Monday, December 20, 2010

Continental cousins

Since the snow there has been a bit of an influx of Blackbirds. Idly watching them, it was soon apparent how variable they could be, particularly the females. I then had this idea of trying to photograph all visitors with an aim to see how many individuals I could identify. I didnt really have that much spare time but was soon caught up in the moment as more and more seemingly different birds arrived. Over the course of about a one and a half day period I made frequent trips to the window. At any one time the maximum count was 8 birds together but it turned out that there were at least 18 individuals.

It was also apparent how many infact showed these chevrons I mentioned on 2nd Dec, ie characteristics of the continental birds

I dont really know a great deal about Blackbirds, their variation and their moult but have attempted to make some sense of the individual birds.

According to BWP adult birds go through a complete post breeding moult and should be finished by November. Juveniles only undergo a partial moult and so will show contrasting old and new feathers.
Also according to BWP you can only safely age a 1st winter with pale tips to the retained coverts but am a bit confused as if all adults moult all feathers then surely a bird just showing two generations of feathers should be enough to age it??

Bird 1
This female has adult and juv greater coverts so presumably a first year. As I have been looking through these pics it seems that nearly all the first year birds consistently show around half new and half old greater coverts. A few chevrons on the lower belly/vent area on this one

Bird 2

Bird 3 First year male

Bird 4

Bird 5 Another female with 2 generations of greater coverts

Nice head pattern

Bird 6. First year male with lovely deep orange base to bill and eye ring

Bird 7 Classic first year male with new body feathers and old flight feathers. Quite well marked chevrons on this one. Eye ring a very pale yellow on this one and bill almost all grey

Bird 8 Not completely sure what is going on here! It appears to have 2 generations of greater coverts but close inspection reveals the inners to be rather worn and the outers looking in better condition. Also the pale areas at the tips are on the supposed replaced coverts so this along with the median coverts must just be pigment loss. It is certainly the most multi-coloured bird so far

A Song Thrush would be proud of those breast spots

Bird 9. Getting a bit out of my depth now. Looking at the greater coverts it looks as though they are all the same generation the pale one at the end looks like an alula feather? Also the inner feathers do look tattier than the outers which I suppose would be consistent if they were replaced first. It has also got 2 generations of tertials

Bird 10 Adult female? with same generation greater coverts although is that two generations of tail feathers?

Bird 11

Bird 12 Another first year male

Bird 13 presumed first year female with at least a couple of old outer greater coverts

Bird 14 another first year male, brighter billed than bird 12 with a less scraggy tail

Bird 15, the 5th first year male with some loss of pigment in tail and primaries

Bird 16, Very smoky looking bird

Bird 17

Bird 18. Bit of a racket tail going on