Conservation Conversations 19

What is 'Killing' Cock Robin?

It has been reported (http://environment.guardian.co.uk/conservation/story/0,,2064930,00.html) by Dr Richard Fuller in Biology Letters that European robins in Sheffield are singing at night in areas of Sheffield where traffic noise in particularly loud (the phenomenon is much more linked to decibel level than to lighting). The singing is, of course, designed to attract mates and to deter rivals. It seems that the robins are adjusting their time of singing to increase the effectiveness of their 'messages' (their songs are only slightly higher pitched than traffic noise). This (along with other observations on a variety of bird species) confirms that urbanisation may have subtle effects on the behaviours of such animals. There is, naturally, some debate about whether their long periods of activity (rather than singing in the day and sleeping at night) places additional pressures on birds that show this behavioural adaptation. Game theory suggests, of course, that the benefits of singing at night must outweigh the costs of doing so. It would be very interesting to compare the number of chicks successfully reared by robins in locations with and without high levels of traffic noise.