The Puerto Rican nightjar or Puerto Rican Whip-poor-will (Antrostomus noctitherus) is a bird in the nightjar family found in the coastal dry scrub forests in localized areas of southwestern Puerto Rico. It was described in 1916 from bones found in a cave in north central Puerto Rico and a single skin specimen from 1888, and was considered extinct until observed in the wild in 1961. The current population is estimated as 1,400-2,000 mature birds. The species is currently classified as Endangered due to pressures from habitat loss.
The Puerto Rican Nightjar is endemic to Puerto Rico where it is rare to locally common in and around the Guánica State Forest (Raffaele and others 1998, Vilella and Zwank 1993). Historically, its distribution may have included the northern karst from where it was originally described, but currently it is mostly restricted to southern Puerto Rico from Cabo Rojo to Guayama (Reynard 1962, Vilella and Zwank 1993). Its distribution includes privately owned lands between the Guayanilla-Peñuelas area (USFWS 2017, Vilella and Zwank 1987), as well as the Susúa (Oberle 2018, Vilella and Zwank 1993) and Maricao (Delannoy 2005, Vilella and Zwank 1993) State Forests, and other localities including La Parguera and Sierra Bermeja in Lajas (Oberle 2018, Vilella and Zwank 1993), and Guaniquilla, El Combate (Raffaele and others 1998), and Peñones de Melones in Cabo Rojo (Díaz-Méndez and Vicenty 2005). Typical habitat for this species includes xeric limestone forests along the southwestern coast of the island, dry deciduous and semideciduous forests with dense leaf litter, evergreen forests, and sometimes riparian areas and plantations (Oberle 2018; Raffaele and others 1998; Vilella 1989; Vilella and Zwank 1987, 1993). The atlas fieldwork yielded a total of 146 records within 46 hexagons or 10 percent of the 479 total hexagons (see map). Of the 46 hexagons where this species was found, breeding met the atlas definition of confirmed in 11 percent (5) of the hexagons, probable in 35 percent (16), and possible in 52 percent (24), while the species was observed in 2 percent (1) of the hexagons but without evidence of breeding (see map). Puerto Rican Nightjar distribution. The map shows the highest breeding code by hexagon and overlaying the ecological life zones in Puerto Rico. Note: percentages may not total 100 due to rounding. 77Puerto Rican Nightjar/Guabairo
Previously published reports indicate that the Puerto Rican Nightjar breeds from late February to early July (Raffaele and others 1998). The nesting occurs directly on a dense leaf litter layer of the forest fl oor, often under a low bush (Biaggi 1997, Oberle 2018, Raffaele and others 1998). Atlas results show that this species breeds from December through August with the most breeding activity from February to May (see chart). Breeding activity peaks during May, and it mostly takes place within the subtropical dry forest life zone (60 percent of the hexagons) (see table). It also breeds within the subtropical moist and subtropical wet forest life zones at higher elevations (36 and 4 percent of hexagons, respectively) (see table and map).
The Puerto Rican Nightjar is currently listed as Endangered by the IUCN (BirdLife International 2016). Threats to the population include habitat destruction, as well as the presence of nest and chick predators such as feral cats (Felis catus), mongooses (Herpestes auropunctatus), and fire ants (Solenopsis spp.) (Oberle 2018, Raffaele and others 1998). Locally, this species is classified as endangered by local and Federal laws (PRDNER 2016 and USFWS 1973, respectively). In Puerto Rico, the Puerto Rican Nightjar has a protected habitat in land of 14 percent or 155 km2 of the total area covered by the hexagons where evidence of breeding was found for this species (1079 km2).