Tag Archives: identification

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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.

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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.

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

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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.

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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

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

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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.

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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:

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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.

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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:

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

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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:

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White-winged Scoter, first-year female.

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White-winged Scoter, first-year female.

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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.

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Holboell’s Red-necked Grebe

by Guillermo Rodríguez

The American/East Asian subspecies of Red-necked Grebe, P g holboelliii, has been observed in the WP with accepted records in the UK (a bird shot in Wester Ross in September 1925 and subsequently identified based on measurements), Spain (two winter records from Galicia in 1984 and 1987, which were identified in the field, although these records will likely be reviewed again in the near future by the Spanish Records Committee), Iceland (at least five), and single accepted records in Sweden and Norway, in addition to several other reports. Since they are quite common as wintering birds along the American Atlantic coast (where, for instance, Pacific Diver is scarce/rare), they should be expected to reach Europe regularly. But do they?

holboellii is known to be larger and darker, and to have more yellow in the bill than the nominate grisegena. According to Pyle (2008), the differences in size are likely to be significant enough to clinch the ID. For example, the wing length is 180-212mm in holboellii versus 153-188mm in grisegena, showing that there is limited size overlap. However, these differences would obviously require in-hand measurements for identification. It’s my understanding that separation of holboellii from grisegena is currently considered to be impossible under field conditions, and the validity of the pattern of yellow in the bill has also been questioned (because a few grisegena show yellow bills similar to holboellii). However, the longest-billed holboellii show impressive harpoon-like bills which, in my opinion, are clearly outside the range of variation of grisegena.

Another identification feature that’s not usually mentioned in the literature is the general body structure; holboellii is considerably more powerful, with a longer neck, a longer and stronger bill and a flatter forehead. The head often looks square rather than rounded (although it’s also important to consider the age-related variation of the head shape, since first-winter birds tend to show rounder heads in general). As a useful comparison, holboellii somewhat resembles Great Crested Grebe. The main problem is that structure is subject to interpretation, and any identification solely based on the jizz is usually disputable. Variability in body shape is also quite extensive, and in particular many American holboellii may look as small and delicate as European grisegena. On the other hand, the largest-billed grisegena are at the same time the biggest individuals, with a more powerful structure than average birds, altogether favouring the holboellii impression.

Still, I do think that the largest and most striking holboellii could be definitively identified in the field if one turns up in Europe. For instance, check out two examples of such extremely large birds here and here.

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Red-necked Grebe ssp. holboellii, first-winter, February 2014. New Jersey. Picture by Sam Galick.

Many first-winter holboellii show a striking pale iris, which forms a contrasting ring around the dark eye that is very obvious with close views. I don’t know the variation in grisegena well (any feedback is welcome!), but my impression is that it isn’t always so obvious; perhaps the iris is on average paler in holboellii?.

The structural differences are easily noticeable even in distant birds at sea:

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Red-necked Grebe ssp. holboellii, December 2015. Massachusetts. Picture by Guillermo Rodríguez.

Sadly not all individuals are so distinctive; for instance the bird below – although it still looks large and long-billed – is probably still consistent with grisegena.

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Red-necked Grebe ssp. holboellii, adult, December 2015. Massachusetts. Picture by Jeremy Coleman.

And actually many holboelli look much smaller, more delicate and round-headed:

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Red-necked Grebe ssp holboellii, December 2005. Massachusetts. Picture by Tom Murray.

As a rough estimate, I would say that on the east coast of the United States the proportion of birds that are 1) markedly large and powerful, 2) intermediate 3) small, grisegena-like is somewhere between 20-40-40(%) and 10-30-60(%). My impression from a winter trip to Korea is that Asian holboellii on average are even more obvious, but at the time I didn’t pay enough attention (see some examples from Japan here).

Some birds, particularly adults, are remarkably dark, especially on the flanks; in addition, the facial dark mask sometimes extends towards the cheek.

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Red-necked Grebe ssp. holboellii, adult, November 2012, Massachusetts. Picture by Christopher N. Ciccone.

A couple of birds from Spain

One obvious problem with using structural features for identification is that they are strongly affected by the posture and activity of the birds. Take a look at this (presumed) grisegena from northern Spain photographed on two different days. I have the impression that birds at sea tend to look more like holboellii than birds on calmer waters, such as estuaries, where they tend to look more like grisegena. Presumably this is because the latter are more relaxed, but it’s difficult to say.

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Red-necked Grebe ssp grisegena, February 2016. Cantabria, N Spain. Picture by Lander Zurikarai.

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Red-necked Grebe ssp grisegena, February 2016. Cantabria, N Spain. Picture by Jesus Menéndez.

The amount of yellow on the bill of this bird is similar to that shown on all the holboellii in previous photos, extending over the entire lower mandible and reaching the upper mandible up to the nostrils.

In March 2015, an interesting Red-necked Grebe was found in Galicia, northwest Spain. The bird was remarkably dark on flanks and cheek and presented a substantially long neck, strong structure, and powerful bill, which accentuated its long-headed impression. This bird was probably within the size range of grisegena (at least it wasn’t one of the obvious and “identifiable” holboellii) and the reduced yellow in the bill was certainly against it being holboellii, but it still gave a Nearctic impression.

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Red-necked Grebe, first winter, March 2015. Galicia, N Spain. Picture by Jose Luis Lorenzo Garcia “Colon”.

Taxonomical notes : Lesser Kestrel is really monotypic?

With these “taxonomical notes” I want to launch a series of notes and thoughts about some problem related to the taxonomy of Western Palearctic birds, addressing some conundrums which have not yet been studied in detail or did not get enough attention. Many of these notes are simply reported in order to stimulate further in depth studies by taxonomist and researchers, with some being instead only a brief view of my researches in due course and in progress. Indeed, for what concern this “first case” here reported, my study started back in Autumn 2003 and the whole problem will be presented on a specific paper in preparation.

