Tuesday, February 20, 2007

Chaffinch (Fringilla Coelebs)

I am attempting to identify all the life in my garden. This posting marks a return to discussing my garden's bird life, specifically the chaffinch (Fringilla coelebs).

Photo 1 shows a hen chaffinch on a branch of my apple tree and photo 2 the more brightly coloured cock.

In an attempt to learn something about chaffinches I have been reading Finches, Ian Newton (publ. Collins New Naturalist 1972). Some of the things I've learned:

British chaffinches rarely move more than a few km from their birthplace. In winter however, numbers in Britain are greatly increased by an influx of migrants from Northern Europe; Indeed Latin coelebs meaning bachelor is due to Linneaus who observed that those chaffinches remaining to over-winter in his native Sweden were primarily male. Chaffinches visiting Britain typically arrive in October and depart in March. I wonder whether the birds in my photo are locals or foreign visitors?

In winter chaffinches flock, but in the breeding season (typically late April to early July) they are territorial (unlike goldfinches) with pairs occupying territories of around 1000-12000 sq.m. I've crudely estimated the area of my garden as a little over 500 sq.m., so it seems I can accommodate at most half a breeding pair. (I would say however that it's not uncommon for me to see up to half-a-dozen chaffinches in my garden at one time).

The chaffinch seems to be one of the less dexterous finches, and is unable to hold or manipulate seeds with its feet (unlike the goldfinch). Despite this it is one of Britain's most successful birds with 5.4million territories in Britain (according to my RSPB Handbook of British Birds, Holden and Cleeves 2006)

With a typical life expectancy of 2.5years it seems Chaffinches get a better deal than robins. That said however, their love life is no bed of roses! To quote Dr. Newton:

"Courtship in the chaffinch is characterised by tentative ambivalent behaviour involving conflicts between fear, aggression and sexual attraction"

Despite this, chaffinches mate for life.

Cock chaffinches begin looking for territory in February. I enjoyed the description of the young cock chaffinch hopping around trees in a prospective territory examining the forks between branches (the preferred nesting site for the female he hopes to attract) first with one eye, then the other.

Males attract females by song and will sing up to 3,300 times in 24hrs. (I thought this was a lot until I read that the the Red-eyed Vireo may sing an astonishing - and I imagine potentially monotonous, if you happen to have them in your garden! - 24,000 times in the same period).

When a cock and hen are finally ready to mate the cock does a

" 'pre-copulatory dance' , in which [he] patters to and fro before the hen with short steps"

I'm not certain, but I think I may just have caught this in photo 3.

In all, the chaffinch apparently has twenty-one songs. Chaffinch song is partly innate, but the young learn to add 'flourishes' to the basic song patterns. This means that not only are the voices of individual chaffinches distinct but that regional 'dialects' develop. I shall be listening out for the Oxfordshire accents of those in my garden.

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