April 23, 2007

mid-APR 2007, Tsetserleg - K. Schleicher
On 15 April I observed for the second time a White-backed Woodpecker which was pecking at the inside of a cracked bone in the city park of Tsetserleg (compare pictures from 29 March). After the woodpecker finished searching for food I examined the bone. There was fresh marrow in it with traces of the woodpecker’s bill, proving that the woodpecker(s) are specialised in feeding on marrow.

New spring arrivals around Tsetserleg were: 12 Apr 1 Booted Eagle (dark morph). Last year Booted Eagle bred successfully in mountain forest two kilometres north of Tsetserleg. 13 Apr 1 Pied Wheatear (singing) and Black Redstart (ssp. P. o. phoenicuroides; singing). 14 Apr 2 Mongolian Gulls resting on the ice of Tamir river. 15 Apr, at the wet area adjacent to the airport: 2 Eurasian Rooks, 2 Citrine Wagtails, 4 Common Starlings, 12 Mallards, 2 Bar-headed Geese, and 1 male Common Teal.

Booted Eagle. Photos © K. Schleicher

I have to withdraw the record of 31 Eurasian Jackdaws from 9 April. A closer look through the telescope on 15 April revealed that at the same site only Daurian Jackdaws in first-winter plumage were present. Their number had increased to c.1,500. I had mistaken these dark birds for Eurasian Jackdaws.

Comment by Axel:
Daurian Jackdaw has three distinct plumages: juveniles and adults are pied, while first-years are largely black. The variation in head streaking of first-years, often mentioned as a key separation feature from Eurasian Jackdaw, is related to time of year. One consequence of that may be that first-winter Daurian Jackdaws are often confused with Eurasian Jackdaws.

First-winter Daurian Jackdaws which lack streaking on the ear-coverts closely resemble juvenile Eurasian Jackdaw. They are, however, readily separable from first-winter and adult Eurasian Jackdaw by their lack of a pale grey nape. In addition, first-winter Daurian Jackdaw has a glossy back throat which contrasts with the sooty-black upper breast. Furthermore, the iris colour is always dark in Daurian Jackdaw, but ranges between light grey and white in Eurasian Jackdaw. This last difference is diagnostic at all ages, except for recently fledged juvenile Eurasian Jackdaws, which have dark irides.”
from: Leader, P. J. 2003. Identification of Daurian Jackdaw. British Birds 96: 520 - 523

I checked several Daurian Jackdaws flocks, often consisting of hundreds of birds, in Ulaanbaatar on 16/17 April 2007. The percentage of adult birds in these groups was mostly 1-2% only; the majority were birds in first-winter plumage.

Daurian Jackdaw, adult. Ulaanbaatar, 16 April 2007.
Photo © A. Braunlich

Daurian Jackdaws, first-winter plumage.
Ulaanbaatar 16 April 2007. Photo © A. Braunlich

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