Taxonomical notes : Lesser Kestrel is really monotypic?

By Andrea Corso

During autumn 2003, I was at Chockpak Ringing Station, Kazakhstan, alongside with three  Dutch birders and friend of mine (Arend Wassink, Justin J Jansen and Wim Nap), studying raptors and the other birds there, with the guiding of Professor Andrei Gavrilov. We visited as well many other sites of Eastern Kazakhstan. The trip was very interesting and fruitful for many aspects and the country was confirmed to be one of my favorite destination. Among the several remarkable observations, I was greatly intrigued by the pattern of the upperwing in most of the adult male Lesser Kestrel ringed and observed in the field. During the firsts observation days in Kazakhstan I was telling my fellow observers some tips about field characters of Lesser Kestrel. While talking about the upperwing grey panel in adult male I emphasized how this character is very often not visible under field condition and usually only at very close view, good light or in perched birds. Looking at the males flying around then, I was readily contradicted, as in all the males around, the grey on the upperwing was not only well visible, even at distance, but also very conspicuous and dark looking. This fact intrigued me very much so I started to check and study in details every male observed in the following days and eventually also all the birds caught to be ringed. It resulted therefore as almost 100% of the males observed shown more grey then I was used to see in European birds; this was confirmed by the many males caught during our stay at the ringing station. For what concern European birds, Corso (2000, 2001) report that to a certain degree, the upperwing grey panel could show a range of variability, among several other characters. However, not any of the European bird personally observed (some 20.000 adult males in total) ever shown an upperwing pattern that may look identical to the birds I observed in Kazakhstan. Rarely, birds within European population (chiefly from the eastern part of the range) may show a more extensive grey wing-panel, with all the GC (greater coverts) sooty-grey and in rare occasion some median coverts (MC) and tertials too (Corso, 2000, Corso, 2001; pers.obs.).  However, I never observed any European bird with almost the whole upperwing coverts dark led-grey all the way to scapulars and tertials as in some Kazakhstan birds.  None of the main references on European raptors either illustrate or describe birds like these (Cramp & Simmons, 1980; Snow & Perrins, 1998; Forsman, 1999; Clark, 1999; Ferguson-Lees & Christie, 2001). None of them even mention that the grey area (panel) appear to be greater in Eastern populations then in the Western populations. Only in Ferguson-Lees & Christie (2001) it is depicted a bird with more grey then usual but not as much as noticed in this study. In Forsman (1999), the only picture showing a male with much grey on upperwing has been taken in fact in Kazakhstan. I was therefore very excited as I thought to have found a yet un-described subspecies of the believed monotypic Lesser Kestrel. However, once back home, I started to search references on the taxonomy of this falcon and found that back in ‘800 a “variety” or race has been already described by Swinhoe.

Introduction

Nowadays, Lesser Kestrel Falco naumanni (Fleischer, 1818) is considered monotypic, with no subspecies recognized (Cramp & Simmons, 1980; Snow & Perrins, 1998; Forsman, 1999; Clark, 1999; Ferguson-Lees & Christie, 2001; Corso, 2000, 2001). However, Swinhoe described in 1870 a new race or “variety” (according to his given name) of Lesser Kestrel from Pekin, China which he named Falco cenchris var. pekinensis (Swinhoe, 1870). He described the holotype bird, collected on 18th October 1868, as following : “Large numbers of Kestrels were flying and hovering about. Their movement struck me as peculiar; and on shooting a male we found the species to be a race of Falco cenchris, Naumann. We procured on this occasion an adult male, and in the Western Hills a young male. They agree in size and form with Falco cencrhis of Europe; but the adult male has all the wing-coverts grey right up to the scapulars, most of them narrowly edged with rufous. The adult has the inner or short primaries broadly bordered at their tips with whitish, rufous in the immature, and wanting in the European bird. Both adult and immature have the white on the under quills 3 ¼ inches short of their tips; in the European bird it advances one inch nearer the tips. I will note this Eastern race as var. pekinensis. It will probably be the bird that winters in India.” (Swinhoe, 1870). Later on, Swinhoe (1871) on his “Revised Catalogue of the Birds of China” so reports “Breeds on the western hills of Pekin, and assembles in large numbers in September. Mr. Hodgson’s drawing of the Nepal bird (in the British Museum) shows that it is this race of Tichornis cenchris that resorts to India. The adult male has all the wing-coverts grey right up to the scapulars ; the inner or short primaries are broadly bordered at their tips with whitish, rufous in the immature ; the white on the under quills is 3^inches short of their tips. Subsequently, Jerdon (1871) report this taxon for the Birds of India. It is also mentioned later by Sharpe (1874) in his “Catalogue of the Accipiters, or Diurnal Birds of Prey, in the collection of the British Museum” and so described: “Very similar to C.naumanni, but darker and more vinous red above; underneath also darker-coloured and unspotted when adult. The principal distinction is the wing-coverts, which are almost entirely blue-grey, only the very innermost being slightly washed with rufous. Total length 12 inches, culmen 0-8, wing9-6, tail 5-8, tarsus 1-45. Hab. N: China; Himalayas.” Hodgson (1844, 1845a,b, 1855) mention too the race pekinensis. Hartert (1913) and Hartert & Steinbacher (1933) mention this race as well giving again a description fitting with the original one by Swinhoe and considering valid this taxon (though with some overlapping characters sometimes with the nominate naumanni and reporting some clines). Warren (1966) report :  “Syntype, Adult male. Rea. no. 1886.3.25.272. Near Ming Tombs, north of Peking, 18 Oct. 1868. Collected by R. Swinhoe. Seebohm Collection. Proc. zool. Soc. Lond., 1870 : 442. Also Warren & Harrison (1971, 1973) reported again pekinensis.

