km east of the Guanica Forest which harbors the 

 largest number of the remaining birds. The Com- 

 monwealth Forest system is not immune to in- 

 dustrial pressure and over 400 hectares were des- 

 troyed between 1968 and 1973 (Kepler and 

 Kepler 1973). 



PRIORITY INDEX 



33 



DESCRIPTION 



The Puerto Rican whip-poor-will is a small 

 ground-inhabiting nocturnal bird with fluffy, 

 mottled brown, black, and gray plumage, a very 

 short bill, and very wide mouth with long bristles. 

 There is a white band across the throat and white 

 spots at the ends of the taU feathers. It is similar 

 to the North American whip-poor-will {Caprimul- 

 gus vociferus) but smaller, with much shorter 

 wings, and plumage tending more toward brown 

 and less toward gray throughout. Buff breast spots 

 are more prominent; posterior underparts are 

 deep cinnamon buff rather than pale buff. White 

 or buff tips on three outer tail feathers are greatly 

 restricted. The type specimen has the following 

 measurements: wing 135 mm; tail 112 mm; bill 

 11 mm; tarsus 16.3 mm; middle toe without claw 

 16 mm (Wetmore 1919 and Wetmore in Reynard 

 1962; J. W. Aldrich personal observations 1977). 

 Downy young are entirely reddish buff or cinna- 

 mon. Toes and legs are flesh gray. The iris is dark 

 brown. Eyes open on the day of hatching (Kepler 

 and Kepler 1973). 



Authorities differ as to whether noctitherus is 

 a distinct species or a subspecies of the North 

 American whip-poor-will (C. v. vociferous). Wet- 

 more (1919, 1922, 1927), Vincent (1966), Mayr 

 and Short (1920), Fish and Wildlife (1973), Kep- 

 ler and Kepler (1973), and Storrs Olson (pers. 

 comm. 1977) prefer to consider it a distinct spe- 

 cies, whereas Peters (1940), Bond (1945), and 

 Greenway (1958) consider it a subspecies of C. v. 

 vociferous. Vocalizations of nocfzi/ierMX, described 

 by Reynard (1962), are completely different in 

 structure from vociferous and may serve to main- 

 tain reproductive isolation between two closely 

 related species (Kepler and Kepler 1973). Storrs 

 Olson (pers. comm. 1977) is impressed by the 

 much smaller bones of noctitherus. The question 

 of correct classification has no completely satis- 



factory answer, but the preponderance of current 

 thinking seems to favor classification as two dis- 

 tinct species. 



RANGE 



This species is confined to the island of Puerto 

 Rico. It was formerly found in the moist limestone 

 forest of the northwest coast. Specimens were 

 taken in Bayamon in 1888 (Cory 1889, Wetmore 

 in Reynard 1962, Peters 1940). Bones found in 

 cave deposits near Morovis are estimated to be 

 less than 2,000 years old (Wetmore 1919, 1922, 

 1927). A bird presumed to be this species was 

 sighted at Rio Piedras (Wetmore 1916, 1919, 

 1927). AU three of those localities were in the 

 moist northwestern section of the island. More 

 recent records are all from the dry limestone for- 

 est of the southwest coast, including two popula- 

 tions at Guanica and the hills above Guayanilla 

 and one in Susua Commonwealth Forest. It prob- 

 ably once ranged over most of the coastal plain 

 on both sides of the island, but now is probably 

 confined to an area of about 3,200 hectares, or 

 approximately 3% of its probable former range, 

 the limestone regions, and only 0.7% of the total 

 land surface of the island (Kepler and Kepler 

 1973). 



Distribution of the Puerto Rican whip-poor- 

 will has remained stable since 1969 (American 

 Ornithologists' Union 1976). 



MAP 



Past and present distribution (after Kepler 

 and Kepler 1973) is shown on the following page. 



STATES/COUNTIES 



Commonwealth of Puerto Rico: 



HABITAT 



Habitat formerly included the moist limestone 

 forest that covered most of the northwestern 

 third of the island north of the Cordillera Central 

 described by Little and Wardsworth (1964) and 

 Kepler and Kepler (1973). Probably once occupied 

 the dry limestone forest on southwestern part of 

 the island as well, since they have been heard by 

 residents there at least since 1900 (Reynard 1962). 

 At present, they are known tp occur only in the 

 dry limestone forests of the southwestern area. 



