• Vincent

Hume's Leaf Warbler: my bird of the autumn


Autumn 2016 was nothing less than perfect. But this autumn, well... it was a bit boring to be honest. I missed most good vis mig days, ringing was often impossible due to unfavourable weather, and I hardly saw anything notable in the field. The Hawfinch an Parrot Crossbill invasions were the rare highlights.

But since November, things seem to have changed a bit. A self-found Richard's pipit that performed well was an omen. And I found the motivation to go ringing again. And while I enjoyed ringing the common species, I started trapping interesting birds, like Jack Snipe, Long-eared Owl and Siberian Chiffchaff.

And then, on 7 November I got my star bird of the autumn: a lovely Hume's Leaf Warbler (pic on top of this page by Noël Aarts). I've been lucky enough to have found them in the field twice before, but it was a new bird for me in the hand!

The ID was more or less straight forward. See the differences with Yellow-browed below (please not that not all Hume's are so easy to tell apart from YB on plumage).

A= Note Yellow-browed Warbler (YBW) has a clear dark shade on the secondaries, below the (2nd) wingbar. This is nearly absent in Hume's Leaf Warbler (HLW)

B= YBW has a clear upper wingbar on the median coverts, in HLW this is often absent or faint

C= HLW has greyish green upperparts, vs. moss green in YBW

D= Note that YBW (hence the name!) has a yellow in the supercilium, whereas it's buff in HLW

E= YBW usually has a faint crown stripe

F= "Dirty", green streaked cheek in YBW vs. cleaner, pale cheek in HLW G= Note cleaner, whitish underparts in HLW vs. often yellow streaks in YBW

A= Edges of primaries and secondaries greenish on YBW, buff on HLW B= Note yellowish tone on tips of greater coverts in YBW, vs white in HLW

C= Primary coverts with brownish grey edges in HLW, vs. greenish in YBW

D= Obvious pale edges on median coverts in YBW forming an obvious 2nd wingbar; brownish buff on this HLW only creates a faint one

In YBW the legs are usually orange, or at least the toes and soles.

This is only the 6th to be ringed in The Netherlands (on little over 60 records) and the first for our ringing site in Meijendel, Wassenaar, The Netherlands (since 1927, the oldest ringing site in Holland!).

#birdringing #rarities #HumesLeafWarbler #identification

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Little Bunting
The most interesting thing about this chapter is the sexing of birds. This could be done on the basis of lateral crown stripe: a new feature for me. Because of overlap between adult females and young males, birds should first be aged. The authors emphasize that this is their vision, and not necessarily the final answer to this matter. I found one in the field in October (Figure 4-5) of which I took reasonable pictures. The very rounded tail feathers look adult, as do the tertials and large coverts. The lateral crown stripe appears to be jet black and is separated from other feathers, such as the greyer back of the head. The orange-red crown stripe really stands out. Conclusion: according to this book this must be an adult male! The deep brown-red cheek - a variable feature according to this book - also fits that. So it works then? Well… how useful this really is, remains the question: based on this book I would label two "females" in Shirihai & Svensson (p546 both top right and bottom right) as males! The caption of one of these even mentions "safely identified as a female" because it has a relatively dull plumage for an adult bird. But is also has a jet black, strongly separated lateral crown stripe! The bird at the bottom right even has a pretty deeply coloured cheek, which I would be happy to call a male. Is this due to different insights, and if so, who should I believe? Or am I not interpreting this correctly? In any case, it is fascinating!

© 2018 by Vincent van der Spek