Migration and molt of Phalaropus tricolor: integrating information from observations and open access databases

ADRIAN S. DI GIACOMO; CASTELLINO, M. ; BUCHER, E. H.

Puerto Iguazú

Congreso; Ornithological Congress of the Americas; 2017

Aves Argentinas

We present a review of the migration and molt patterns of Wilson's phalarope (Phalaropus tricolor) for Central and South America. We use personal observations and information from two open access ornithological databases (eBird and Ecoregistros) between 2015 and 2017. From a total of 1832 records available, 207 records had images that allowed the classification of individuals into one of the following categories of plumage: basic, intermediate or alternate. The data obtained were grouped in both temporal and latitudinal ranges to show the migratory movements and the progression of molt. The regularity of annual molt pattern at continental level was confirmed, and new information about the pre-alternate molt of phalaropes is reported. Phalaropes arrive at their main non-breeding sites in September in basic plumage. In February begins the pre-alternate molt of body feathers. By the end of the month begins the migration towards breeding grounds that extends until April, when most of the individuals exhibit alternate plumage at the time of departure. Finally, we report the record of a significant number of individuals that remained during the austral winter in Argentina. Although birds did not migrate, they complete their annual molting cycle. This represents the first case of an important over-summering population reported for the species in its non-breeding grounds.