PREDATION OF ARTIFICIAL GROUND NESTS AT LAGUNA CARTAGENA NATIONAL WILDLIFE REFUGE, LAJAS, PUERTO RICO

Abstract

––––––––––––––––––––––––– Predation can have a profound impact on the population dynamics of a species. This impact is even greater in disturbed systems that contain exotic predators or where populations of natural predators are abnormally high. During our studies of waterfowl in Puerto Rico, we became concerned as to the possible impact of introduced rats and mongoose on nesting waterfowl. While previous publications have cited both the black rats (Rattus rattus) and the Javan (small Indian) mongoose (Herpestes auropunctautus) as West Indian whistling-duck (Dendrocygna arborea) egg predators (Birdlife International 2016), we found no published documentation to substantiate this activity. To explore this possible predation, and due to the difficulty of directly observing nests, we used motion detector cameras to monitor artificial nests baited with domesticated chicken (Gallus domesticus) eggs. Recent applications of game cameras include documentation of occurrence of rare species as well as new species records, nest predation studies, behavioral studies and activity budgets (Ellis-Felege & Carroll 2012). The use of artificial eggs in manufactured nests in conjunction with the use of game cameras is also a widely used method (Major & Kendal 1996). This paper reports on the use of this technique at Laguna Cartagena National Wildlife Refuge to determine possible egg predators of nesting West Indian whistling-ducks. West Indian whistling-ducks are endemic to the West Indies and considered “vulnerable” by Birdlife International (2016). While a systematic census has yet to be taken, it is estimated that there are at least 150 individuals on the island of Puerto Rico (Goodman et al. 2018).