Birds of Indian Subcontinent

Conservation Reserve Program: Source or Sink Habitat for Grassland Birds in Missouri?

Publication Type:Journal Article
Year of Publication:1999
Authors:McCoy, TD, Ryan, MR, Kurzejeski, EW, Burger, Jr., LW
Journal:The Journal of Wildlife Management
Date Published:1999
ISBN Number:0022541X
Keywords:Agelaius, Agelaius phoeniceus, Ammodramus, Ammodramus savannarum, Cardinalidae, Carduelis, Carduelis carduelis, Carduelis tristis, Emberizidae, Fringillidae, Geothlypis, Geothlypis trichas, Icteridae, Parulidae, Spinus, Spinus tristis, Spiza, Spiza americana, Spizella, Spizella pusilla, Sturnella, Sturnella magna, Turdidae, Turdus, Turdus iliacus, Turdus maximus, Turdus merula
Abstract:The Conservation Reserve Program (CRP) has been credited with contributing substantially to the conservation of grassland birds. Although many species have nested in grasslands established under the CRP, little evidence of positive effect on populations has been reported. We measured reproductive rates and estimated fecundity of 7 grassland bird species in CRP fields in northern Missouri and compared those rates to estimates of fecundity needed to maintain stable populations (λ = 1). Under conservative assumptions of survival, CRP fields seemingly were source habitats (fecundity exceeded levels necessary for λ = 1) for grass-hopper sparrows (Ammodramus savannarum) and field sparrows (Spizella pusilla) in at least 2 of 3 years (1993: P = 0.02; 1995: P < 0.001) and pooled over 3 years (Ps < 0.001). Although evidence was less compelling, CRP fields were likely source habitat for eastern meadowlarks (Sturnella magna) and American goldfinches (Carduelis tristis). For American goldfinches, fecundity was greater than that necessary for λ = 1 in 1995 (P < 0.001), and pooled over 3 years (P < 0.001). Our pooled estimate of fecundity was greater than necessary for λ = 1 for eastern meadowlarks (Ps < 0.001), but only under a liberal assumption of survival in 2 of 3 years (1993: P = 0.001; 1995: P = 0.088). Fecundity of common yellowthroats (Geothlypis trichas) varied substantially; therefore, source-sink status alternated among years, although the pooled estimate of fecundity was less than required for λ = 1 (P < 0.001). Dickcissel (Spiza americana) fecundity was consistently less than necessary for λ = 1 (conservative survival assumption: all Ps < 0.001; liberal survival assumption: 1994 P = 0.008, pooled P = 0.014). For red-winged blackbirds (Agelaius phoeniceus), CRP fields were consistently a sink habitat (all Ps < 0.001). Based on our evidence, the CRP likely has contributed to the conservation of grasshopper sparrows, field sparrows, and eastern meadowlarks. Although large numbers of dickcissels and red-winged black-birds nested in CRP fields, there is little evidence that the CRP has contributed to populations of those species.
Short Title:The Journal of Wildlife Management
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith