INTRODUCTION Peregrine Falcon standing on its prey, a pigeon; Jones Beach St. Pk., LI, NY; Feb. About the photographs Figure 1. Distribution of the Peregrine Falcon in North and Middle America and the western West Indies. This species also breeds in South America and locally worldwide. American birds winter from the dashed line south throughout the U.S. (except the Great Basin, Great Plains and Appalachians), Middle America, the West Indies, and South America. See text for details. Peregrine Falcom juvenile on a Swallow box; Jamaica Bay WR, Queens, NY; Feb. One of the most widely distributed of warm-blooded terrestrial vertebrates, the Peregrine Falcon occurs from the tundra to the Tropics, from wetlands to deserts, from maritime islands to continental forests, and from featureless plains to mountain crags—it is absent as a breeder only from the Amazon Basin, the Sahara Desert, most of the steppes of central and eastern Asia, and Antarctica. This depth and breadth of habitat reflects a prodigiously catholic diet that includes many hundreds of species of birds, some bats, and a few rodents, and yet a commonality of ways in which Peregrines pursue them. The presence of this species in the pristine landscape has no doubt influenced the morphological and behavioral evolution of countless avian species. Even so, some populations of Peregrines are food specialists; in the Pacific Northwest, for example, enormous numbers of a few marine bird species support one of the densest-known Peregrine populations. The often-held image of the Peregrine as a symbol of wilderness diminishes when one sees this falcon breeding on metropolitan bridges and urban skyscrapers or watches tundra migrants on their neotropical nonbreeding grounds speeding along traffic-jammed boulevards at streetlight height in Rio de Janeiro, Brazil, or Buenos Aires, Argentina, chasing bats at sunset. Indeed, a Peregrine is always worth watching; humankind has long admired this species as nature’s perfect aerodynamic performer and as a strikingly beautiful bird. Few other North American species held as high a scientific and public profile in the twentieth century. Among the most studied of wild avian species, with a bibliography exceeding 2,000 primary scientific titles, the Peregrine was a cause célèbre of the environmental awakening of the 1970s. Ironically, its popularity increased with its disappearance as a breeding species from most of eastern North America and parts of Europe and its marked reduction over most of the rest of North America, Europe, and (probably) northern Asia. Although it was thought in many circles to be a globally declining and endangered species, this was never so. The Peregrine was, however, greatly harmed, along with other birds of prey and some marine birds, by the widespread use of persistent chemicals that lowered reproduction and survival rates. By 1970, the Peregrine was federally protected in the United States, and the chemical culprits were virtually banned in North America by 1972. Peregrines have since made a strong recovery, aided in part by restorative management. The name Peregrine means “wanderer,” and northern-nesting Peregrines are among North America’s long-distance migratory species, some moving 25,000 kilometers annually. It is difficult to characterize the resident status of the Peregrine as a species. While most spend but a few months over the northern third of their North American breeding range, some populations remain sedentary; for example, mated pairs can be seen sitting together on their snow-covered breeding ledges in January in the Aleutian Islands. Although most North American Peregrines used to nest on cliffs, their establishment as urban denizens over the past 2 decades (Frank 1994, Cade et al. 1996) has been dramatic and highly publicized in the popular press. Increasingly, they use other unconventional nest sites such as old Common Raven (Corvus corax) nests on electric pylons, Osprey (Pandion haliaetus) and cormorant (Phalacrocorax spp.) nests on channel buoys, abandoned Bald Eagle (Haliaeetus leucocephalus) nests along the Pacific Coast, an emergent dead tree snag in California, and special towers in salt marshes. Recently they have even extended their nesting range to such an unexpected location as Cuba (Regalado and Cables 2000). top DISTINGUISHING CHARACTERISTICS Peregrine Falcon in flight; Cape May, NJ; Oct. Medium to large falcon ( View Video). Total length: male 36–49 cm, female 45–58 cm. Adult with bluish-gray upperparts (becoming more blackish on head), variable-width blackish facial stripe extending down from eye across malar (“malar stripe,” used here, or “moustache” of some authors), this stripe usually set off by pale auriculars or “cheek,” but pattern sometimes obscured if cheek all dark; underparts whitish, grayish, or buffy with variable amount of blackish spotting and barring; under wing and under tail surfaces barred pale gray and black. Immature similar but upperparts vary from pale to slate or chocolate brown and underparts buffy with blackish streaks (vs. bars). Sexes best distinguished by size, with female 