Status and Conservation of the Bobolink (Dolichonyx oryzivorus) in Argentina

It is clear that grassland bird populations have declined significantly during the last 30 years. Declines are widespread in North America, making grassland birds a continental conservation priority. In New England and New York steep population declines for many species warranted listing in many states. Habitat loss through farm abandonment and the subsequent succession of grassland habitat to forest is the principle cause of the observed population declines. Because of the concern for grassland bird conservation and the lack of an understanding of the regional distribution and relative abundance of grassland birds in New England and New York, we coordinated a survey of breeding grassland birds throughout this region from 1997-2000. We estimated the occurrence and relative abundance of seven obligate grassland bird species at 1,140 sites. Sites included hayfields, fallow fields, pastures, airports, and military bases. Of the seven species surveyed, Savannah Sparrows (Passerculus sandwichensis) and Bobolinks (Dolichonyx oryzivorus) were most common, occurring on 72 percent and 69 percent of all sites, respectively. Eastern Meadowlarks (Sturnella magna) were detected on 37 percent of all sites. Upland Sandpipers (Bartramia longicauda), Vesper Sparrows (Pooecetes gramineus), Grasshopper Sparrows (Ammodramus savannarum), and Henslow’s Sparrows (Ammodramus henslowii) were generally uncommon and occurred on <20 percent of the surveyed sites. We used bird distributions and geopolitical affinities to define eight sub-regions throughout the Northeast to better direct conservation actions. Each sub-region was important for different species: Grasshopper Sparrows were most widely distributed in the Finger Lakes sub-region. Upland Sandpipers and Vesper Sparrows were most abundant in the South- Central Maine sub-region, Bobolinks were most common in the Connecticut River/New Hampshire subregion, Eastern Meadowlarks were most widespread in the Mohawk Valley of New York, but we estimated the highest relative abundance in the St. Lawrence Plains. With these data, we gained a clear understanding of which areas in each state were most important for each species. This information can assist in setting conservation priorities in New England and New York and provide baseline information for the development of a comprehensive regional grassland bird management plan.