Tuesday, February 9, 2010

King Harrys

The Goldfinch rejoices in a number of old rural names including goldie, gold linnet, redcap and King Harry.

Errol knows a thing or two about Goldfinch. He lives in the south of England and he sees and catches plenty of them because it’s warmer down there than in the north west of England where I live. He probably also sees a lots more on migration than I do here in Lancashire because many Goldfinches migrate south in the autumn.

After my recent October 2009 retrapping of a Goldfinch that had been ringed down in sunny Surrey in January 2009 Errol told me about some of his own experiences with ringing Goldfinches in the last six or seven years where he lives in Bedfordshire.

Surrey to Lancashire 341 kms

Below I quote Errol’s work on the subject.

“During the last six or seven years, the number of Goldfinches using garden feeders has increased. This is partly due to the presence of Nyjer feeders but, more lately, the addition of sunflower hearts to the garden bird-table menu. As a consequence, numbers have also increased “in the field” throughout the year, allowing the species to be caught away from garden sites".

Goldfinch x Month 2007

"There is a distinct pattern to the numbers of birds caught in any month. The above graph shows quite clearly the better numbers caught from August to December, with a distinct peak in September and October. This coincides with the main passage movement southwards of the species, together with the presence of many young of the year. Garden feeders are an easy source of protein shortly after first-light, especially after a ‘cold’ night, and again in the afternoon if foraging for natural foods has not been very successful for the birds. A second noticeable feature of trapping Goldfinches is the variance between the sexes at different times of the year. An analysis of our data (for 2007) shows that males in the population seemingly outnumber the females by ~5:4. More importantly, the percentage of females caught during the year varies quite a lot. This may be an artefact of catching at feeding stations or differential feeding strategies between the sexes. However, it is more likely defined by the differential abmigration between the sexes (females moving further south in winter – possibly to Europe). Female numbers are at their lowest in January at less than 20%, as in the graph below".

% of Female Goldfinch

It is reasonably easy to distinguish male and female Goldfinch in the hand, less so in the field, but of course it is only by ringing them that individual males and females may be recognised. The page reproduced from “Svensonn” shows the differences.

Page 295, Identification Guide to European Passerines

Thanks for the gen Errol.

Read more from Errol and the local ringing group exploits at http://ivelringinggroup.blogspot.com/


NicoleB said...

That's one gorgeous bird!
Thanks for all the Info!

Unravel said...

This is something interesting for me!
As I am from a tropical country like Thailand, most of vagrants found in winter are usually female or juvenile birds. We got our first female Black Redstart about 10 years ago and the first female Long-tailed Duck 3 years ago, I think there are more but I can't name the others now. Maybe it is not only for the case of goldfinch.

Unravel said...

Oh I just saw your comment in my gallery in Pbase.
Thanks a lot! Someone also gave me a book of Tunnicliffe's sketches long time ago too. He's such an inspiration.

Forest the Bear said...

Great pics as always Phil...lots of good info there too. Going over now to read more from Errol and the group.

dAwN said...

Wow..Gorgeous Bird...great information..

NicoleB said...

It's amazing to learn more about nature every day :)

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