Caprimulgus europaeus. However, European Nightjar is a familiar species for us and that nightjar looked different. The bird was flying and sitting regularly, so we decided to approach the bird with a spotlight. We approached it down to barely two meters and got some photos. At that moment it was obvious that we were not watching a European Nightjar, based on its smaller size, different jizz and pallid colouration. With the available information we had at that moment we supposed that it was a Nubian Nightjar Caprimulgus nubicus as the most probable species. That would be the 8th record for Oman. 

A few days later back home we revisited the issue of the intriguing nightjar. Checking on Internet for other nightjar species from neighbouring countries around Oman we found Sykes’s Nightjar Caprimulgus mahrattensis. That fitted 100% with the bird we photographed, but a far more unexpected species than Nubian Nightjar. We sent the pictures and description to renowned ornithologists from the Middle East to confirm our identification. 

Sykes's Nightjar, Muntasar Oasis, Oman, December 2016. Photo by Albert Burgas.

Sykes’s Nightjar, Muntasar Oasis, Oman, December 2016. Photo by Albert Burgas.

Sykes's Nightjar, Muntasar Oasis, Oman, December 2016. Photo by Albert Burgas.

Sykes’s Nightjar, Muntasar Oasis, Oman, December 2016. Photo by Albert Burgas.

Sykes’s Nightjar breeds in south-east Iran, south Afghanistan, Pakistan and north-west India. It migrates in winter to west, north and central India. There are only four previous records of Sykes’s Nightjar in the Arabian Peninsula, all of them from the UAE and always found between the end of December and February (Oscar Campbell pers. com.). Pending acceptance by Oman Rarities Committee, this is the 1st record of Sykes’s Nightjar for the Sultanate of Oman and the 5th for Arabia.

Some notes on ID by YP:

I am no expert on Sykes’s Nightjar, but this looks good. It is not a Nubian Nightjar – main difference is the throat pattern: Nubian has a well-patterned throat, with a pale moustachial stripe and a whitish throat. Also, Middle Eastern Nubian Nightjars tend to be more heavily marked overall, but this can show very different in photos, depending on the misleading ‘flattening’ effect of spotlighting on photos, and image processing.

'Tamarisk' Nubian Nightjar, Neot Hakikar, Israel, October 2011. Photo by Yoav Perlman.

‘Tamarisk’ Nubian Nightjar, Neot Hakikar, Israel, October 2011. Photo by Yoav Perlman.

Egyptian Nightjar is larger and longer-winged, and lacks the complete rufous neck collar both species above show.

Egyptian Nightjar, Dead Sea, Israel, December 2016. Photo by Yoav Perlman.

Egyptian Nightjar, Dead Sea, Israel, December 2016. Photo by Yoav Perlman.

Egyptian Nightjar, Neot Hakikar, Israel, March 2012. Photo by Yoav Perlman.

Egyptian Nightjar, Neot Hakikar, Israel, March 2012. Photo by Yoav Perlman.

For comparison, here are two Sykes’s Nightjars from Gujarat, India – courtesy of Mike Watson. There seems to be some variation in the extent of black markings on the scapulars between these individuals and the Oman bird.

Sykes's Nightjar, Gujarat, India, February 2015. Photo by Mike Watson.

Sykes’s Nightjar, Gujarat, India, February 2015. Photo by Mike Watson.

Sykes's Nightjar, Gujarat, India, February 2015. Photo by Mike Watson.

Sykes’s Nightjar, Gujarat, India, February 2015. Photo by Mike Watson.

Many thanks to Àlex and Albert for contacting me and sharing their exciting discovery.

Christmas fudge goose

By Yoav Perlman

Geese are fun, aren’t they? The perfect head-scratching activity for dark and cold winter days. In Norfolk, views are typically rubbish, which makes it even more fun. Hybrid geese have been discussed on Birding Frontiers before.

When geese turn up in funny places, things get really interesting. This intriguing goose was found at the spectacular KKL Agamon Hula in Israel on Christmas day by Hamudi Musa Heib, and was later photographed by Dror Galili. Dror kindly allowed me to use his images here. Shai Agmon sent me some more images and shared his field impressions with me. It was an overcast day (even in Israel…) so Dror’s images are rather dark and blue.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

First impression is Lesser White-fronted Goose (LWFG), isn’t it? The bold eyering shouts loud. But then a closer look does show some pointers to other or mixed identities. In images it looks quite a brute, compared to Wigeon. However, people who saw it in the field said that the field impression wasn’t that massive. The neck is thick but rather long. The bill is long and powerful, different from the cute mini-beak of LWFG, to my eyes closer to Eurasian White-fronted Goose (EWFG).

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

First, ageing this bird is important – this appears to be a 1cy (1st-winter; it will turn 2cy in five days). Check moult contrast in scapulars and flanks. It is probably moulting out of juvenile plumage.

