MATE GUARDING AND EXTRA-PAIR PATERNITY IN NORTHERN CARDINALS

We studied patterns of mate guarding and paternity in 21 pairs of Nort hern Cardinals (Cardinalis cardinalis) nesting in central Kentucky. DN A fingerprinting revealed that five of 37 nestlings (13.5%) resulted f rom extra-pair fertilizations (EPFs). Of 19 broods sampled, three (16% ) had at least one extra-pair young. Although our observations of male cardinals making extra-territorial movements suggest that some males in the population may actively pursue EPFs, the percentage of extra-pa ir young in our study was lower than reported for many other passerine s. Three non-exclusive factors may have contributed to this low percen tage. 1. Male cardinals may gain more from parental efforts than from pursuing extra-pair copulations (EPCs). 2. Females in resident species such as Northern Cardinals probably have more opportunities to assess the quality of prospective mates prior to pairing than do females in migratory species and so EPCs may be less likely to be beneficial to f emales. 3. Most male cardinals exhibited mate guarding behavior. Males maintained contact with fertile mates 72.8% of the time during initia l nesting attempts and, in addition, males followed females more often than females followed males in nine of 10 pairs.