ABSTRACT

Despite the broad environmental tolerance of the Military Macaw (Ara militaris) reflected in its wide ecological distribution, most surveyed populations in the few studied breeding areas in Mexico present <100 individuals. Although records of the species include several regions across the country, most groups recorded include <50 macaws. Prior to this report, the largest known breeding Mexican population documented was the Tehuacán-Cuicatlán nesting colony with 100 macaws. Over the last 8 years, we surveyed the macaw population nesting in tropical coastal forests located in the southern portions of Bahia de Banderas, the bay where Puerto Vallarta in Jalisco is located. We systematically assessed the macaw population by counting the flocks occurring in 3 forested areas located 20–37 km apart and assumed to harbor different and independent macaw groups. The macaw abundance was surveyed during 35 consecutive months from February 2012 through December 2014. Based on location of the surveys, the timing of the observations, and the flight direction of the 3 distinct macaw groups, we inferred that each uses different foraging, roosting, and nesting areas. Higher abundance for each population was observed during February–May each year, contrasting with a low level of activity observed during the summer months of July–August. We assumed that the macaws exhibit nomadic behavior outside the region during summer. The 3 populations may constitute a metapopulation that congregates after the fledglings acquire flying skills during the initial months of the nonbreeding season on the 3 different areas. During March 2013, the highest concentration was registered in the Yelapa region, where 215 macaws were observed in a colonial roost, constituting the largest aggregation documented for the species. If data from the 3 populations surveyed are combined, the estimated number of macaws is 363 birds for 2014. Based on our data, we believe the region harbors a vital population for the long-term survival of the Military Macaw in central western Pacific and Mexico.

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