Ground Nesting by Black-Bellied Whistling Ducks on Islands in Mexico

Abstract
We found 496 ground nests of black-bellied whistling ducks (Dendrocygna autumnalis) on 3 small (4.3-15.8 ha) islands in Laguna laNacha, Tamaulipas, Mexico, in July and August 1987. Overall nest density was 15.7/ha and nest success was 28.3-41.7%. We could not follow all nests to completion, but all observed nest loss (58.4%) was due to desertion, and 41.8% of nests were dump-nests. Pricklypear cactus (Opuntia spp.) was the most preferred nest cover. Causes of island ground nests probably reflected selection of a nesting environment free from mammalian nest predators and flexibility in nesting behavior by blackbellied whistling ducks.