University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln The Prairie Naturalist Great Plains Natural Science Society 12-2017 Avian Diversity, Abundance, and Nest Success among Managed Prairies and Agricultural Plots in Oklahoma and Texas Phillip J. Leonard Douglas R. Wood Wayne E. Meyer Follow this and additional works at: https://digitalcommons.unl.edu/tpn Part of the Biodiversity Commons, Botany Commons, Ecology and Evolutionary Biology Commons, Natural Resources and Conservation Commons, Systems Biology Commons, and the Weed Science Commons This Article is brought to you for free and open access by the Great Plains Natural Science Society at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in The Prairie Naturalist by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 48 The Prairie Naturalist • 49(2): December 2017 Avian Diversity, Abundance, and Nest Success among Managed Prairies and Agricultural Plots in Oklahoma and Texas PHILLIP J. LEONARD, DOUGLAS R. WOOD, and WAYNE E. MEYER Department of Biological Sciences, Southeastern Oklahoma State University, Durant, OK, USA 74701 (PJL, DRW) Biology Department, Austin College, Sherman, TX, USA 75090 (WEM) ABSTRACT Over the last 50 years, grassland birds experienced rapid declines due to habitat loss and degradation as a result of agricultural practices. Our objective was to document the diversity, abundance, and nest success of bird communities using managed prairie and agricultural plots at the Tishomingo National Wildlife Refuge (NWR) in southern Oklahoma and Hagerman NWR in northern Texas. From April 1 to July 15, 2013–2014, point count surveys, nest searches, nest monitoring, and vegetation sampling were conducted among three habitat treatments: managed prairie, unharvested wheat, and fallow agricultural plots. Species richness values for potential nesting species were higher in managed prairies at both refuges, whereas species abundance rates varied among treatments. Nest success rates were low at both refuges due to nest abandonment and predators. Due to vegetation diversity, species were more likely to nest in managed prairies compared to agricultural plots with more homogenous vegetation at both refuges. Managed prairies at both refuges were relatively small and fragmented resulting in edge effects, such as increased nest predation and brood parasitism. We recommend increasing the area of managed prairies to provide more habitat for bird species at both refuges. KEY WORDS Agriculture, grassland birds, nest success, Oklahoma, prairie, Texas. Since the 1960s, the North American Breeding Bird agricultural plots on grassland bird species’ abundance, Survey (hereafter BBS) has quantified the population trends diversity, density, and nest success (Winter et al. 2006, Ribic of grassland bird species and found them to be declining et al. 2009b). This management strategy is employed by the more rapidly than any other bird community in North USFWS to a complex of refuges in the Midwest region. Due to America (Robbins et al. 1986, Johnson and Igl 2001, Vickery management paradigm shifts and funding, National Wildlife and Herkert 2001, Ribic et al. 2009a, Sauer et al. 2014). Refuges are exploring converting agricultural plots to native Breeding bird survey trend data for Oklahoma show that prairie plots in order to meet new management objectives. species such as field sparrow (Spizella pusilla) and dickcissel Our primary objectives were to 1) document the diversity, (Spiza americana) have experienced declines in breeding relative abundance, and density of bird communities using populations (–2.52 %/year, and –0.14 %/year, respectively) managed prairie, unharvested wheat, and fallow agricultural since 1966 (Sauer et al. 2014). Currently, only 4% of the plots at the Tishomingo National Wildlife Refuge (hereafter historical 68 million ha of prairie remain (Steinauer and Tishomingo NWR) in southern Oklahoma and the Hagerman Collins 1996, Herkert et al. 2003). The primary causes of National Wildlife Refuge (hereafter Hagerman NWR) in these declines were the loss and degradation of grassland northern Texas, 2) determine avian nest success among habitats, specifically, agroconversion of native prairies treatments, and 3) use a conservation index score to rank the (Askins et al. 2007, Noss et al. 1995, Vickery and Herkert value of each treatment type for grassland bird species. 