Friday, January 7, 2011

Bullfinches

Soon after the waxwings moved on a party of bullfinches arrived on the crab apple tree in the garden, to feed on what was left of the shredded fruits, and they have been visiting frequently all day. The crab apples provide a useful diversion from our flowering cherry and pear blossom buds, which these birds tend to feed on from now until spring - although I'd have the bullfinches than the Concorde pears, which aren't very flavoursome. Generations of gardeners have lamented the ravages of bullfinches on their fruit trees. In his Journal entry of February 7th. 1791 Gilbert White, of Natural History of Selborne fame, wrote: "Bull-finches make sad havoc among the buds of my cherry, and apricot trees: they also destroy the buds of the goose-berries, and honey-suckles!" He also implicated greenfinches and, more improbably, grosbeaks in the devastation.

I have a suspicion that it's the seeds in the crab apples that the bullfinches are after, rather than the rotten fruits themselves, which are on the point of disintegration anyway.

As far as I can recall, we usually only have one family party of bullfinches in the garden in winter with just a single male, but over the last couple of days there have been four males in full, magnificent breeding plumage on the tree, which has generated some conflict.

Keeping wild bullfinches in cages has long been illegal but they were once popular cage birds and some bird fanciers learned that if they were fed exclusively on hemp seed their plumage would turn completely black. Birds can't make red or yellow carotenoid pigments, which come completely from their plant diet, either directly (from pear buds, in the case of bullfinches for example) or indirectly from eating animals that eat plants (from caterpillars in the case of blue tits), so it must be that hemp seed is low in these pigments and high in other darker ones that accumulate in the birds' feathers. But, as Gilbert White noted, all bullfinches are not equally susceptible. Here he is again, in his Journal entry for December 9th. 1781: "George Tanner's bullfinch, a cock bird of this year, began from its first moulting to look dingy; and is now quite black on the back, rump and all; and very dusky on the breast. This bird has lived chiefly on hemp-seed. But Dewey's and Horley's two bull-finches, both of the same age with the former, and also of the same sex, retain their natural colours, which are glossy and vivid, tho' they both have been supported by hemp seed. Hence the notion that hemp seed blackens bull-finches, does not hold good in all instances; or at least not in the first year."

If you are interested in reading more of Gilbert White's Journal entries, grouped together by year, they can be found by searching on the wonderful The Natural History of Selborne blog . Click here, for example, for his Journal entries for today, 7th. January between 1768 and 1793, which include mention of the first crossing from England to France by balloon, in 1785.

6 comments:

  1. Beautiful birds.... I MUST work on getting those berries in this coming spring, look at all the beauty I;m missing! However, I have been having a wonderful showing of Redpolls, Pine Siskins and male Cardinals - astonishing against the white snow and green hemlocks.

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  2. I remember a few years ago standing underneath a Wych Elm (Ulmus glabra) in Gibside and becoming aware of the occasional confetti-like samaras falling from the sky. On closer examination I noticed that they all had their centres missing; i.e. the seeds were gone. I looked up and in the canopy I saw bullfinches carefully nibbling the seeds directly from the centres of the samaras and discarding the rest.

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  3. Cardinals! Now I am jealous Valerianna! We have siskins and redpolls .... but cardinals must be wonderful to watch...

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  4. Interesting, Dougie. I've sometimes seen bullfinches eating dock seeds in autumn. I wonder if they switch from seeds to buds as the seed supply runs out towards the end of winter?

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