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It is widely accepted that birds respond best to distress calls given by their own species. There is little information available however, which evaluates the effect of inter and intraspecific distress calls. During 1997 and 1998, distress calls from sub populations which are unfamiliar to local birds of the same species were assessed in Hong Kong and the U.K. Results were examined on a taxonomic basis. Response was found to be greater when con-specific calls were used. Response rates declined further as taxonomic relatedness decreased. Unlike other studies, distress calls of UK birds were effective on the same species in Hong Kong, suggesting that dialect may be less important than previously thought.