The Reproductive Ecology and Population Biology of the Puerto Rican Nightjar Caprimulgus Noctitherus.

The reproductive ecology and population biology of the Puerto Rican Nightjar (Caprimulgus noctitherus), and population biology of the small Indian mongoose (Herpestes auropunctatus) were studied in Puerto Rico from 1985-1987. Six areas in Puerto Rico were selected to determine geographic distribution and estimate density. Nightjar presence was initially detected by using playback recordings; density was estimated using fixed-width transect call counts. Three areas located in northern moist limestone forest had no relict nightjars. Nightjars were found in three areas located in southwestern Puerto Rico. A total of 676 nightjars were recorded in 9,838.7 ha surveyed. These were distributed among three separate areas, Susua-Maricao (141), Guanica (347), and Guayanilla (188). The reproductive ecology of the nightjar was studied at Guanica Forest from 1985-1987. A total of 23 nightjar pairs were located. Nests were initiated between 24 February and 2 July. Courtship and laying activities were most common during the new moon and last quarter phases. Hatching dates were centered 3-5 days around the first quarter and during full moon. Nightjar nests were located in the forested uplands at Guanica Forest. Multivariate analysis of structural habitat data collected at nest and random sites revealed nightjar nesting habitat had larger amounts of leaf litter biomass, overhanging nest cover, and more open understory and midstory than randomly selected sites. Density estimates and habitat utilization of the small Indian mongoose at Guanica Forest were investigated during 1987. Mongooses were found to be significantly more abundant below 75 m than above. A strong negative correlation was obtained between numbers of mongooses and nightjars at Guanica Forest. Separate management strategies should be pursued for the nightjar on private and public lands. Within private lands, habitat acquisition of mature dry limestone forest would preserve habitat presently being threatened. Agroforestry practices that promote plantations of mahogany and native deciduous tree species should be encouraged. Habitat protection of nightjars within public lands will help to insure the continued existence of the species