Monday, 24 February 2014

Black Park - 19 February 2014

Another day where getting out was possible, and with lower wind speed predicted it was decided to give the open area of Black Park, our usual site in the park a try, so I met up with GDB who came down from Bicester to give it a try for Redpoll and Redwing. Whilst in the process of setting up four Crossbills flew over and a flock of 30 odd Chaffinches put in an appearance but soon moved on. Another flock of 50 odd were found in an area of Beech mast as we left the park. No Redwings put in an appearance but we had a slow trickle of Redpolls and a single Goldcrest, but nothing else.

We caught one Common Redpoll with a Stravanger, Norway ring, which was pale and had a 79 wing, a considerable range beyond Lesser Redpoll wing length (max 75), but only weighed 12.1, plus another, female with a wing of 73, which is within Lesser range and only a weight of 11.9. We have caught other Common Redpolls this winter where the birds felt bulkier and weighed 13-14g.

The problem with Redpolls - as you go through the various regions they are found in - colours vary, in even within the two groups Lesser and Common groups, some more obviously than others, sizes vary, as do weights - within what has been termed the Common/Mealy group, a Scando bird, or one from Iceland or Greenland, will all show variations in birds from these three areas, and is the variation between these various clines sufficient that they are true species or just ssp? And, where Commons meet Lessers are they distinctly separate that there is no regular interbreeding? This is not an issue in Greenland or Iceland as there are no local breeding Lessers, but as we know isolation might be the only interbreeding inhibitor. But, even if they are lumped, we can still do the Lesser/common ssp bit - as we do with the various races of Chiff - just so we can still argue over what ssp it is, rather than the species.

 5 male Common Redpoll rung at Stravanger, Norway
79 wing weight 12.1

5 female Common Redpoll with 5 male
Lesser Redpoll, wing 73 weight 11.9

Total: 11 (1)

Goldcrest - 1
Lesser Redpoll - 9
Common Redpoll - 1 (1)