More recently, authors has variously faced with the Chinese population from simply ignoring it, to mentioning and describing it as Falco naumanni pekinensis with the given English name of Eastern Lesser Kestrel or synonymizing it with naumanni (lumping together the two taxa): so, for ex. Brown & Amadon (1968) and Brown, et al. (1983) mention among the African raptors also Falco naumanni pekinensis reporting that this race is distributed from Turkestan to northern China, and in Africa it is observed outside the breeding season in Eastern Africa with “Most of the Lesser Kestrels passing through Somaliland appear to belong to this race”. These authors describe pekinensis as so “Adult male differs from the preceding race (naumanni) in having the grey of the wings extending up to the scapulars; secondaries broadly tipped with whitish and a greater amount of blackish on the ends of the primaries. The female and young differ on the latter character only.” Of the same opinion are Etchécopar & Hüe (1967) which report “F.n.pekinensis Swinhoe (Généralment plus gris, sur les moyennes et petites couvertures alaires); Migratrice : Venant d’Asie, accidentelle en Ègypte”. For the Avifauna of China, Etchécopar & Hüe (1978) report again F.n.pekinensis while more recently, Tso-Hsin (1987, 1994) in his synopsis, synonymize pekinensis with naumanni which is reported to be monotypic.  Vaurie (1965) mention Falco cenchris var. pekinensis only as a synonym of Falco naumanni, monotypic. Lesser Kestrel in Asia (Pakistan, South Asia, India, China) is considered monotypic also by Ali & Ripley (1978), Ripley (1982), Inskipp, et al. (1996), Grimmett, et al. (1998) while in the recent Rasmussen & Anderton (2005) no mention at all is given about pekinensis.

Discussion

Was therefore with no clear idea that I went to Tring, the Natural History Museum (NHM) (alongside with my friend and MISC member Ottavio Janni) to check the syntypes of Swinhoe, but eventually what I found were birds clearly different from any Western Lesser Kestrel I knew before. All the specimens labeled as pekinensis preserved into the collections held at Tring and at Almaty Nature Museum of the Zoology Research Institute of the Academy of Science (IZA) show obvious differences to all the other skins of birds collected in the breeding grounds within the Western Palearctic, while some birds collected in the African and even more in the Indian wintering grounds appear indeed similar. I divided the skins into A) birds collected in China during breeding season; B) birds of unknown breeding ground origin, collected elsewhere in Asia; C) birds which are typical naumanni, collected mostly in the breeding grounds of Europe and N Africa; D) birds collected during migration or wintering grounds in Africa, the Middle East and Arabian Peninsula; E) birds collected in India, during migration or winter time.

As shown in the here reported photos, all the birds coming from China (A), most of them labeled originally as pekinensis, show according to the original description of the holotype (called syntype by Warren, 1966 – why?) the whole upperwing coverts grey with also the tertials grey or partially grey. Additionally, the grey tinge is not only reaching the lower scapulars in some birds, but is also of a darker led grey, more sooty (less pure and cold bluish-grey or cerulean-grey), then the birds from Europe (C); on the same way, also the grey on the head and tail is darker and more sooty. The mantle, as correctly reported by Sharpe (1874) is of a deeper and darker vinous rusty-red colour, and the underparts are darker and more satured as well. Birds from other Asian countries (B), such as Kazakhstan, have similarly patterned wing-coverts, though in some birds less extensive and with in most birds part of the lesser and the leading edge rusty tinged (mostly as a rusty “patch” on the inner “harm”), the grey colour of head, tail and coverts being in some not so dark led grey as the Chinese birds (but in some birds being similar) and the underparts appearing less saturated as the mantle less vinous in many birds (but similar in some); indeed, these birds appear intermediate and could be called “cline”. Birds collected in the Middle East, Arabian Peninsula (as in UAE) and Eastern Africa during migration period or winter time have typical plumage (as C) or appear intermediate (as B), but their origin is not known so they could simply be taken into account as “intermediate” birds of unknown origin, while some birds collected in India (E) indeed look like “pekinensis” (as A). On the web and in ornithological books, several birds from India, Arabian Peninsula and Eastern Africa show either an intermediate plumage like birds of the group (B) or a “pekinensis-type” like plumage. The birds from Turkestan, described by Zarudny (1912) as Cerchneis naumanni turkestanicus and reported to have paler plumage than pekinensis with less grey on upperwing but more than on European birds, could be included into the group (B) as intermediate birds of clinal population, while the taxon Cerchneis naumanni sarmaticus (Domaniewski, 1917) is of no taxonomic value at all.

NB: For a comparison study, only birds of the group (A) and (C) could be taken into account, while birds of the group (B) in the middle could only be taken into account as clines or intermediate birds, which are normally found in every subspecies.

From a first and preliminary analysis, it seems that birds of the species’ range show an increasing amount of grey to coverts and saturation in colors moving west to east, with some birds from the Spanish population showing almost no grey on coverts (only a tinges or a tip to the greater coverts), moving east the coverts showing an increasingly wider amount of coverts grey tinged,  almost gradually, as well a more saturated plumage. Therefore, it seems likely that there is a cline in both the extension of the grey on the coverts and the saturation of the pigmentation, with however the Chinese birds being constantly different from all the other Lesser Kestrels and with the differences strongest and most visible. This is only a brief overview of the results obtained and a simple and basic summary, for a better and more in depth treatment see Corso, et al. (in prep.). However, from the preliminary result, not only it seems that the pekinensis taxon is valid, as being readily identifiable and obviously different, but that a genetic study of the Chinese population is surely advisable and should be taken into account (could be that result would indicate something like Red-footed Falcon and Amur Falcon, in the past considered conspecific and often called Western and Eastern RFF ?).

