• Vincent

25 December. Boxing Day! Rinse and I don't need much time to think when were asked to ring a few birds in bird hospital De Wulp. The star of the day is a Black-necked Grebe.

The poor bird has been bitten in the neck by something, probably a dog. It's recovering fast, but it still needs some time before it can be released. But leave that to the ladies!

Ageing is based on two features. The pale orange iris indicates a young bird; I'd expect a more reddish iris in an adult (see here).

More importantly are the juvenile scapulars, that are obviously still brown instead of black. So yes, this is a young bird (1 cy). Apparently this is only the 14th Black-necked Grebe ever to be ringed in the Netherlands.

It reminded me of the Slavonian Grebe we ringed here back in 2013. Ageing works the same way as in Black-necked. This bird had a red iris, but this was in February - nearly three months later.

There wasn't much contrast in the wing of today's Black-necked:

But brown, juvenile feathers (e.g. the greater coverts) were found in the wing of the Slavonian at the time:

So this too was a 1st winter. I remember it was in great shape: it only got disorientated by lights during the night and therefore ended up at the wrong place (it flew into a building and couldn't get out). It was released straight after the health check: there was no need to keep it inside any longer.

After we ringed the brebe, it became clear only star birds were available, with Guillemot, Razorbill and Kingfisher also ringed. And a lovely Red-throated Loon that frequently uttered a wailing alarm call. Rinse knew this call from the nesting sites in the arctic, but at least it did manage to impress me:

#BlackneckedGrebe #RedthroatedLoon

Right. Chiffchaffs never stop to amaze me. But I now feel we're really getting somewhere.

Only very recently Peter de Knijff and I wrote something about Siberian Chiffchaff look-alikes on this site. The upper bird in that little web article looked like a tristis, but IMHO it was not an exact copy. Something looked off. So I ringed it as a Common Chiffchaff, without specifying the ssp.

More significant is that it called dozens of times, just before I released it. And it called like a Common Chiffchaff collybita/ abietinus.

The spectogram also shows a perfect match for Common, with an upward inflected call:

I did ask Peter to look carefully at the feather material I collected. Now Peter's mtDNA analyses came in: tristis. Yes, this bird with a hueet call shows tristis mtDNA!

Fairly recently they had a similar case in the UK, see here (scroll a few pics down) and here.

In 2018 Peter and his students will run a second test on all tristis we've trapped at five sites over the past five years. In this second test we'll try to figure out if any introgression with abietinus can be found. This will hopefully give new insights into stray Siberian Chiffchaffs in NW Europe. And in this individual - hopefully!

To be continued!

(I will add this web post as a post scriptum to the afore mentioned web article about look-alikes).

#mtDNA #geneticanalyses #SiberianChiffchaff #CommonChiffchaff #tristi #abietinus

  • Vincent

I've got a thing for Iceland Gull. There's just something about 'm! Something Glaucous Gull for instance misses. Like there's something about Caspian Gull that's missing in Yellow-legged.

In 1992, as a young teenager, I saw my first IG on my local winter patch: the harbour of Scheveningen. In the Netherlands, Scheveningen is Iceland Gull capital.

Now, 25 years later, I saw my 25th one for the site (see pic on top of this post). A milestone (thanks Wim). Who would have thought back in 1992? Until 1997 Iceland Gull even had to be submitted to the Dutch rarity committee!

22 of these birds were 1st winters (calling them juveniles would be more appropriate). I haven't seen a single 2nd winter in Scheveningen (though I have seen it elsewhere). The first IG I found myself wasn't until 2004. Now I've found at least six. Remarkably I found all of the (sub)adults I saw myself.

I think back at the thrill the adult caused that flew past me in January 2012. I started looking for it to get another view, and finally got another fly by. Or so I thought. When I checked my photographs it appeared that I first photographed a 3rd winter and then found a true adult an hour later!

I think about the another adult in December 2013. When it got closer the thrill got even bigger: it turned out to be the 3rd Kumlien's Gull for the Netherlands (pic below).

However, nothing beats early 2017, when an unprecedented influx of white-wingers hit our coast. Amongst at least 12 (but probably more) Glaucous, we identified no less than 8 Iceland Gulls (of which I saw 7), with up to 6 birds present at the same time.

But most of all, in these 25 years, I've learnt how wonderfully variable the young birds are. Some are very white, others are quite dark, some are a bit smudgy (2nd pic of this post!), some pretty big, others incredibly neatly patterned and so slim that they reach esthetical perfection (see below!).

Iceland Gull is clearly on the increase. I hope it won't take another 25 years to hit the 50 mark.


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Arnhem AEB413

18 October 2014, Meijendel, Wassenaar, the Netherlands

© 2018 by Vincent van der Spek