15–20% larger and 40–50% heavier than male; normally no size overlap between sexes within a given subspecies. Female also more heavily marked below (e.g., broader and fewer bars) on average than male (see Appearance and Measurements and Appendix 2). No seasonal variation in plumage other than muted or lessening of colors as feathers wear, but bare parts of male brighter in breeding season. Among large North American falcons, female Aplomado Falcon (Falco femoralis) is nearly the size of male Peregrine, but not stocky, heavy-looking, and more kestrel-like with long tail. Peregrine more easily confused with Gyrfalcon (Falco rusticolus) and Prairie Falcon (Falco mexicanus). Distinguished from Gyrfalcon by generally smaller size, wings narrower at base and more pointed, comparatively less rounded at tip (primary tip formula 9 > 10 > 8 > 7, in Gyrfalcon 9 > 8 > 10 > 7), shorter, less tapered tail; when perched, wing-tips reach nearly to end of tail (wing-tips do not reach tail tip in Gyrfalcon). Adult Peregrines usually have more contrasting dorsal-to-ventral colors, under wings not 2-toned, and cheek with more defined malar-stripe (entire cheek may be black, lacking pale auricular, in some). Immature Peregrine of race F. p. pealei most easily confused with Gyrfalcon, but proportions, especially wing shape, different. Distinguished from Prairie Falcon by being generally darker, less pale brown (Prairie Falcon “sandy” in color; however, many immature F. p. tundrius and some immature w. anatum also pale), more contrastingly patterned dorsal to ventral, proportionately shorter tail, and lacking the Prairie Falcon’s contrasting dark center of under wing (broadest in axillaries) seen in flight. Peregrine also has deeper, more fluid, and less stiff wing-beat than Prairie Falcon (Clark and Wheeler 1987, Dunne et al. 1988). Hybrid falcons bred for falconry (e.g., Peregrine Falcon * Prairie Falcon, Peregrine Falcon * Gyrfalcon, and various backcross mixtures [difficult to characterize]) sometimes lost to the wild and are readily confused with Peregrines (see Conservation and management, below). DISTRIBUTION THE AMERICAS | OUTSIDE THE AMERICAS | HISTORICAL CHANGES | FOSSIL HISTORY THE AMERICAS Breeding range Figure 1. Formerly extirpated from much of original range by synthetic organic chemicals such as DDT (see below and Conservation and management, below); reoccupancy and restoration still incomplete in 2001, especially in central and s. Canada and midwestern and e. U.S., where much of distribution is urban, but progressing rapidly (Enderson et al. 1995a). Thus, distribution as given is subject to change. Following information as of 2000–2001, provided by federal, provincial, and state agencies, recovery-team members, and individuals documenting recovery. Alaska, Canada, and Greenland. In the west from w. Aleutian Is. (Attu 53°N, 172°35’E) east through Aleutians and Alaska Peninsula, then north along coastal w. Alaska, where spotty but with local concentrations such as Norton Sound (64°N; absent from Nunivak, St. Matthew, Pribilof, St. Lawrence, and Diomede Is.), to North Slope of Alaska (about 70°N; locally, largely riverine, but moving into coastal plain around lakes north of 70°; R. Ritchie pers. comm.); Yukon Territory, Northwest Territories, and Nunavut locally north to about 73°30'–74°N in parts of Banks I., Victoria I., Melville I. to 75°N; Bothia Peninsula to about 72°N, to Baffin I. and then to ice-free parts of w. Greenland from Thule (Qaanaaq), about 76–77°N (scarce; Burnham 1996) south around tip and north on east side at least to Angmagssalik (65°40’N), although seen as high as Thomsen Land (75°N) and Germania Land (76°50'–77°N; Boertmann 1994), in breeding season. Then southward through Alaska, Yukon (spotty and local), Northwest Territories, Nunavut, British Columbia (poorly documented inland), n. and central Alberta, Saskatchewan (Saskatoon and Regina, where urban breeders), Manitoba (Winnipeg and Brandon; urban sites), s. Ontario (e.g., along Great Lakes), s. Quebec (along St. Lawrence River), Labrador (mainly coastal; Todd 1963; Canadian Wildlife Service 1988; G. Chilton, G. A. Court, U. Ban-asch, G. Holroyd pers. comm.). Absent as breeder from Newfoundland. United States. Locally (see Fig. 1) through northern tier of states, most midwestern and eastern states. Many introduced into urban areas (e.g., Milwaukee, WI; Chicago, IL; Fort Wayne, IN; New York, NY); spotty and local (urban) in midwestern states (e.g., Nebraska, Missouri, Iowa); spotty and local in most eastern states (e.g., New England, Pennsylvania, New York, New Jersey, Maryland, Delaware, Virginia, N. Carolina, S. Carolina, Alabama; Burnham 1995; J. Castrale, M. Amaral, C. Koppie pers. comm.). Widely in western states (e.g., most of Utah, Arizona, w. Colorado, w. and n. California; see Fig. 1), but absent from N. Dakota (although bred in urban Fargo, ND, in 2001; B. Tordoff pers. comm.), Florida, Oklahoma, Arkansas, Alabama, Mississippi, Louisiana, Texas (except sw. Rio Grande region), and Nevada (except along borders with Utah, California, and Arizona; Burnham 1995, TJC, CMW, WGH).