Identifying predators clarifies predictors of nest success in a temperate passerine

Abstract

Summary1. Nest predation negatively affects most avian populations. Studies of nest predation usually group all nest failures when attempting to determine temporal and parental activities, habitat or landscape predictors of success. Often these studies find few significant predictors and interpret patterns as essentially random. 2. Relatively little is known about the importance of individual predator species or groups on observed patterns of nest success, and how the ecology of these predators may influence patterns of success and failure. 3. In 2006 and 2007, time-lapse, infrared video systems were deployed at nests of Swainson's warblers (Limnothlypis swainsonii Audubon) in east-central Arkansas to identify dominant nest predators and determine whether factors predicting predation differed among these predators. 4. Analysis of pooled data yielded few predictors of predation risk, whereas separate analyses for the three major predator groups revealed clear, but often conflicting, patterns. 5. Predation by ratsnakes (Elaphe obsoleta) and raptors was more common during the nestling period, whereas predation by brown-headed cowbirds (Molothrus ater) occurred more during incubation. Additionally, the risk of predation by raptors and cowbirds decreased throughout the breeding season, whereas ratsnake predation risk increased. 6. Contrary to expectations, predation by ratsnakes and cowbirds was more common far from edges, whereas raptor predation was more common close to agricultural edges. 7. Collectively, our results suggest that associating specific predators with the nests they prey on is necessary to understand underlying mechanisms.

Role of topography, canopy structure, and floristics in nest-site selection and nesting success of canopy songbirds

“…, snakes are more likely to depredate nests during the nestling phase(Benson et al, 2010;Stake et al, 2005), an association we found for Cerulean Warblers.Fig. 5.…”

Habitat fragmentation reduces nest survival in an Afrotropical bird community in a biodiversity hotspot

“…Alternatively, landscape structure and nest location may mediate predation risk through alteration of predator searching behavior and/or the influence of habitat structure in impeding predator searches (24,30). Indeed, there is supporting evidence from temperate regions that predation pressure can vary among major nest predator types as a function of area (30,31) and distance to edge (31)(32)(33). There is also evidence from temperate regions that habitat structure of nest sites can mediate predation risk via changes in predator searching behavior (29).…”

Shifts in Dominant Nest Predators along a Rural-to-Urban Landscape Gradient

“…, Benson et al 2010, Bolton et al 2007, Brown et al 1998, Buler and Hamilton 2000, Carter et al 2007, Coates et al 2010, Conner et al 2010, Farnsworth and Simons 2000, Franca et al 2009, Franzreb 2007, Granfors et al 2001, Grant et al 2006, Herranz et al 2002, King and DeGraaf 2006, Liebezeit and George 2003, Lusk et al 2006, Major and Gowing 1994. Marzluff et al 2007, McKinnon and Bety 2009, Moore and Reid 2009, Morgan et al 2006, Morrison and Bolger 2002, Perkins et al 2005, Peterson et al 2004, Pietz and Granfors 2000.…”