Juvenile migration strategies and recruitment rates of the endangered population of Calidris canutus rufa migrating to Tierra del Fuego

GONZALEZ P; MARTÍNEZ CURCI N.; BENEGAS L; PETRACCI P; WILNER C

Congreso; 9na reunión del grupo de aves playeras del hemisferio occidental; 2022

Catches in Tierra del Fuego (TDF) between 1995 and 2010 and sightings of banded juveniles (juv) showed that not all red knot juv migrate to TDF in their first year. However there is limited knowledge of the northern sites where they stay along the continent during the austral summer. Temporal patterns during northern migration in Río Grande (TDF) non breeding grounds and Bahía de San Antonio stopover (Río Negro) show that juv migrate north later in average than adults. They reach known and recently known sites in Buenos Aires Province to Brazil, and likely unknown oversummering sites. Regarding the extreme difficulties to find nests in the Arctic; the fact that genetically mixed rufa populations with different non breeding areas share first stopover sitesafter breeding season (like Mingan Archipelago in Quebec); contagious distribution of juv; differential age strategies, and survival during first migration, estimating recruitment indexes of TDF red knots are challenging. Long term proportions of juv vs adults taking in Bahía de San Antonio before adult northern migration from 1998 to present might provide an index of good vs bad breeding season (after survival for TDF juv migrants) and they significant correlate snow cover index in their breeding grounds.