In any case, whatever the validity of pekinensis would be confirmed or not, and accepted or rejected, still the differences in the plumage of the eastern populations should finally be acknowledged and taken into account, as up to date these have never been considered and illustrated in any field guide, handbook or reference dealing with Asian birds in last decades and always Lesser Kestrel has been only depicted with the same wing pattern, therefore with a limited amount of grey on the greater coverts, often hard to be seen in flying birds.

1.Falco naumanni “pekinensis” – adult ♂. Rea. no. 1886.3.25.272. Near Ming Tombs, north of Peking, 18 Oct. 1868. Collected by R. Swinhoe (A.Corso - courtesy of NHM, Tring). Note the entirely led grey wing-coverts and tertials, well contrasting with the white leading edge feathers, the dark sooty led grey hood and the saturated colours of mantle (vinous red) and of the underparts. No illustration in any modern field guide is available of such a plumage, with no description or illustration reporting these characters.  Photo: © A.Corso - courtesy of NHM, Tring

1. Falco naumanni “pekinensis” – adult ♂. Rea. no. 1886.3.25.272. Near Ming Tombs, north of Peking, 18 Oct. 1868. Collected by R. Swinhoe (A.Corso – courtesy of NHM, Tring). Note the entirely led grey wing-coverts and tertials, well contrasting with the white leading edge feathers, the dark sooty led grey hood and the saturated colours of mantle (vinous red) and of the underparts. No illustration in any modern field guide is available of such a plumage, with no description or illustration reporting these characters. Photo: © A.Corso – courtesy of NHM, Tring

2.Falco naumanni “naumanni” – ad. ♂ from Spain. Note that in many European birds the grey on wing coverts is very limited and pretty hard to be seen in the field or even in the hands. Note that the plumage is paler, less intense and deep in both the grey of hood and wing-coverts and of the mantle and underparts. Photo: © A.Corso - courtesy of NHM, Tring

2. Falco naumanni “naumanni” – ad. ♂ from Spain. Note that in many European birds the grey on wing coverts is very limited and pretty hard to be seen in the field or even in the hands. Note that the plumage is paler, less intense and deep in both the grey of hood and wing-coverts and of the mantle and underparts. Photo: © A.Corso – courtesy of NHM, Tring

3.Falco naumanni “pekinensis” – adult ♂ .Note the deeply saturated underparts. Photo: © A.Corso - courtesy of NHM, Tring

3. Falco naumanni “pekinensis” – adult ♂ .Note the deeply saturated underparts. Photo: © A.Corso – courtesy of NHM, Tring

4.Falco naumanni “naumanni” – ad. ♂ from Cyprus, collected in March. Note the very pale underparts typically found in European birds (Western Lesser Kestrel) and compare with the eastern birds. Photo: © A.Corso - courtesy of NHM, Tring

4. Falco naumanni “naumanni” – ad. ♂ from Cyprus, collected in March. Note the very pale underparts typically found in European birds (Western Lesser Kestrel) and compare with the eastern birds. Photo: © A.Corso – courtesy of NHM, Tring

5.Upperparts of F.n.”pekinensis”  to show the very much saturated upperparts. Photo: © A.Corso - courtesy of NHM, Tring

5. Upperparts of F.n.”pekinensis” to show the very much saturated upperparts. Photo: © A.Corso – courtesy of NHM, Tring

6.1 “pekinensis” (leftmost bird) compared with 1 ad. ♂ from Afghanistan and 1 ad. ♂ from Spain, all from Spring, to show the decreasing intensity of the saturation of the grey and the mantle, which in European birds is less vinous-rusty and more terracotta with a pinkish hue.  Photo: © A.Corso - courtesy of NHM, Tring

6. 1 “pekinensis” (leftmost bird) compared with 1 ad. ♂ from Afghanistan and 1 ad. ♂ from Spain, all from Spring, to show the decreasing intensity of the saturation of the grey and the mantle, which in European birds is less vinous-rusty and more terracotta with a pinkish hue. Photo: © A.Corso – courtesy of NHM, Tring

7.Falco naumanni “pekinensis” – 3 adult ♂♂. Note the same typical characters in all three adult males, visibly different from any Western Lesser Kestrel. Photo: © A.Corso - courtesy of NHM, Tring

7. Same birds (above) from below. Photo: © A.Corso – courtesy of NHM, Tring

8.Falco naumanni “pekinensis” – 3 adult ♂♂. Note the same typical characters in all three adult males, visibly different from any Western Lesser Kestrel. Photo: © A.Corso - courtesy of NHM, Tring

8. Falco naumanni “pekinensis” – 3 adult ♂♂. Note the same typical characters in all three adult males, visibly different from any Western Lesser Kestrel. Photo: © A.Corso – courtesy of NHM, Tring

9.Falco naumanni “pekinensis” – adult ♂ compared with an ad. ♂ from Mesopotamia labeled with the trinomial Falco n. naumanni. Photo: © A.Corso - courtesy of NHM, Tring

9. Falco naumanni “pekinensis” – adult ♂ compared with an ad. ♂ from Mesopotamia labeled with the trinomial Falco n. naumanni. Photo: © A.Corso – courtesy of NHM, Tring

Falco naumanni “pekinensis” – adult ♂ compared with an ad. ♂ from Palestine which is labeled with the trinomial nomenclature Falco naumanni naumanni , collected on 1923. Note the differences in saturation and colour tinge/hue of upperparts. Photo: © A.Corso - courtesy of NHM, Tring

10. Falco naumanni “pekinensis” – adult ♂ compared with an ad. ♂ from Palestine which is labeled with the trinomial nomenclature Falco naumanni naumanni , collected on 1923. Note the differences in saturation and colour tinge/hue of upperparts. Photo: © A.Corso – courtesy of NHM, Tring

