The house finch (Carpodacus mexicanus) has joined the short list of birds that can smell, apparently using this sense to detect predators.
Timothy Roth and his colleagues at Indiana State University in Terre Haute placed 51 wild finches in enclosures in which food sat in ventilation gaps. For two days, unscented air streamed through these gaps and the finches happily moved into the airflow to eat. Roth and his team then gently blew air over cat faeces, rabbit faeces or water before wafting it into the enclosures.
Both faecal odours reduced the amount of time the finches spent at feeders. The effect was strongest for cat scent, suggesting that finches can tell a predator from its poo.