Ground versus above-ground nesting of Columbids on the satellite cays of St. Croix, US Virgin Islands

We examined the incidence of ground versus above-ground nesting of columbids on four nearshore cays off St. Croix, US Virgin Islands. Roof rats ( Rattus rattus ) occurred on two cays (Protestant Cay, Ruth Island), whereas rats were absent from the two other cays (Buck Island, Green Cay) in 2002-2003. We discovered 6 ground nests (2.1%) of three columbids out of 288 nests of five columbids, including the first documented record of ground nesting by the Scaly-naped Pigeon ( Patagioenas squamosa ). The proportion of ground nests on cays with or without rats was similar (1.5% versus 3.4%). Despite flexible nest-site placement of ground and above-ground nests of columbids on inhabited and uninhabited cays off St. Croix, the low number and restriction of ground nests to early successional habitats suggest that columbids may prefer breeding above-ground when suitable nest-sites are available in more mature habitats regardless of the presence or absence of rats.  Nous avons compares la nidification au sol par rapport a la nidification au dessus du sol des colombides sur 4 ilots de St. Croix, Iles Vierges Americaines. Le Rat noir ( Rattus rattus ) est present sur 2 ilots (Protestant Cay, Ruth Island), alors qu’il etait absent des deux autres (Buck Island, Green Cay) en 2002-2003. 6 nids (2,1%) de 3 especes de colombides sur les 288 repertories de 5 especes, ont ete decouverts au sol, dont la premiere observation confirmee de nidification au sol du Pigeon a couronne blanche ( Patagioenas squamosa ). La proportion de nids au sol etait la meme sur les ilots avec ou sans rat (1,5% vs. 3,4%). En depit de la localisation souple du choix des sites de nidification, au sol ou non, des colombides sur les ilots habites ou non de St. Croix, le nombre reduit et la localisation des nids au sol aux premiers stades de la succession des habitats, suggere que les colombides preferent nicher au dessus du sol quand des sites adequats sont disponibles dans des habitats plus evolues, qu’il y ait ou non presence de rats.