Effects of Recreational Trails on Northern Cardinals (Cardinalis cardinalis) in Forested Urban Parks

Though typically considered benign, recreational trails have the potential to both alter vegetation and disturb birds in ways that might in uence parental nest attendance rates and other behaviors that ultimately can affect reproductive success. We hypothesized that recreational trails negatively impact avian reproductive success either by (1) reducing nest attendance due to direct human disturbance or (2) modifying vegetation characteristics surrounding nests. From April to August of 2006 and 2007, 263 nests of Northern Cardinals (Cardinalis cardinalis) were monitored in 14 forested riparian sites containing paved and unpaved recreational trails in central Ohio. Vegetation characteristics were measured around 161 nests and 114 random locations. Trail use was estimated using cameras at seven of 14 sites. Nest attendance was not related to distance to trail, nest height, or trail use. We found little evidence that daily nest survival rates were related to distance to trail, nest attendance, trail use, or site. Rather, daily nest survival was best explained by and positively related to nest height. Though vegetation characteristics in randomly-located plots were unrelated to distance from trail, nests closer to trails were surrounded by more small stems (dbh < 8 cm), less native vegetation, and were placed at greater heights and farther from the foliage edge. Thus, birds may modify nest-site selection in relation to recreational trails.