Goose sp. with Eurasian Wigeon, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeon, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Some context: 

This is a special goose year in Israel. All geese are rare in Israel. The only regularly occurring species in Israel is Eurasian White-fronted, with single birds seen almost every winter. Agamon Hula is a hotspot for them. This winter Israel is experiencing a goose influx, with several flocks of White-fronts around the country, several flocks of the rare Greylag, and even records of mega rarities – Taiga Bean Goose (5th record) and Lesser White-fronted (7th record). Check this article in Hebrew (sorry), Google Translate will make you chuckle I’m sure. So it is likely that this bird is of wild origin.

In Israel this bird was first broadcast as Lesser White-fronted Goose. Then talk started about hybrid options.  With Eurasian white-fronted Goose? Red-breasted Goose? Egyptian Goose? Ruddy Shelduck? Perhaps wildfowl collections can create unlikely love stories? I don’t know if that’s even possible. So many question marks in one post… So to make some sense I contacted Dave Appleton from the excellent Bird Hybrids. Dave sent me this most detailed reply:

“Firstly I think the reddish colour on the flank feathers is a red herring… I think it is dirt and not a real plumage feature.  I don’t think any hybrid combination would give rise to such a plumage mark and also I don’t think the pattern of it really fits any normal feather patterns – it seems to cross feathers in a weird way, not like a normal plumage feature.  For example in IMG1897 (the top image in this post – YP) the rearmost blotch of reddish brown along the rear flanks seems to cover the outer half of the tip of one feather and the outer ¾ of the base of the feather behind it – like a random spot of dirt rather than a normal plumage pattern.

The other issues would all be explained, I think, if there was (Greater/Eurasian) White-fronted Goose influence – a first-winter would show a dark nail to the bill and have a longer bill than Lesser White-front, it would be large and heavy and I think the head shape and colour are ok too.  So then my question becomes, is it a hybrid between White-fronted Goose and Lesser White-fronted Goose, or could it be just a pure White-fronted Goose?  The features you mention as making it superficially like Lesser White-fronted Goose are the eye-ring and the long primaries.  To me the feathers at the wing-tip look dishevelled – the tertials aren’t lying flat and the primaries seem to be pointing at a slightly odd angle.  I am not sure if it is damaged or has loose feathers, but whatever the cause I am not sure it is safe to judge the relative length of the primaries in this state. 

That leaves only the yellow eye-ring (or more correctly, orbital ring) to potentially indicate Lesser White-fronted Goose origin.  Of course White-fronted Goose can have a slightly yellowish orbital ring, it’s just that its usually so dull and inconspicuous that you don’t notice it.  It does vary though – e.g. the Reeber Wildfowl book says (under the description of adult Greater White-fronted Goose), “Brown iris with a usually inconspicuous orbital ring, which is sometimes yellow (most frequently in breeding males).”  I can’t find them now but I’m sure I’ve seen photos of apparently pure White-fronted Geese with yellow orbital rings that would make a Lesser White-front proud.  Of course your bird appears to be a first-winter, so that may be more unusual in a bird of that age, but I am not sure it is enough on its own to exclude a pure White-fronted Goose.  On the other hand they say that most captive Lesser White-fronts are not pure, having some White-front ancestry (which in my experience rings true – they often seem to have less white on the forehead than wild birds) and I guess the opposite might be true of captive White-fronts.  So if captive origin is likely then perhaps mixed ancestry might be the best way of explaining the yellow eye-ring, but if wild origin is more likely (and if recent events in England are anything to go by it must be a good winter to see White-fronts a bit outside their usual range) then I would tentatively suggest a pure first-winter White-fronted Goose would be the most likely identification.”

Many thanks to Dave for this interesting and eye-opening analysis.

I have some points to discuss though – open to debate:

  1. I think the red colouration on the flanks is genuine feather pattern, rather than red dirt. It seems to be symmetrical on both sides (check two top images).
  2. I agree that wingtip structure is not fully clear in relation to tertials, but the primaries do certainly project beyond tail. It is hard to judge exactly how much, but this is more than I would expect from a EWFG.
  3. I am not sure that the dark bill nail is not a result of the goose digging in the dark peat soil of the Hula Valley.

Would be interesting to hear more opinions on this bird!

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeon, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeon, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp., Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

Goose sp. with Eurasian Wigeons, Agamon Hula, Israel, 25/12/16. Photo by Dror Galili.

I apologize for a certain back-log I have here on BF. I promise to address the grey chat (stejnegeri?) issue soon. I also have some interesting terns in the oven, and should also write about a certain house martin that I hope to see on Thursday when I arrive in Israel for a short visit…

So stay tuned for some more exciting stuff here on Birding Frontiers in 2017. I wish all of our followers and supporters a lovely and exciting 2017!