Occurrence of Anthropogenic Materials in Nests of Southern Caracara (Caracara plancus) in Northeast of La Pampa Province, Argentina

MALLET, JULIETA; LIÉBANA, MARÍA SOLEDAD; SANTILLÁN, MIGUEL ANGEL; GRANDE, JUAN MANUEL

Fort Lauderdale

Congreso; Raptor Research Foundation and Florida Ornithological Society Annual Conference; 2022

Several species of birds, including raptors, add man-made materials to build and decorate their nests. However, there is a compromise between the use of new nesting material and the increased risk of nestling mortality due to entanglement or ingestion of debris. We observed the occurrence of anthropogenic materials in 86 of 95 (90,5%) nests of Southern Caracara (Caracara plancus) in an agricultural area of La Pampa province. Caracaras mainly incorporated agricultural twine in their nests and fledglings sometimes got entangled and died. We found 2 cases of entanglement during nine years of study. Our observations add to those of Goldstein (2000) and suggest that the use of baling twine as nest material could represent an additive source of mortality for Southern Caracaras, as has been found in other bird species including raptors. Furthermore, entanglement could also affect raptors that use old caracara nests as for example Aplomado Falcon (Falco femoralis) in our study area. Southern Caracaras have an important role in agroecosystems, as scavengers that eliminate carcasses, as well as potential regulators of agricultural pest species. Campaigns to reduce the misuse and improper disposal of debris materials such as baling twine in agricultural landscapes should help to reduce this anthropogenic source of mortality in a species that although still common, shows some signs of being affected by the expansion of intensive agriculture. Further studies are needed to assess the amount of twine and other potentially harmful debris found in modern agricultural lands, and the conditions in which caracaras bring debris to their nests.