Close view of the head of same birds of fig.11 to show the grey hood paler in naumanni. Photo: © A.Corso - courtesy of NHM, Tring

11. Close view of the head of same birds of fig.10 to show the grey hood paler in naumanni. Photo: © A.Corso – courtesy of NHM, Tring

Again same birds in lateral view. Photo: © A.Corso - courtesy of NHM, Tring

12. Again same birds in lateral view. Photo: © A.Corso – courtesy of NHM, Tring

13. An adult ♂ Falco n. naumanni (centre) compared with two ad. ♂♂ “pekinensis” from China, to show how much paler pearl grey is the hood and less saturated, less rusty-vinous but more pinkish tinged is the mantle of the Western taxon or form (all Spring birds). Photo: © A.Corso - courtesy of NHM, Tring

13. An adult ♂ Falco n. naumanni (centre) compared with two ad. ♂♂ “pekinensis” from China, to show how much paler pearl grey is the hood and less saturated, less rusty-vinous but more pinkish tinged is the mantle of the Western taxon or form (all Spring birds). Photo: © A.Corso – courtesy of NHM, Tring

Same birds of fig. 13 in lateral view. Photo: © A.Corso - courtesy of NHM, Tring

Same birds of fig. 13 in lateral view. Photo: © A.Corso – courtesy of NHM, Tring

Advanced 2nd cy ♂ (almost in full 1st adult plumage but for retained juv. S1-S2 and growing P10) ringed at Chockpak Bird Station, Kazakhstan, October.  Intermediate bird with a more saturated colour of the plumage than a typical Western Lesser Kestrel and extensive grey panel on upperwing where however a patch of rusty-vinous terracotta is still visible on inner “harm”.  The origin of this bird (breeding ground) is unknown. Photo: © A.Corso

15. Advanced 2nd cy ♂ (almost in full 1st adult plumage but for retained juv. S1-S2 and growing P10) ringed at Chockpak Bird Station, Kazakhstan, October. Intermediate bird with a more saturated colour of the plumage than a typical Western Lesser Kestrel and extensive grey panel on upperwing where however a patch of rusty-vinous terracotta is still visible on inner “harm”. The origin of this bird (breeding ground) is unknown. Photo: © A.Corso

16.Ad. ♂ (with old P10-P8 and S1-S4) ringed at Chockpak Bird Station, Kazakhstan, October.  A bird very much like Eastern Lesser Kestrel Falco naumanni “pekinensis”-type, with a more saturated colour of the plumage than a typical Western Lesser Kestrel and almost wholly sooty led grey upperwing with a slightly visible rusty tinge on innermost “harm” and on scapulars. The breeding ground of this bird is unknown. On a true Chinese “pekinensis” the rusty tinge will be absent or barely visible and in some even the scapulars would be greyish tinged or grey. However, no birds with such a pattern are found in Europe usually and there are no illustration in any modern field guide showing such a plumage.  Photo: © A.Corso

16. Ad. ♂ (with old P10-P8 and S1-S4) ringed at Chockpak Bird Station, Kazakhstan, October. A bird very much like Eastern Lesser Kestrel Falco naumanni “pekinensis”-type, with a more saturated colour of the plumage than a typical Western Lesser Kestrel and almost wholly sooty led grey upperwing with a slightly visible rusty tinge on innermost “harm” and on scapulars. The breeding ground of this bird is unknown. On a true Chinese “pekinensis” the rusty tinge will be absent or barely visible and in some even the scapulars would be greyish tinged or grey. However, no birds with such a pattern are found in Europe usually and there are no illustration in any modern field guide showing such a plumage. Photo: © A.Corso

Acknowledgments

I wish to thanks as always the Tring, NHM staff to which I am much indebted for the most important help for any of my birds plumages studies. So a warm thanks goes to Katrina Kook, Robert-Pries Johanes, Mark Adams and the others working at Tring and that helped me in various way. On the same way, a warm thanks goes to Dr. Carla Marangoni, curator of the ornithological section at Museo Civico di Zoologia in Roma  (MCZR) for the countless hours of help while I was at the museum among hundreds of skins and specimens. Thanks also to the always kind and helpful Anita Gamauf, curator at the Wien Museum (NMW) and to Prof. Andrei Gavrilov who assisted during the skins study at Almaty Nature Museum of the Zoology Research Institute of the Academy of Science (IZA) and thanks to all the curators of all the other museums where I studied the skins collections in all my visits.

Materials

Birds studied in the field:

60.000+ birds  (MM and FF): in Italy, Spain, Greece, Tunisia, Morocco, Egypt, Sinai, France, Greece, Israel, Turkey, Georgia, Kazakhstan.

Birds studied in the hand (combined skins and ringed birds):

(A)“Falco naumanni pekinensis”:  adult ♂. Rea. no. 1886.3.25.272. Near Ming Tombs, north of Peking, 18 Oct. 1868. Collected by R. Swinhoe. For comparison – 40♂♂- from China. (Tring, NHM; Wien, WNHM; Almaty Nature Museum, IZA); birds in the group (E) were not considered for the description of the characters of pekinensis

(B) Falco naumanni ssp. (showing intermediate characters): 75♂♂ ; 27♀♀ – Kazakhstan, Azerbaijan, Turkmenistan.

(C) Falco naumanni  (typical plumage): 270♂♂ ; 82♀♀  – coming from Spain, Italy, Greece, Tunisia, Morocco, Albania, France;

(D) Falco naumanni (both typical naumanni and intermediate birds): 79♂♂ ; 90♀♀  – Turkey, Israel, Egypt, Senegal, Niger, Mauritania, Iraq, Iran, Tanzania, Syria, Lebanon, Jordan, Palestine,  Kirgizstan, Slovenia, South Africa, Check Republic, Georgia.

