Determining the wintering range of broad-winged hawk (buteo platypterus) in South America using citizen-science database

Abstract

Several species of raptors that breed in North America migrate to the southern hemisphere during the non-breeding period. The Broad-winged Hawk (Buteo platypterus) is one of them, and its wintering distribution reaches the north and central part of South America, although there are published records for the species in Argentina and southern Brazil. We did an exhaustive search of records of the Broadwinged Hawk for South America, using bibliography, citizen-science initiatives, personal communications, and own records. We obtained 4025 georeferenced records for the 1879-2017 period. Both the numbers of records per year and the geographical range of the species have apparently increased in recent years. We also obtained the first record for Misiones province in Argentina and for Espírito Santo state, in Brazil. The wintering range of this species is estimated to cover 12.5 million km2 of the north central part of South America, including southern Brazil and northern Argentina. While it is possible that the range has expanded 700 km southwards recently, with the data available it is not possible to disentangle this possibility from changes in the distribution of bird observers.