New Study Highlights Dramatic Impact of Cats on Young Birds In Washington, D.C. Suburbs

This new study funded by the American Bird Conservancy and published in the Journal of Ornithology measured nest success and post-fledging survival.  While these measures varied significantly between urban sites, feral cats were seen as the #1 cause of nest and fledging failure.  Read on for more...

Understanding factors that limit the productivity and survival of birds in rapidly hanging human-dominated landscapes are key to managing future population persistence. To date, few studies have quantified both nest success and post-fledging survival for birds breeding withinthe suburban matrix. Here, we estimated nest success and juvenile post-fledging survival for Gray Catbirds (Dumatella carolinensis) and used those site-specific parameters to model source–sink dynamics at three sites in suburbanWashington DC (USA). Cumulative nest success probability varied substantially among suburban sites and indicated that in some cases suburban habitats may provide suitable breeding sites for passerine birds. In addition, we documented the effects of sex and brood size on post-fledging survival rates and determined the role of predation on dispersing fledglings. Like nest success, estimates ofpost-fledging juvenile survival also varied among sites andhighlight the importance of site-specific demographic estimates in urban habitats. Predation accounted for 79%of all mortalities, with 47% of known predation events attributable to domestic cats (Felis catus). Our models of source–sink dynamics underscore the importance of seasonal recruitment parameters for calculating population growth rate and subsequent persistence. This study provides parameter estimates for two critical life history stages in the avian annual cycle in the suburban matrix andposits that predation drives differential nest and post-fledging survival within human-dominated environments