(E) Falco naumannipekinensis-type”: 10♂♂ from India.

Skins studied preserved at the following museums: Natural History Museum, Tring, England (NHM); Institute of Zoology, Almaty, Kazakhstan (IZA); Museo Civico di Storia Naturale di Milano, Milan, Italy (MCSM); Museo Civico di Terrasini, Palermo, Italy (MCT); Museo Civico dell’Università di Scienze Naturali di Catania, Catania, Italy (MCUCT); Museo Civico di Zoologia di Roma, Rome, Italy (MCZR); Museo Regionale di Scienze Naturali di Torino, Torino, Italy (MRSN); Museo di Storia Naturale “Giacomo Doria”, Genova, Italy (MSNGD); Museo di Storia Naturale “La Specola”, Firenze, Italy (MSNLS); Museo Civico di Storia Naturale di Carmagnola (); Museo Civico di Scienze Naturali “Angelo Priolo”, Randazzo, Italy (MCR); Naturhistorisches Museum Wien, Vienna, Austria (NMW); Nationaal Natuurhistorisch Museum Naturalis, Leiden, the Netherlands (NNM).

References

Ali, S. & S.D. Ripley, 1978. Handbook of the Birds of India and Pakistan. 9: i-xvi, 1-306.— Bombay.

Brown, L. H., and Amadon, D., 1968. Eagles, Hawks and Falcons of the World, vol.1 and 2. Country Life Books, London.

Brown, L. H., Urban, E. K.& Newman, K. 1982. The Birds of Africa. Vol. I. London, UK: Academic Press.

Cheng, Tso-hsin, 1987. A synopsis of the Avifauna of China. i-xvi, 1-1223.— Beijing.

Cheng, Tso-hsin, 1994. A complete checklist of species and subspecies of the Chinese birds. i-xx, 1-

318.— Beijing.

Clark W.S., 1999. A Field Guide to Raptors of Europe, The Middle East and North Africa. Oxford University Press, Oxford.

Corso A., 2000. Less is More: British vagrants, Lesser Kestrel. Birdwatch 91: 29-33.

Corso A., 2001. Notes on the moult and plumages of Lesser Kestrel. British Birds 94: 409-418.

Cramp S & Simmons K.E.L. eds., 1980. The Birds of the Western Palearctic. Vol. 2: Hawks to Bustards.  Oxford University Press, Oxford.

Domaniewski J., 1917: Przyczynek do znajomości form geograficznych Cerchneis naumanni (Fleisch.) [A

contribution to the knowledge of geographic forms of Cerchneis naumanni (Fleisch.)]. – Comptes Rendus

de la Société des Sciences de Varsovie 10 (9):1043-1047. [In Polish.]

Etchécopar, R. D. & Hüe, F., 1978. Les oiseaux de Chine, de Mongolie et de Corée – Vol. I, Non passereaux. Papeete, Tahiti,  Éditions du Pacifique.

Etchécopar, R. D. & Hüe, F. 1964. Les Oiseaux du Nord de l’Afrique, de la Mer Rouge aux Canaries. Paris, France: Editions N. Boubée & Cie.

Ferguson-Lees J. and Christie D.A., 2001. Raptors of the World. Christopher Helm, London.

Forsman D., 1999. The Raptors of Europe and the Middle East. A Handbook of Field Identification. L.T & A.D. Poyser, London.

Grimmett, R., C. Inskipp & T. Inskipp, 1998. Birds of the Indian Subcontinent. 1-888.— London.

Hartert, E., 1913. Die Vögel der paläarktischen Fauna, Heft VIII- p.1081.

Hartert, E. & F. Steinbacher, 1933. Die Vögel der Paläarktischen Fauna. Ergänzungsband. 2: 97-192.— Berlin.

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Miscellany: 81-86.

Hodgson, B.H., 1845a. Characters of six new species of Nepalese birds.— Ann. Mag. Nat. Hist., (1) 15 (99): 326-327.

Hodgson, B.H., 1845b. [On Nepalese birds.].— Proc. Zool. Soc. Lond.: 22-37.

Hodgson, B.H., 1855. Catalogue of Nipalese Birds, collected between 1824 and 1844.— J. Asiatic Soc.

Bengal, 24 (7): 572-582.

Jerdon,T. C., 1871. Supplementary Notes to ‘The Birds of India’. Ibis 13: 335–356.

Inskipp, T.P., N. Lindsey & J.W. Duckworth, 1996. An Annotated Checklist of the Birds of the Oriental

Region. [i-x], 1-294.— Sandy, Beds., UK.

Rasmussen, P. C. & Anderton, J. C., 2005. Birds of South Asia: the Ripley guide. Barcelona, Lynx Editions.

Ripley, S.D., 1982. A synopsis of the birds of India and Pakistan together with those of Nepal, Bhutan,

Bangladesh and Sri Lanka. i-xxvi, 1-653.— Bombay.

Sharpe, R.B., 1874. Catalogue of the birds in the British Museum. I. Catalogue of the Accipitres or diurnal birds of prey in the collection of the British Museum.— London, Taylor & Francis.

Snow D.W. & Perrins C.M., 1998. Birds of the Western Palearctic: concise edition. Vol 1 – Non-Passerines. Oxford University Press, Oxford.

Swinhoe, R., 1870. Zoological notes of a journey from Canton to Peking and Kalgan.— Proc. Zool. Soc.

Lond.: 427-451.

Swinhoe, R. 1871. A Revised Catalogue of the Birds of China and its Islands, with Descriptions of New Species, References to former Notes, and occasional Remarks. Proc. Zool. Soc. Lond.: 337-423.

