Vol. 43, No. 1
Allan M. Strong
Male Bobolink from a field enrolled in the project in 2014 (All photographs by Allan M. Strong)
As humans have altered land use patterns in New England, some species of birds are winners and other are losers. When you look at these changes over long time periods, some groups of species, such as grassland birds, have had it both ways. When Europeans colonized the Northeast, they transformed a landscape that was nearly 100% forested to one that by 1800 was 70% pasture and cultivated land. At the end of the Civil War, that trend started to reverse; now, roughly 67% of the Northeast is forested. As a result of these land use changes, we’ve seen the populations of grassland birds go from local rarities to common, widespread species, and then back to local rarities (see Table 1 below).
Although it is easy to correlate changes in the populations of grassland birds to changes in land use patterns, the issue is not quite that simple. The distinction between farmland and forest is straightforward, but the quality of farmland for grassland birds can vary dramatically depending on the crop and management practices. For the species of grassland birds that nest in the Northeast, most avoid row crops. Corn and soybeans in particular provide low quality habitat for these species. By contrast, forage crops, either grasses or legume-grass mixtures, can provide high quality habitat for grassland birds. Although there is some variation in habitat quality with respect to the particular species that are planted, for the most part it is the management practices, namely the frequency and timing of cutting and grazing, that have had the greatest effect on the reproductive success of grassland birds.