Behaviour and condition
Despite the often gross nature of beak abnormalities, most Big Garden Beak Watch participants thought that affected individuals were in good condition and behaved much like normal-billed birds. Indeed, many deformed birds have been popular companions for armchair birdwatchers for weeks, if not months or even years! Naturally, deformed birds often make adjustments to feed - tilting their head to one side to feed from the ground has been a frequently observed behavioural adaptation to an overgrown bill, for example - but, generally, deformed-billed birds have found food and water, and mixed well with other birds.
Preening can be difficult with a wonky beak and around one in six individuals were judged to have plumage that was in poorer condition than a normal-billed bird of the same species. However, only 5% of Big Garden Beak Watch participants thought that the deformed bird that they saw had any signs of disease (e.g. fluffed up feathers, lethargic). Of those birds that were seen during the spring and summer, 13% were confirmed to be breeding. Of these, nearly three in five seemed to do so successfully (e.g. seen bringing food to young). Nearly one in ten, however, appeared to be unsuccessful. The rest were uncertain. This is perhaps understandable given the high frequency at which specific foods must be found and provided efficiently to young or to a mate during reproduction.
A number of fascinating behavioural accounts have emerged through the on-going survey. In Cheshire, Carol and Joy Mitchell-Lisle saw a Wood Pigeon with a crossed bill try more than 20 times to pick up a peanut in the snow before eventually being successful, and it stayed feeding in the garden after dark. Meanwhile, in South Yorkshire, Sheila Hill observed a deformed Jackdaw being fed by another as November neared its end. In Glasgow, Thomas Daniels noted that a deformed Carrion Crow spent more time investigating possible food sources than other crows, knocking over plastic plant pots and flying up and dropping them like shells on a beach.
Many deformed birds are unusually tame around humans, probably as a result of an increased reliance on bird foods provided by householders. A pheasant with a crossed beak in Northumberland, for example, was tame enough to eat from the hand of survey participant Christopher Alborough, while a Blue Tit with an elongated beak in Berkshire was bold enough to follow Gillian Lucraft into her kitchen!
Have you ever seen a bird with a deformed beak in your garden? How was it behaving? Please let us know through Big Garden Beak Watch!
Working together for seabirds
BTO work supports effective monitoring of our seabirds and aims to provide opportunities for a new generation of seabird surveyors.
Bird ID basics (3 modules, Wednesdays 10am)
The training involves three weekly online modules, with a large interactive component and complemented by supported self-study exercises. We place a strong emphasis on providing you with tools and techniques that will...