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recent updates: citrine wagtail calls and hybrid redstarts

Two new articles are added to the site!

Citrine Wagtail ID: do flight calls tell us which subspecies is involved?

Could calls shed some light on the subspecies that reach NW Europe as vagrants? Maarten Wielstra collected a team of people to work on an analyses to find out if the calls of various ssp. differ on their breeding grounds. See more here.

Hybrid redstarts in Europe and North Africa: an analyses of 121 hybrids

Nicolas Martinez, Bern Nicolai and I wrote a British Birds paper on redstart hybrids. A summary of the analyses can be found here.

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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