Efficiency of the call-broadcast method for detecting two Caribbean-endemic columbid game species

The white-crowned Pigeon (WCPi), Patagioenas leucocephala , and the scaly-naped Pigeon (SNPi), P squamosa , are two Caribbean endemic species of patrimonial and cynegetic interest. Although both species are under the threat of habitat destruction and hunting pressure, population trends remain undocumented in a large part of their geographical range. Here, we used both the “auditory and visual” and “call-broadcast” census methods to assess the occurrence and relative abundance of both species in Guadeloupe (French West Indies). The call-broadcast method was found to be more efficient as it reduced the problem of “false absence” while increasing the probability of detection. Results from our surveys showed that both WCPis and SNPis were at low density and showed complete habitat segregation. SNPis were only encountered in rainforest, whereas WCPis could be observed at count stations located in dry and swamp forests, mangroves, agricultural lands and wet meadows. We recommend the use of the call-broadcast method for monitoring the two species on islands where they occur at low density, under which conditions distance sampling may be poorly reliable. The general relevance of the call-broadcast method to other species of pigeons and doves deserves further attention, especially to document population trends in elusive game species of conservation interest.