Vaurie, C., 1965. The Birds of the Palearctic Fauna. A systematic reference. Non-Passeriformes: i-xxi, 1-

763.— London.

Zarudny, N.A., 1912. On the Ornithology of Turkestan – Urinator arcticus suschkini and Cerchneis naumanni turkestanicus subspp. nov. Ornithologische Mitteilungen : 114.

Warren, R.L.M., 1966. Type-specimens of birds in the British Museum (Natural History). 1: i-x, 1-

320.— London.

Warren, R.L.M. & C.J.O. Harrison, 1971. Type-specimens of birds in the British Museum (Natural History).

2: i-vi, 1-628.— London.

Warren, R.L.M. & C.J.O. Harrison, 1973. Type-specimens of birds in the British Museum (Natural History).

3: i-xii, 1-76.— London.

–          APPENDIX I

LESSER KESTREL NOMENCLATURE  (synonym)

FALCO NAUMANNI  (Fleischer, 1818)

–          Falco naumanni [as Naumanni] J.G.Fleischer, 1818 – in Laurop & Fischer, Sylvan. Ein Jahrbuch für Forstmänner,Jäger und Jagdfreunde auf das Jahr 1818, p.174. (“spärlicher Gast im südl. Deutschland und Schweiz”; error for Sicily, fide Stresemann (MS))

Falco xantonyx [as Xantonyx] J.G.Fleischer(ex Natterer MS), 1818- in Laurop & Fischer, Sylvan. Ein Jahrbuch für Forstmänner, Jäger und Jagdfreunde auf das Jahr 1818, p.175. (= F.naumanni)

Falco tinnunculoides Temminck (ex Natterer MS) (1820) – Manuel d’ornithologie, ou Tableau systématique des oiseaux qui se trouvent en Europe…,2nd edn,1,p.30. (“Hongrie,Autriche-Naples-Sicile-Sardaigne-Espagne”). (= F.naumanni)

Falco cenchris Frisch (1820) – in J.F.Naumann, Johann Andreas Naumann’s mehrerer gelehrten Gesellschaften Mitgliede, Naturgeschichte der Vögel Deutschlands ,2nd edn,1,p.318,pl.29. (Italy,Austria,Tyrol,Switzerland,Savoy,Piedmont).

Falco xanthonyx Naumann (ex Natterer MS) (1822) – Johann Andreas Naumann’s mehrerer gelehrten Gesellschaften Mitgliede,Naturgeschichte der Vögel Deutschlands…,1,p.323. (= F.naumanni)

Falco tinnuncularius Roux,1825 – Ornithologie provençale;ou description…de tous les oiseaux qui habitent constamment la Provence,ou qui n’y sont de passage,1,p.60,pls.40,41. (Provence). (= F.naumanni)

Falco subtinnunculus C.L.Brehm (1827) – Ornis,3 Heft,p.12. (Egypt and southern European islands). (= F.naumanni)

Cerchneis cenchris C.L.Brehm (1831) – Handbuch der Naturgeschichte aller Vögel Deutschlands,p.74. (= F.naumanni)

Tinnunculus cenchris Bonaparte (1842) – Catalogo Metodico degli Uccelli di Europa, p.21. (= F.naumanni)

Tichornis cenchris Kaup (1844) – Classification der Säugethiere und Vögel,p.108. (= F.naumanni)

Poecilornis cenchris Kaup, 1850 in W.Jardine(ed.) – Contributions to Ornithology for 1850,p.53. (= F.naumanni)

Cerchneis paradoxa C.L.Brehm, 1855- Der Vollständige Vogelfang,p.29. (Greece). (= F.naumanni)

Cerchneis ruficeps C.L.Brehm,1855,Naumannia, p.269. (= F.naumanni)

Cerchneis ruficauda C.L.Brehm,1855, Naumannia, p.269. (= F.naumanni)

Erythropus cenchris Jerdon , 1862 – The Birds of India, 1, p.38. (= F.naumanni)

Falco naumanni naumanni – Hartert,1913 [“1921”], Die Vögel der paläarktischen Fauna,Heft VIII(Aug.),p.1080. (= F.naumanni)

Cerchneis naumanni  – Sharpe (1874) – Catalogue of the Birds in the British Museum,1, Accipitres or Diurnal Birds of Prey, p.435. (= F.naumanni)

Falco cenchris var. pekinensis Swinhoe (1870). Proceedings of the Zoological Society of London,p.442. (near Peking).(= F. naumanni pekinensis)

Tichornis pekinensis Swinhoe (1871). Proceedings of the Zoological Society of London,p.341. (= F. naumanni pekinensis)

Cerchneis pekinensis in Sharpe (1874). Catalogue of the Birds in the British Museum,1, Accipitres or Diurnal Birds of Prey,p.437. (= F.naumanni pekinensis )

Erythropus pekinensis in Jerdon (1871). Ibis,p.242. (= F.naumanni pekinensis)

Falco naumanni pekinensis Hartert 1913 [“1921”], Die Vögel der paläarktischen Fauna, Heft VIII(Aug.),p.1081. (= F.naumanni pekinensis)

Cerchneis angolensis Bocage, 1876 – Jornal de Sciencias mathematicas,physicas e naturas, publicado sob os auspicos da Academia real das sciencias da Lisboa 5: 153. (Huilla in Angola). (= F.naumanni)

Cerchneis naumanni turkestanicus Zarudy, 1912 – Ornithologische Mitteilungen, p.114. (= F.naumanni ssp.)

Cerchneis naumanni sarmaticus Domaniewski, 1917 – Compt. Rend. Soc. Sci. Varsovie, X, p. 1044. (= F.naumanni)

Eastern Common Tern – did one frequent Minsmere in 2011?

Eastern Common Tern – did one frequent Minsmere in 2011?

