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

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

Asilomar, California, USA

Conferencia; The Third International Partners in Flight Conference – A workshop on bird conservation implementation and integration.; 2002

Partners in Flight

In Argentina there are 23 species of globally threatened birds associated with the temperate and subtropical grasslands.  The original ranges have declined precipitously for 43% of these species, and remaining populations are small and fragmented.  Habitat loss, a consequence of the change in the land use in the vast region of Argentina´s grasslands, is probably the main cause of these population declines.  The Nearctic breeding Bobolink could be also experiencing a retraction in its winter distribution in Argentina.  We have analyzed the historical and current records of this species in Argentina, and we have found: 1) the Bobolink´s winter range has decreased by at least 25%, 2) they are more regularly found in the provinces of Formosa and Corrientes, 3) at present Bobolinks primarily use natural wet grassland habitats associated to main rivers and marshes (Paraguay, Paraná, Pilcomayo and Esteros de Iberá), 4) of 45 records compiled in the past 96 years, 60% have occurred during events of El Niño Southern Oscillation (ENSO) and 85% during events of flooding of Paraguay-Paraná basin.  Natural grasslands are the main threatened habitat in Argentina (only 0.3 % of area is protected).  The decrease of natural grasslands appears to be affecting Bobolinks and as well as local residents.  The status of the Bobolink in Argentina should be revised to determine if areas of major concentration exist in grasslands in the north of the country, and to study measures for its conservation.  We recommend the cooperation between North American and Argentine ornithologists to increase the research on migrant grassland birds as Bobolink, Upland Sandpiper, Swainson´s Hawk, and other species.  This is an excellent opportunity to link the conservation needs of Neartic migrants and globally threatened resident species, such as Strange-tailed Tyrant, Black-and-White Monjita, Sporophila seedeaters and Saffron-cowled Blackbird.