Status and conservation of the Bobolink (Dolichonyx oryzivorus) in Argentina.

DI GIACOMO, ADRIÁN S.; DI GIACOMO, ALEJANDRO G.; CONTRERAS, JULIO R.

Bird Conservation Implementation and Integration in the Americas.

U.S. Department of Agriculture

Lugar: Albany, CA; Año: 2005; p. 519 - 524

The nearctic breeding Bobolink (Dolichonyx oryzivorus) is experiencing a decline in North America. Some authors suspect winter survivorship in South America could be responsible for the decline. We analyzed historical and current records of this species in Argentina, and found: 1) the Bobolink´s winter range has decreased by at least 25 percent; 2) they are more regularly found in the provinces of Formosa and Corrientes; 3) at present Bobolinks primarily use natural wet grassland habitats associated with main rivers and huge marshes (Paraguay, Paraná, Pilcomayo and Esteros de Iberá); and 4) of 45 records compiled in the past 96 years, 60 percent have occurred during events of El Niño Southern Oscillation (ENSO) and 85 percent during events of flooding of Paraguay-Paraná basin. Natural grasslands are the main threatened habitat in Argentina (only 0.3 percent of area is protected). The decrease of natural grasslands appears to be affecting Bobolinks as well as local residents. The status of the Bobolink in Argentina should be assessed to determine if areas of major concentration exist in agricultural crops and grasslands in the north of the country, and to identify measures for its conservation. We recommend cooperation between North American and Argentine ornithologists to increase the research on migrant grassland birds such as Bobolink, Upland Sandpiper (Bartramia longicauda), Swainson´s Hawk (Buteo swainsoni), and other species. This is an excellent opportunity to link the conservation needs of nearctic migrants and globally threatened resident species that have declined precipitously, such as Strange-tailed Tyrant (Alectrurus risora), Black-and-White Monjita (Heteroxolmis dominicana), Saffron-cowled Blackbird (Xanthopsar flavus) and seedeaters (Sporophila spp.).