Introduction

The vivid red and black male Scarlet Tanager, a harbinger of spring in eastern North America, is among the most colorful and striking of our breeding birds. The smallest of the four species of the genus Piranga that breed north of Mexico, it is a long-distance Neotropical migrant, annually making the journey between northwestern South America and the eastern United States and southern Canada. In eastern North America, its breeding range closely corresponds to the boundaries of the Eastern Deciduous Forest Biome, where despite its brilliant coloration it is often overlooked because of its unobtrusive and secretive behavior. Fortunately its hoarse, burry song and frequently uttered Chip-Churr Calls are quite distinctive and alert us to its presence high in the canopy.

As a species of the forest interior, it is sensitive to forest fragmentation, suffering high rates of predation and brood parasitism in small forest plots and often absent completely from plots less than a minimum size. Breeding Bird Surveys since 1966 indicate a relatively stable population, but with a slight decline in areas of intensive agriculture. In such landscapes where the forest is highly fragmented, the species appears to exist as a dynamic mosaic of source and sink populations.

This tanager is monogamous and aggressively territorial throughout its range, seldom occurring in high densities. While establishing its territory and early in the breeding season, it sings incessantly from perches in the mid- to upper canopy. It is largely insectivorous, foraging heavily on the larvae of Lepidoptera and a variety of adult insects by hovering and gleaning. Much of the information about this species is anecdotal, but important information is available concerning nesting, parental behavior, predation, and development of young from a study in s.-central Michigan (Prescott 1965). Recent studies have improved our understanding of the Scarlet Tanager’s foraging microhabitat (Maurer and Whitmore 1981, Sabo and Holmes 1983), foraging strategies (Holmes 1986, Cooper et al. 1990), and various aspects of its vocalizations (Shy 1984a). Several excellent studies have recently clarified aspects of its local and regional population dynamics in fragmented forests (Robbins et al. 1989, Robinson 1992, Brawn and Robinson 1996, Roberts and Norment 1999, Villard et al. 1999) and the effects of forest fragmentation on abundance over its entire range (Rosenberg et al. 1999).