Thursday 29 November 2018

Bullfinches eating Guelder rose berries

A group of Bullfinches were feeding just outside Dalby Forest visitor centre this afternoon. We watched them from a window, just over them, and they seemed quite unaware of us, providing a great opportunity to watch this usually shy bird in action.
 Bullfinches are seed predators of many fruit trees. Blackbirds, Thrushes and Woodpigeons are seed dispersers, they eat the berry whole, digest the pulp and the seeds drop to the ground, undigested and prepared to germinate. This is the reason trees and bush species evolved fruits, as the way to disperse their seeds. In contrast, seed predators discard the flesh and eat the seeds inside each fruit. Many finches, like Hawfinches, Greenfinches and Goldfinches, are seed predators too.
Bullfinches favourite seeds include Honeysuckle, Rowan, Elder, Whitebeam and Blackberries, each ripening at different times of the year. Today, they were feeding on the bright red berries of the Guelder Rose, a late fruiting small tree. In their fantastic book "Birds and Berries", Barbara and David Snow document how bullfinches are one of the main seed predators of Guelder Rose.
 The bullfinches stretched to reach the berries (top shot) and used two techniques to get at the seed. They either opened up the fruit and picked the seed, leaving the flesh hanging from the bush or picked the berry and deftly extracted the seed. They will even hovering in front of the bunches of fruits to reach the most difficult ones.
A male picks a berry.
Female extracting a seed...
...and dropping the flesh.
There were not only bullfinches at the tree, a lone Robin, a seed disperser, was feeding on the berries, so even though there was a lot of seed predation going on, it's likely the Guelder Roses will manage to get some of their seed seeds to germinate.

More information
Snow, B. and D Snow 1988. Birds and Berries. T & AD Poyser. 268 pp.

3 comments:

  1. Lovely pictures. I read that the reason Little Owls were brought to England in the 19th century was in the hope that they would prey on the Bullfinches that were eating fruit farmers' crops. (Until then Little Owls were rare, though they are mentioned in Bewick's British Birds of 1798 as being present in Yorkshire, Flintshire and the London area.)

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  2. Thank you Ralph. I never knew that, I wish we had Little Owls in our local park, but I guess the park is too small and the trees not as old as the London ones. They are common enough in the outskirts of Hull.

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  3. Hi Africa, I just used the photo at the top to illustrate newsletter to farmers asking them to leave some hedges uncut as some species flower and fruit on second year wood (like guelder rose)
    Thanks
    Jemma

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