Nest Survival of Grassland Birds in Warm- and Cool-season Grassland Restorations

Abstract

Grassland restorations are being conducted, in part, to restore habitat for declining grassland bird populations. These restorations commonly utilize both native warm-season grasses and exotic cool-season grasses in seeding mixes. While variation in community assemblage and abundance of grassland birds between these habitat types has been studied, knowledge of patterns in nest survival among warm- and cool-season grassland restorations is incomplete. We examined patterns in nest survival of grassland birds between restored warm- and cool-season grasslands in west-central Missouri. We found 35 Henslow's Sparrow (Ammodramus henslowii), 40 Dickcissel (Spiza americana), and 20 Eastern Meadowlark (Sturnella magna) nests from 2010 to 2011. Using the logistic exposure method, we estimated that the Henslow's Sparrow had high daily survival rates (0.977) across the nest period (first egg to fledging), while estimates of Dickcissell (0.947) and Eastern Meadowlark (0.961) daily nest survival were similar to previously recorded estimates. Grassland habitat type was an uninformative parameter in models of daily nest survival rates for all study species and in models of brood parasitism by Brown-headed Cowbirds (Molthrus ater) on Dickcissell nests (18% of all nests parasitized). Our findings suggest that warm- and cool-season grasslands might similarly satisfy breeding requirements for these grassland bird species.