By David H Hatton, Royston, Herts, UK

In the late spring of 2011, I took a holiday based at Westleton, Suffolk, for a week together with fellow birding friend Tim Wilson and our families. Most days we would venture the short distance to Minsmere RSPB reserve for some birding and photography. During the course of these visits, we had encounters with many terns, but one in particular may be exceptionally interesting.

On the 30 May at 8.50 am Tim spotted an adult dark-billed tern resting some 40 metres from the south hide. Presuming it was going to be one of the few Roseate Terns present we switched to our scopes only for it to immediately fly off over the scrape and disappear seawards. In flight, the jizz looked wrong, lacking the long tail expected of that species. And, as Tim pointed out, shouldn’t it have had bright red legs?! – as his first brief binocular view had indicated the bird possessed dark legs, we scratched out heads and mused over whether a 1st or 2nd summer ‘portlandica’ Common Tern might be the explanation.

Later that week, on the 3rd June at 8.10 am, I was alone in the east hide at the end of a pre-breakfast walk down from Dunwich cliffs. Scanning the scrape, a tern suddenly grabbed my attention, sitting on one of the perching poles conveniently located to the left of the hide. Again I fell for the same trick – with my eyes briefly feasting on the black crown and bill, ‘great, Roseate’ I thought to myself as I instinctively switched to my digiscoping set-up and spent a few seconds slotting the gear over the eyepiece. The very moment the target snapped into focus, and before I could press the shutter button – it took off and started flying towards me. This time, I reached for my SLR and, with some relief, it locked on, allowing a couple of shots to be acquired (Figs 1, 2). Seconds later, the bird had passed the end of the hide and disappeared over the dunes towards the sea.

Again I was to be initially disappointed – its dusky not pinkish underparts, modest tail, rather ‘common’-like underwing pattern, with pale semi-translucent inner primaries contrasting with dark-tipped outer primaries and slightly darker grey secondaries, all suggesting Common Tern, Sterna hirundo. However, really bamboozling me was its quite un-‘common’-like bill – modest in length, delicate in structure and entirely blackish along its length save a hint of maroon at the very base of the lower mandible. Its completely black cap and neat body plumage suggested it was in adult summer plumage, but why that funny bill?

With some photographic evidence acquired and the end of the family holiday approaching, I resolved to follow it up later. I was likely to be stymied I thought by the brevity of my encounter and lack of detailed field notes, but, within days of my return, and with excellent timing, I noticed Sean Nixon’s account and photos that had just been published in Birding World (issue 293), of a presumed ‘Eastern Common Tern’, S. h. longipennis, at, where else but, Minsmere on 14 May 2011, putatively only the second record for Britain of this form. Until that point, I had forgotten about the existence of these birds that, unlike European birds, are black-billed in summer. That article, with its insightful additional editorial analysis, together with an update six months later (issue 300), arguing that a second bird was present at Pakefield (& possibly Alton Water), Suffolk 14 July 2011 and another, perhaps third bird, present at Heist, Belgium on 22 June 2011, convinced me that I should seriously consider whether I had fortuitously added a piece to the jig-saw of Suffolk ‘Eastern CT’ occurrences in 2011.

Below I tabulate the known features of Eastern Common Tern (believed to be useful for separation w.r.t. Common Tern) and compare them with the set of features of the ‘East hide’ bird. This summarizes information I have found published in Birding World issues 293, 300 & 303, Terns of Europe & North America (Olsen & Larsson, 1995) and the Advanced Bird ID Guide (N.v. Duivendijk, 2010).

Eastern Common Tern features in comparison with those of Common Tern (adults) Minsmere ‘East hide’ bird, 3 June 2011Similar feature present?
Slightly more svelte appearance YES, the bird was more elegant & less ‘stocky’ to my eyes, born out by the side-view photo
Smaller more domed head/crown YES, head neatly domed, less angular than CT
Slightly longer wings, outer tail feathers project slightly beyond wing-tips Not determined
Bill shorter & finer, sharper, less dagger-shaped (though some variability) YES, bill less ‘dagger’ proportioned appearing fine in side view
Bill black, some with crimson-purple at base of lower, brightening in spring YES, blackish, with small area of blackish crimson at base of lower mandible
Bill has less arched culmen YES, bill has quite delicate profile
Black crown has more sharply defined edges, sharper contours behind head YES, sharply demarcated edges to whole crown
Dark trailing edge to secondaries on underwing YES, grey distal secondary band contrasting with white greater coverts
Upperparts more ash grey Not determined, but perhaps hinted at by darkness of the underside secondary band
White cheek stripe, esp. in front of eye YES, contrasting moderately with pale grey upper breast
Underparts dusted with lavender grey, isolating a white cheek stripe YES breast & belly looked darker and more contrasty than other CTs seen in same light
Legs dark reddish brown/brown/chestnut Legs retracted & invisible in flight, not noted either way when briefly perched
Call less shrill Not determined (silent)

I conclude that the East hide bird of 3 June 2011 shares many of the features associated with Eastern Common Tern, especially the overall jizz and bill colour and structure, although the character set is incomplete because views of the upperparts and leg color were not obtained. No strong contra-indicatory features were noted. Could a ‘western’ Common Tern in summer ever show such a suite of features one wonders? The photos I obtained are not inconsistent with those published in plates 1–3 and 10 of Birding World issue 293 (pp. 211, 214) – if it is an Eastern type, perhaps the bird that Sean Nixon found was more than a one-off visitor to Minsmere in spring of 2011 – maybe it will return!

Acknowledgements

I thank Tim J. Wilson and Charles Fentiman for discussions during preparation of this note.


www.art16.co.uk

20 Apr 2012

Footnote –  See similarity from BirdQuest in Japan:

http://www.birdquest-tours.com/gallery.cfm?TourTitle=&start=3206