Date of Graduation

8-2019

Document Type

Thesis

Degree Name

Master of Science in Biology (MS)

Degree Level

Graduate

Department

Biological Sciences

Advisor/Mentor

Willson, John D.

Committee Member

Siepielski, Adam M.

Second Committee Member

Westerman, Erica L.

Keywords

bird; grassland; migration; nest; restoration; wildlife conservation; winter

Abstract

Dwindling populations of North American grassland birds are linked to habitat loss. Tallgrass prairie only covers 3% of its pre-settlement-era range. Small-scale restoration projects attempt to increase acreage for prairie avifauna, and while some breeding grassland species are present at these sites, nesting success and non-breeding use are still largely unknown. Both life history aspects are required for effective grassland bird conservation. My first objective was to access nest success of the Dickcissel (Spiza americana) at two remnant and two restored tallgrass prairies in Northwest Arkansas. From May-August 2017 and 2018, I found 114 nests that I monitored to determine ultimate fate. I selected vegetative characteristics collected at nest and random sites combined with site-level variables to inform a logistic exposure model. Mean nest success was 8.5%, which varied by site but appeared unaffected by restoration status. Excluding predator presence, the most important predictors of nest success were site size size and brood parasitism. Prairie Kingsnake (Lampropeltis calligaster) was the primary nest predator. My second objective was to identify field site characteristics and vegetation use by non-breeding grassland-obligate birds in two remnant and three restored tallgrass prairies in Northwest Arkansas. Between September 2017 and May 2018, I tallied 44 species. Only eight species were grassland-obligate, but this assemblage accounted for about half of all detections. Grassland-obligate diversity was similar across seasons and between sites, except for a small isolated restored prairie which hosted much lower diversity. Dickcissel and Sedge Wren (Cistothorus platensis) detection rates increased significantly with distance to woody edge, indicating area sensitivity. Some species used primarily grass and forb, others utilized burned areas, and Le Conte’s Sparrow (Ammodramus lecontei) frequented shrubs. Northwest Arkansas’ remnant and restored tallgrass prairies are valuable for nesting Dickcissel and a suite of non-breeding grassland birds. Special consideration for maintaining large parcels with fire that are distant from paved roads should be given for breeding Dickcissel. Acquiring large parcels and maintaining a shifting vegetation mosaic while retaining some woody vegetation could satisfy diverse habitat preferences for non-breeding grassland avifauna.

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