Redstart hybrids in Europe and North Africa

Nicolas Martinez, Bernd Nicolai & Vincent van der Spek

- Published in British Birds 112 (April 2019)

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Abstract
An analysis of 121 wild Black Redstart
Phoenicurus ochruros x Common Redstart P. phoenicurus hybrids from Europe and North Africa is presented, with an overview of distribution, phenology, habitat, biometrics, phenotypes and vocalisations. Records of hybrid redstarts have increased markedly over the past 30 years. Such birds show an intermediate phenology but in terms of habitat choice are more similar to Black Redstarts. No wild female hybrids were found, which must be related to reduced detectability. The locally more abundant species usually plays the role of the female in mixed pairs and in pairs with male hybrids. Plumage variation within male hybrids is higher than previously documented. Primary spacing ratio and the presence of emarginations on P6 are useful identification features for hybrids, but there is substantial overlap with both parental species, and with ‘Eastern Black Redstart’, especially P. o. phoenicuroides. Song of hybrids may approach Black Redstart in structure and presence of the ‘scratchy’ part, but matches Common Redstart in pace and strophe length.

Article available on request

Male hybrid Black Redstart x Common Redstart (foreground) with male Black Redstart, Wyhlen, Germany, 31st March 2012. This hybrid was seen in a flock of no fewer than 153 Black Redstarts (Daniel Kratzer)

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