The Little, Rare Ones
by Martin G.
two themes running through some present posts. The glorious Spurn Migration Festival (YES – I really want you to be there– (there is such high praise for the enjoyment so many folk get out of the migfest weekend). The second theme is on the Saturday evening talk at the Festival. Delivered by the hugely respected, and mega keen Yoav Perlman, it will be sure to open some eyes and be full of WOW factors.
One subject I have explored with Yoav are some of the curious and bewildering hirundines which pass, on migration, through Israel. It’s timely because…. when you visit Spurn, early September is the peak time for hirundine migration– Swallows and Martins.
Spurn and Sand Martins
As a warm-up here’s some stats from the (soon to be published) ‘The Birds of Spurn’ by Andy Roadhouse.
“Sand Martins generally have two broods, and this is shown with the autumn passage at Spurn. Two ‘waves’ of passage occur, the first from late June to early August and the second from late August to mid-September. In the earlier days of the Observatory the first wave would have largely gone unrecorded due to the lack of observers in the summer months. The highest counts in the first wave are 2800 on 5th August 1984, 2000 on 17th July 1999 and 15th July 2008. There is one exceptional count of 12,000 on 22nd August 1996, otherwise high counts in the second wave are 3000 on 28th August 2000, 2500 on 3rd September 2003 and 2000 on 20th August 1996.”
Our Sand Martins (nominate riparia)
You’ll see Sand Martins migrating at the festival- For sure! Here a couple of nominate Sand Martins trapped and ringed at Spurn (by Adam Hutt). Before rushing forward to the enigmatic eilata, check out the throat, breast band and overall head pattern of our Sand Martins. This is one has a tiny bit of streakiness on the throat sides.
Enigmatic eilata – ‘Little’ Sand Martins in SPRING
The ringing station at Eilat provides one of the most thrilling migration encounters in the world. Hidden away under the wonderful colour and variety of bird species passing through the area is a ‘little brown job’. Trapping hirundines coming into roost in the evening proved the best opportunity of seeing an ‘eilata’ Sand Martin. The taxon was first recorded by Hadoram Shirihai and written up in Shirihai & Colston, (1992). (Though I don’t think diluta ‘Pale Martin’ passes through Israel as suggested in the article- just part of the learning).
I was fortunate with a little effort to see several individuals of eilata in early spring 2012.
They are tiny! Compared with nominate riparia Sand Martins they are slightly colder and paler brown with a much shorter wing length (over 100mm in nominate riparia). The eilata featured here had a wing length of 94mm. Other features included feathered tarsi and slightly more contrastingly dark lores: ‘sunglasses’.
Curiously neither the breeding nor wintering areas are known, nevertheless they represent up to 5% of the Sand Martins passing through Israel in spring.
Enigmatic eilata- ‘Little’ Sand Martins – in summer
This spring Francis Argyle was ringing Sand Martins in the Hula Valley. He trapped several ‘tiny Sand Martins’. A very small percentage among nearly 2000 nominate riparia. They were in juvenile plumage (age 3 for ringers). Francis writes:
“This spring, 20th March to 24th May, I have ringed 1990 Sand Martins. I ring in 4-day sessions of which three per month.7th to 10th May, 893 Sand Martins ringed of which only 1 tiny age 3 bird. 21st to 24th May just 1 tiny out of 379. 2nd to 5th July only 4 Sand Martins caught and all 4 were small age 3 birds although one had a wing length 105mm.
These juveniles have much more patterning over the throat, sometimes looking more like a Brown-throated Martin (paludicola). From the very small sample of apparent juvenile eilata most of them had fringes to wing coverts closer to ‘silvery’ than ‘gingery-buff’. On passage birds at Spurn, gingery -buff os the normal type of juveniles with just occasional silvery ones. We blogged about there >>>HERE<<<.
Here’s what the apparent juvenile eilata look like. All photos by Francis Argyle.
Francis collected a couple of feathers and with help from Yoav and the Prof (Martin Collinson) a very preliminary look said these were pretty bloomin’ well closely related to other Sand Martins. There are still plenty of questions though…
“I have some preliminary results on the small Riparia riparia feather from Hula Valley, 20/5/15 (X264997). I put it through with a batch of cytb sequencing – there is only 1 cytb sequence for this species in GenBank – a bird collected in S Africa and therefore of unknown subspecies. Your bird is 99.4% identical to that one, i.e. very closely related.
Looking in the literature, although eilata has not been sequenced, COI and ND2 data suggest very little genetic differentiation (0.6%) between Sand Martins across the range, in US/Canada, Europe, through to East Asia, suggesting gene flow until very recently, and your bird fits with that general pattern.
Really , really hope to see you at the Migration Festival. You won’t regret it!
……………………….To book go >>>HERE<<<