Reproductive ecology and behaviour of the Puerto Rican Nightjar Caprimulgus noctitherus

Abstract

The reproductive ecology and behaviour of the endangered Puerto Rican Nightjar Caprimulgus noctitherus was studied at the Guanica Forest, located in south-western Puerto Rico. From 1985 to 1987 a total of 23 nightjar nests were located. Nests were initiated between 24 February and 2 July. Nightjar males were mostly responsible for parental duties. An elaborate nest-relief ceremony was discovered for this species. Courtship and laying activities were most common during the new moon and last quarter phases. Hatching dates were centred 3-5 days around the first quarter and during full moon. A total of 87% of the nests were successful in producing at least one fledgling. Locomotory activity of radio-tagged nightjar males was higher during periods of twilight, and averaged 61.5 m/movement. Area of primary utilization (i.e. home range) averaged 5.2 ha/nightjar during the period of transmission. A large portion of the species's current range is privately owned forestland that could be subjected to changes (i.e. deforestation), rendering it useless for nightjars. The sedentary nature and nesting habits of this species make it particularly sensitive to the physical and ecological alteration of mature dry forest. Conservation of existing reserves, reforestation of disturbed areas with native and selected plantation species, and acquisition of privately owned tracts of mature dry limestone forest will help to insure the long-term survival of the species throughout its range. © 1995, Birdlife International. All rights reserved.