Two of the Redpolls were juvenile males (Euring 5) in their second calendar year and had retained juvenile greater coverts.
Note the contrast between the inner adult type greater coverts and the outer juvenile ones retained after the birds post juvenile moult last year. Some times its easier to see this contrast on the closed wing as on the bird below.
Having studied Biology at University evolution has always fascinated me and I can recall reading Charles Darwin's 'Theory of Evolution' and how he postulated his theories after studying the finches on the Galapagos Islands. The head shots of the finches above show they all have the same type of seed-eating bill but are totally different to look at. Each is specialised in its own way and utililise different food resources in the wild. In my garden though they all go straight for the sunflower hearts.
Hopefully it'll be a big Siskin year and I'll catch a few more. I've only caught Siskins in one previous year since 2011 - 2013 when I caught a total of 20 birds.
2 comments :
We've had lots of Siskins over the last few weeks, but sadly no Redpolls. We've previously only had both species passing through. Is it true that Siskins move in to gardens during prolonged periods of rainy weather?
Anthony.
I wouldn't say that's necessarily true but in common with other 'garden' birds Siskins will tend to utilise garden supplies when their natural food is in short supply or prolonged bad weather makes it harder for them to find their natural food. Siskins are irruptive and some years we have good numbers and in others virtually nothing.
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