Life History of the Blue Ground Dove

Abstract

To the student eager to learn the roles of the sexes at the nest, the Blue Ground Dove (Claravis pretiosa) is especially attractive because of the ease of distinguishing the male from the female. This is exceptional in a family in which the sexes are usually nearly or quite alike in appearance, at least in the American species. The male is largely blue-gray, fading to white on the forehead and throat, with some prominent black bars and spots on the wing coverts. As I saw while watching at a nest at close range, his iris is deep red, bill pale grayish-yellow with a narrow black stripe along the culmen, tarsus and toes pink, claws black. In the female, the warm cinnamon-brown or russet of the central rectrices and upper tail coverts contrasts strongly with the paler, more buffy brown of the remaining upper parts, and the spots on her wing coverts are bright chestnut instead of black as in the male. Her under parts are largely grayish, tinged with brown on the chest. Her featherless parts are much as in the male, but the culmen is dark gray rather than black. The species ranges, with little or no geographic variation, from eastern Mexico to northern Argentina, and from western Ecuador to Trinidad and eastern Brazil. In Guatemala it seems to be confined to the Caribbean lowlands, although there is an old and dubious record from Retalhuleu in the Pacific lowlands (Ridgway, 1916:434). In Costa Rica it occurs not only on the Caribbean side but also in the wetter parts of the Pacific littoral, especially about the Gulf of Nicoya and to the southward, where it becomes abundant. It likewise penetrates the central highlands and has been recorded up to 5000 feet above sea level, but it was possibly more abundant in this region in former times than today, for I have never seen it there. In most parts of its range, the Blue Ground Dove inhabits regions where rain forest is the natural vegetation, yet in my experience it strictly avoids the interior of heavy forest and lives in clearings, tangled second-growth thickets, and the lighter woods. It forages largely if not wholly on the ground, where at times a dozen individuals may be seen together; often it is seen in company with other ground-foraging pigeons such as the Ruddy Ground Dove (Columbigallina talpacoti) and the White-tipped or Whitefronted Dove (Leptotila verreauxi). Yet it is not truly gregarious, for when disturbed the doves fly off in different directions, and I have never seen them travel in a compact flock. Once in February, two adult males in blue plumage kept close company about our house in the valley of El General in Costa Rica. For several days they walked over the lawn together and behaved much as though they were a mated pair. In northeastern Venezuela, however, flocks of more than 100 individuals were seen in the heavier woods bordering a stream, although generally the parties consisted of less than 10 birds. Strangely enough, in Venezuela, the Blue Ground Dove was almost exclusively arboreal and was very rarely noticed on the ground (Friedmann and Smith, 1950:469-470). The call of the Blue Ground Dove is a low, soft monosyllable, coo or, perhaps better, coot, easily distinguished from the trisyllabic kitty-woo of the Ruddy Ground Dove with which it so often associates, and from the more powerful or more mournful notes of the species of Columba, Leptotila, and Oreopeleia whose voices are heard in El General. In this region, the Blue Ground Dove is heard most frequently from January to August.