Saturday, 23 April 2016

Bird of the week - Common crossbill

Here is a bird I had never seen until this morning, the (rarely seen) common crossbill.  The female is a beautiful metallic olive green and has an unmistakable bill.

The male is even more glorious, brightening up a cold gloomy morning.  Both birds were drinking from a muddy puddle but no less exciting to see for all that.  Many thanks to Phil and Denise for the tip off.

The common crossbill (Loxia curvirostra) is the only crossbill occurring in England; the Scottish and parrot crossbills are confined to Scotland (in the UK).  The last two have even deeper and stronger beaks.  These photos show the female's beak in more detail.  You can see her upper mandible curves to the right, whereas the male above has his upper mandible curving to the left.  Left-crossing and right-crossing morphs occur equally but the genetic basis for their occurrence has not yet been worked out.

The crossbill is a bird of conifer forests and it uses its bill to extract seeds from cones.  The maps show its distribution in the UK and in Europe.

Listen to Sir David Attenborough's BBC Radio 4 Tweet of the Day on the crossbill here.

1 comment:

  1. Terrific Chris, and thanks for the mention! Really great pics.