WHEN PIGEONS HOME ALONE - DOES FLOCKING HAVE A NAVIGATIONAL FUNCTION

Using the flocking tendencies of homing pigeons (Columba livia) in fli ght, a first attempt was made to lest directly the hypothesis that gro up movement may have a navigational function. We manipulated the poten tial advantage of transfer of navigational information by releasing pa irs of homing pigeons in which none, one or both of the birds had prev iously been released at sites about 25 km from the home loft (while ov erall flying experience was standardized). Contrary to our prediction, locally naive birds did not follow experienced birds home, whereas ex perienced birds, with less navigational need to flock, were generally still paired on arrival home. Pairs in which both birds were locally n aive also tended not to home together. Under the conditions of our exp eriment, the tendency to fly together appealed not to have a navigatio nal function. However, and contrary to recent conclusions in the liter ature, our results do suggest that the initial flight behaviour of bir ds at novel release sites may constitute a navigational information ga thering strategy that is sufficiently important to over-ride gregariou s tendencies when the two conflict.