Friday, 30 November 2012

More Little Owls at Manor Farm - 29th November 2012

With the weather set fair, the sky clear and no wind it was off to Manor Farm for a spot of nocturnal bird ringing. In previous years this time of year has proved to be an ideal time to catch little owls, so we set our nets and waited. A barn owl was screeching as we put the nets up, and a tawny owl called in the distance, but otherwise it was quiet. A stroll around the fields produced a couple of calling lapwing, and then it was back to the nets and.......a little owl.

Juvenile Little Owl

During previous nocturnal ringing sessions at Manor Farm we have had mixed success, and have so far ringed five new birds and retrapped one; in 2011 three new birds were ringed, this year one of last years birds has been retrapped, until last night that is. 

Little Owl wing showing Juvenile Primary Coverts

According to Baker (1993) Identification Guide to European Non-passerines, juvenile little owls undergo a partial moult, that starts soon after fledging and is confined to the head, body lesser and median coverts. However, adult birds undergo a complete post breeding moult that usually starts as early as June or July and continues through to September or October, occasionally November.

Juvenile Primary Coverts

This bird was evidently a juvenile since it had moulted the majority of its wing coverts with the exception of the primary coverts and some feathers in the crown and nape. The difference in the shape of the primary coverts and their colouration can be seen in the two images above.

Pointed Tips to Primary Coverts

Another feature of juvenile birds is the shape and patterning of the outer-most primary, in juvenile birds this feather is pointed with a white tip to the inner and outer webs. In adult birds the outer-most feather is rounded at the tip with the outer web only, showing a white tip. Interestingly, this bird did not show a white tip to the inner web of the outer-most primary, but the tip of the feather was still pointed, therefore it is worth being cautious with this feature.

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