Geographical distribution and population abundance of Plegadis ridgwayi, Puna ibis (Threskiornithidae) with emphasis on the populations of Peru

Abstract

The Puna ibis Plegadis ridgwayi, is a species of Threskiornithidae that inhabits Andean wetlands and makes altitudinal migrations to the coast. Data from us, GBIF, bibliographic information and the Neotropical Waterbird Census (1992 to 2015) show that this species occurs in Ecuador, Peru, Bolivia, Argentina, and Chile, with a core area in Peru and Bolivia. It is most abundant in the latter two countries, with seven and three localities with more than 1% of the biogeographic population, respectively. They are found from 0 to 5000 m altitude (with peaks at 3000 to 4500 m and 0 to 500 m). The highest incidence of records is in southern and central Peru. There are high values of environmental availability in part of the high Andean zone from Ecuador to northern Chile and northwestern Argentina, as well as the coast of central and northern Peru. The expansion of the distribution towards the Peruvian north and coast may be due to environmental availability and the deterioration of its Andean habitat. In four coastal wetlands in central Peru, up to 818 ibises were recorded in 2006, the vast majority in Pantanos de Villa and Paraíso. The number of coastal migrants seems to be related to the intensity of droughts in the highlands of central Peru. The abundance of ibis in the high Andean Lake of Junín shows a historical decline, with emphasis after the 2004-2005 drought. This distributional expansion requires investigation of possible hybridisation with the other formerly allopatric species of the genus.