2001). As a result of agroconversion, grassland birds were forced to use agricultural plots as an alternative to historical STUDY AREA prairies. Agricultural fragmentation reduces both the occurrence and density of breeding birds in small habitat The 6,663 ha Tishomingo NWR was located in southern fragments leading to sink populations (Herkert 1994, Vickery Oklahoma (14S 717068 E, 3786016 N) and provided a diverse et al. 1994, Winter and Faaborg 1999, Herkert et al. 2003). landscape for wildlife species including managed prairies and Habitat fragmentation also exposes birds to increased nest agricultural fields (Diggs and Wood 2010). Agricultural plots predation and brown-headed cowbird (Molothrus ater) brood were established to provide forage for wintering waterfowl, parasitism. Birds nesting in agricultural plots are subject whereas managed prairies were intended to provide nesting to anthropogenic disturbances such as pesticides and crop habitat for resident and migrant grassland bird species (U.S. harvest (Nocera et al. 2011). Fish and Wildlife Service 2010). Hagerman NWR in northern The U. S. Fish and Wildlife Service (hereafter USFWS) Texas (14S 708300 E, 3735651 N) was a 4,856-ha refuge solicited regional field research to determine the impacts managed similarly to Tishomingo NWR. Although habitat of site-specific management of prairie restoration and management schemes were similar, Hagerman NWRs Leonard et al • Avian Abundance in Managed Prairies 49 agricultural plots were structurally and compositionally 11.3, 17.5, 20.6 ha respectively), whereas fallow plots totaled different than agricultural plots at Tishomingo NWR. Seven 145.7 ha (6.1, 6.5, 10.7, 11.4, 25.5, 85.5 ha respectively). loam or sandy soil types occurred within the research plots Unharvested wheat fields consisted of winter wheat (Triticum selected at both refuges (Natural Resources Conservation aestivum), arrowleaf clover (Trifolium vesiculosum), hairy Service 2014). We selected nine research plots at each refuge. vetch (Vicia villosa), and common sunflower (Helianthus Three habitat management types: managed prairies, fallow annua), whereas fallow fields consisted of a variety of row plots, and unharvested wheat plots were assigned to three crops, grasses, and herbaceous vegetation (Leonard 2015). plots each. Managed prairies totaled 83.4 ha (10, 10, 12, 12.5, 18.7, 20.2 At Tishomingo NWR, we selected three agricultural fields ha respectively). Vegetation in managed prairies included that were divided into two halves with half assigned to the Kaw big bluestem (Andropogon gerardii), Cimarron little Leonardunharvested et al. • Avian wheat Abundance treatment and in the Managed other half Prairies assigned to the bluestem (Schizachyrium scoparium), Cheyenne indiangrass20 fallow treatment. At Hagerman NWR, 3 plots were selected (Sorghastrum nutans), Blackwell switchgrass (Panicum that had fallow (unplanted for 2–6 yr) or unharvested wheat virgatum), El Reno sideoats grama (Bouteloua curtipendula), patches. Unharvested wheat plots totaled 69.9 ha (6.5, 6.5, 7.5, Texoka buffalo grass (Buchloe dactyloides), and Sabine 435 Table 1. Mean number of detections per point (± SD) of bird species among treatment plots at Tishomingo and Hagerman Table 1. Mean number of detections per point (± SD) of bird species among treatment plots at Tishomingo and Hagerman NWRs, 436 2013–2014.NWRs, 2013–2014. Managed Managed Unharvested Unharvested Prairie Prairie Fallow Fallow Wheat Wheat Species (Tishomingo) (Hagerman) (Tishomingo) (Hagerman) (Tishomingo) (Hagerman) Wild Turkey - 0.05 (0.19) 0.02 (0.08) - - - Killdeer 0.03 (0.04) - 0.01 (0.03) - - 0.01 (0.03) Mourning Dove 0.13 (0.12) 0.20 (0.18) 0.18 (0.17) 0.12 (0.13) 0.20 (0.23) 0.12 (0.13) Yellow-billed Cuckoo 0.02 (0.04) 0.01 (0.02) 0.01 (0.03) - 0.02 (0.04) - Ruby-throated Hummingbird 0.03 (0.03) 0.03 (0.04) 0.05 (0.07) 0.01 (0.04) 0.13 (0.08) - Western Kingbird 0.01 (0.02) 0.03 (0.01) 0.01 (0.02) 0.01 (0.02) 0.03 (0.07) 0.01 (0.02) Eastern Kingbird 0.01 (0.02) 0.01 (0.05) 0.09 (0.15) - 0.03 (0.06) 0.01 (0.02) Scissor-tailed Flycatcher 0.04 (0.05) 0.05 (0.08) 0.14 (0.20) 0.06 (0.08) 0.09 (0.20) 0.08 (0.11) White-eyed Vireo 0.01 (0.02) - - - - - Bell's Vireo 0.03 (0.09) - - - - - Carolina Wren - 0.004 (0.01) 0.01 (0.03) - - - Bewick’s Wren - 0.01 (0.02) - - - - Blue-gray Gnatcatcher 0.17 (0.19) 0.15 (0.18) 0.002 (0.01) 0.01 (0.02) - 0.01 (0.04) Eastern Bluebird 0.05 (0.03) 0.11 (0.17) 0.03 (0.09) 0.47 (0.38) 0.24 (0.57) 0.14 (0.16) Gray Catbird 0.01 (0.02) - - - - - Northern Mockingbird 0.03 (0.05) 0.02 (0.05) 0.01 (0.03) - - - Brown Thrasher 0.01 (0.02) - 0.002 (0.01) - 0.01 (0.02) - Common Yellowthroat 0.01 (0.02) - 0.01 (0.03) - 0.02 (0.04) - Yellow-breasted Chat 0.06 (0.09) - - - - - Field Sparrow 0.01 (0.02) 0.004 (0.01) 0.01 (0.03) - - - Leonard et al. • Avian Abundance in Managed Prairies 0.004 21 Lark Sparrow 0.01 (0.02) 0.004 (0.01) 0.02 (0.05) 0.01 (0.02) - (0.01) Grasshopper Sparrow 0.02 (0.05) 0.01 (0.02) 0.03 (0.05) 0.13 (0.16) 0.02 (0.04) 0.01 (0.02) Northern Cardinal 0.22 (0.18) 0.29 (0.23) 0.02 (0.04)