1973). Comparison with estimated densities of the 

 European whip-poor-will suggests that the Guanica 

 birds may be at maximum possible densities with- 

 in their limited range. 



In the Susua Commonwealth Forest 10 km to 

 north of Guanica, and the hills behind Guayanilla 

 8 km to the east, the total population is estimated 

 at about 80 pairs or one pair per 14.1 hectares, 

 more than twice the area needed in Guanica Forest, 

 indicating that Susua forest is suboptimal for 

 whip-poor-wills (Kepler and Kepler 1973). 



The total of all known populations is estimated 

 at 450 to 500 breeding pairs, over 80% of which 

 are in Guanica Commonwealth Forest. 



The Puerto Rican whip-poor-will population 

 has remained stable since 1969 when the first ac- 

 curate data were obtained (American Ornitho- 

 logistists' Union 1976). 



REPRODUCTION 



Calling is at its peak in February in Guanica 

 Forest, suggesting that territorial encounters are 

 frequent and vigorous at that time, with possible 

 emigration of young or subordinate birds from 

 the central population (Kepler and Kepler 1973). 



In a nest found 18 June 1969, 2 chicks were 

 estimated to be 14 or 15 days old. A nest with 2 

 eggs 1 May 1971, hatched on 4 and 5 May. A nest 

 with 1 egg, 1 July and 2 eggs 3 July, took 19 days 

 for incubation (McCandless report to Kepler and 

 Kepler 1973). Nesting occurs mid-April through 

 early July. May and June probably are peak nest- 

 ing months, but calling is maintained from Febru- 

 ary to May with low numbers calling in July in 

 Guanica Forest. There may be two broods per 

 year, although this has not been verified. 



No nests are built; eggs are laid directly on 

 leaf litter under scrub vegetation with canopy 4 

 to 6 m high (never in open areas). 



Young wander a short distance (20 cm) from 

 the nest on the third day after hatching and ir- 

 regularly farther thereafter. They are able to fly 

 on the 14th day. 



Based on 3 nests, the clutch size is 2 eggs laid 

 on successive days. Eggs are buffy brown with 

 numerous brownish purple spots over the entire 

 surface, and are only moderately cryptic against 

 the substrate (Kepler and Kepler 1973) of dry 

 leaf litter. Protective coloration of the incubating 

 bird provides safety from predators. The in- 

 cubating bird remains on eggs even when closely 



approached. When driven from nest or chicks, 

 adults engage in distraction display by flapping 

 wings, spreading tail and opening mouth while 

 on the ground (Kepler and Kepler 1973). 



MANAGEMENT AND CONSERVATION 



Although Susua and Guanica Commonwealth 

 Forests are nominally protected, the tremendous 

 industrial expansion to the east and possibly real 

 estate development to the west threatens them 

 both. These forests must be given additional 

 recognition and protection from human use and 

 domestic predatory and herbivorous animals, par- 

 ticularly goats, to assure the continued existence 

 of the Puerto Rican whip-poor-will (Fish and 

 Wildlife Service 1973; Kepler and Kepler 1973). 



A recent favorable action has been the ruling 

 by the Environmental Quality Board that any 

 new industrial growth east of Guanica cannot be 

 accompanied by increased air pollution. Emissions 

 from existing oil refineries would have to decrease 

 to accomodate new growth. Also, an attempt to 

 use Guanica as a sanitary landfill site has been 

 temporarily shelved. 



The most recent serious threat is a proposed 

 condominium complex on Punta Ballena, a pri- 

 vately owned tract 3.2 km south of the center of 

 Guanica Forest. Several thousand people would 

 be housed within easy walking distance of the 

 whip-poor-wills, necessitating road and commer- 

 cial development with the expected onslaught of 

 people, cats, rats, and mongooses and the danger 

 of fire (American Ornithologists' Union 1976). 



The proposed sanitary landfill at Guanica 

 Forest and highway development along its 

 southern boundary remain threats (H. Rafael 

 pers. comm. 1977). 



AUTHORITIES 



Cameron B. Kepler and Angela K. Kepler 

 R. R. Maalaea Rd. 

 Kula, Hawaii 96709 



Ricardo Cottee 



U.S. Fish and Wildlife Service 



Atlanta, Georgia 



Warren King 

 Smithsonian Institution 

 Washington, B.C. 



Dr. James B. McCandless 

 P.O. Box 1060 

 Mayaquez, P.R. 00709 



