Predation on Northern Cardinal Nests: Does Choice of Nest Site Matter?

The fates of 121 nests of Northern Cardinals (Cardinalis cardinalis) in south-western Ohio were determined in 1991 and 1992. Success rate was only 15%, estimated by the Mayfield method. All failed nests were known or suspected to have been preyed upon. Several hypotheses to explain differences between the location of successful and failed nests were tested. None of those considered explained why the contents of particular nests were taken. We propose that a high incidence of predation by a rich guild of nest predators precludes the existence of predictably safe nest sites for cardinals. Instead, cardinals appear simply to be well-adapted to renest rapidly in response to the near randomness of nest predation. A similar adaptation may characterize many passerines.