Research published in Vol. 126, Iss. 3, pg. 579 of The Auk has some interesting implications for habitat conservation for migrating bird species here in eastern North America. In short, during Spring and Fall migration, migrants showed no preference for stopover locations based on distance from a continuous, connected (river corridor) habitat, nor were they more likely to be concentrated in one forest patch over another. Plainly, the migrating birds appear to show no preference for connected habitats versus fragmented ones. Clearly, if this is the case, birds are using other criteria to select where they stop while migrating.
What is interesting, and not surprising, is the finding that during Fall migration, birds do select habitat described as “early succession forest” with high density of native and non-native fruit-bearing trees and shrubs. In the cannon of conservation, habitats that are fragmented or in the early stages of succession are seen as lower quality when compared to continuous and stable habitats. And this may still be the case when it comes to nesting (less nest predation in larger forests, for example)—but it would seem as though we might need to re-evaluate the assumption that these younger, more fragmented landscapes are of little or no use to birds and ultimately, bird conservation.
As migratory stopovers, it would seem that all forested landscapes—no matter how mature—are important.