Crooked beak mystery
28 January 2011
If you have a bird with a wonky beak turning up on your garden bird table you could help researchers looking into an unusual and unexplained phenomenon.
The British Trust for Ornithology (BTO) is asking gardeners to help them log incidences of deformed beaks for their Big Garden Beak Watch so they can gather more data and try to find out why it happens, which species are most affected, and how the birds cope.
Since the project started collecting reported sightings at the beginning of the month more than 100 beak abnormalities have already been logged, from crossed mandibles and elongated beaks to beaks bent to the side. About a third were blackbirds, with blue tits, robins, collared doves and starlings also showing peculiar beak shapes.
Most birds with deformed beaks adapt well, although some have to develop peculiar strategies to do so: one blackbird was seen drinking from drainpipes after its abnormal beak was not allowing it to drink in the usual way.
'Beak abnormalities have been reported in over 60 species of birds worldwide, from sparrows to pigeons, warblers to gulls,' said Dr Tim Harrison of the BTO's Garden Ecology Team. 'However there is much that we do not know and we hope that the public can help.'
Suggestions for possible causes of deformities in bird beaks include injury, nutritional deficiencies, exposure to environmental contaminants such as insecticides and herbicides, and disease, but none have yet been definitively proven to be behind the problem.