Contemporary colonisation by waterbirds of a small dam lake in central Argentina

Abstract

A population of 80 individuals of five waterbird species which arrived at a small dam in Alta Gracia City, Córdoba, Argentina was studied. Observations over 30 years enabled us to confirm that no waterbird populations had settled there previously. The 1.4-ha and 1.5-m deep lake (known as ‘‘Tajamar’’), was built by the Jesuits in the middle of 17th century to store water for irrigation. It contains submerged vegetation of Egeria densa and Chara sp. and areas of open water and also has some species of small fish. The numbers of waterbirds were recorded at varying intervals between 2005 and 2009. The breeding of White-winged Coot (Fulica leucoptera) and Pied-billed Grebe (Podilymbus podiceps) were documented in the Tajamar, as well as the extinction and re-colonisation of Pied-billed Grebe and an increase in the number of individuals by successive immigrations of the Neotropic Cormorant (Phalacrocorax olivaceus). We also constructed the time-line for species arriving and departing.