Influence of habitat patch characteristics on the success of upland duck nests

When there is a rich guild of nest predators that use different modalities and techniques to locate hidden nests, we hypothesized that no habitat patch characteristic will consistently predict nest success, because if such a characteristic existed then predators would develop a search image based on it and use that characteristic to increase their hunting efficiency for nests. We tested this prediction in the Prairie Pothole region of North Dakota by characterizing the features of 16 habitat patches that contained >1,800 dabbling duck nests. Nest success was monitored during both the early and late nesting season over 2 years. Nest success was generally low and highly variable among habitat patches and across seasons and years. We found that nest success was rarely correlated with patch size, nest density, predator abundance and richness, abundance of alternative prey for predators, and visual and physical obstruction provided by the vegetation. Those few habitat patch characteristics that were correlated with nest success during a particular single year or season were not correlated during other seasons or years. Hence, our results supported the hypothesis that no habitat patch characteristic can consistently predict, nest success.