Introduction

Throughout most of the eastern United States and in southern Ontario, the Prairie Warbler breeds in shrubby old fields, early-stage regenerating forests, dunes, and other early successional habitats. It spends the winter in the Bahamas, on Caribbean islands, and in southern Florida, where it usually occupies habitats structurally like those of the breeding range. Before European settlement, the species was rare or absent in much of its present breeding range; following deforestation, it became widespread by the mid-twentieth century. Since about 1970, its numbers have declined in parts of the breeding range, and it is now one of the Neotropical migrant species whose status, at least in some regions and physiographic strata, is a matter of concern.

The Prairie Warbler (D. d. discolor) was the subject of a long-term study near Bloomington, Indiana (Nolan 1978), which is the principal source for this life history. Authors referred to in Nolan 1978 ordinarily will not be cited separately in this account.

The most important developments since 1978 are: 1. Concern about the decline in numbers of Neotropical migrant species has led to many accounts of the Prairie Warbler’s status and ecology in the winter range. Among these, Stacier’s (1992) study in Puerto Rico deals also with aspects of behavior and is the most comprehensive. The same concern is responsible for attention to Prairie Warbler populations in the breeding range, notably the study by James et al. (1991). 2. Prather and Cruz (1995) have summarized and added to knowledge of the breeding biology of D. d. paludicola . 3. Buerkle (1997, in press a, b) has investigated the morphological and genetic differentiation of the subspecies discolor and paludicola .