Do dirty birds last longer?
Most birds like to bathe when they can; it keeps their feathers in prime condition and there's every indication they also simply enjoy a splash.
But does being dirty make them better survivors?
A recent study in the UK, published today in the Royal Society's journal Biology Letters, found that captive European starlings who didn't have the opportunity to bathe were not only more wary and nervous, they were also more likely to crash into objects when flying away from percieved danger.
Researchers at the Centre for Behaviour and Evolution at Newcastle University prevented one group of 20 starlings from bathing for three days, then played a recorded alarm call. Another group were allowed to bath regularly before also being exposed to the alarm call.
The dirty birds were slower to begin eating after hearing the recorded call and were visibly more nervous feeders than the clean birds. The scientists hypothesised that the stained starlings ability to fly was compromised by their dirty feathers which made them more nervous and edgy and quicker to flee a percieved threat; they also suggested that birds with no access to bathing water considered escaping from potential threat to be more important than avoiding physical harm from collisions.Cleaner birds were less likely to respond to the threat call while they were bathing leading the researchers to wonder if cleaner birds were better able to judge the level of danger signalled by the call.
The researchers hypothesized that lack of access to water for bathing could lead to chronic stress or anxiety like symptoms in captive starlings.