Do natural areas in urban landscapes support successful reproduction by a group of conservation priority birds?

Abstract

AbstractIf conservation priority birds are to persist in an increasingly anthropogenically altered world, suitable habitat must be created or preserved in potentially unsuitable landscapes. While natural areas in urban environments may provide habitat for declining groups of birds, little is known about effects of urbanization on the reproductive success of birds, such as grassland birds, that are typically thought to be associated with more rural landscapes. While typical conservation efforts have focused on conserving large patches of grassland in landscapes containing minimal amounts of woody vegetation and development, the assumption that habitat located in developed landscapes is of poor quality has not been tested and may wrongly devalue grasslands located in an urban matrix. To examine the influence of development on habitat quality for grassland birds, we studied grassland bird nest predation and brood parasitism in patches of varying size along an urbanization gradient in northeastern Illinois. Because nest predation is the primary cause of reproductive failure and a potentially limiting factor for grassland bird populations, we used miniature video cameras to identify predators at a subset of nests. From 2012 to 2013, we monitored 432 nests of 16 grassland bird species. Nest predation rates decreased with urbanization in the landscape as did probability of brood parasitism. We filmed 44 nests and documented 19 predation events. We found that coyotes Canis latrans, white‐tailed deer Odocoileus virginianus and thirteen‐lined ground squirrels Ictidomys tridecemlineatus were important nest predators in our study system. Contrary to prior assumptions, our results suggest that grasslands located in urban landscapes may provide habitat of equal or greater quality than many rural grasslands.