Grasslands in the Midwest have seen a precipitous decline over the last 150 years, resulting in the loss of millions of acres of habitat for wildlife. A large majority of the land in the Midwest is privately owned and efforts to restore habitat on large scales will have to include partnerships with private landowners. Contour buffer strips of diverse native prairie in row crop fields have been demonstrated to be very effective at reducing nutrient and soil runoff and may also serve as quality habitat for birds on farms. However, narrow linear prairie strips could function as ecological traps, so investigation is warranted before prairie strips are adopted for wildlife habitat. We investigated bird use and nest success on 15 farms with contour strips planted to diverse native prairie in Iowa. Nests were located and monitored until success or failure and nest position, landscape, and vegetation variables were measured. Daily Survival Rate (DSR) was modeled for each species to determine the primary ecological factors influencing nest success or failure.
Results/Conclusions
From 2015-2017 we located and monitored 357 Red-winged Blackbird (Agelaius phoeniceus), 147 Dickcissel (Spiza americana), and 49 Vesper Sparrow (Pooecetes gramineus) nests. AIC model selection of daily nest survival rates showed nest age negatively influenced and vegetation density positively influenced nest survival for Red-winged Blackbirds. Dickcissel DSRs varied quadratically with nest age, with survival peaking around day 7, and farms with large, mature prairie strips had a positive influence on nest survival. Vesper Sparrow nests located in mature prairie strips had higher DSRs than nests found in other areas of farms. Habitat patch width and nest distance-to-edge were included in the model selection process, but did not competitively explain the variation observed in our data. These preliminary findings for three disparate passerine species indicate that despite their relatively fragmentation, contour strips of prairie provide improved on-farm nesting habitat in the agricultural Midwestern landscape.