Facing the challenge: scheduling departure date to an oversea non-stop flight from Chiloé to North America based on sex and apparent body condition

ARAYA, VALERIA; MARTINEZ CURCI NATALIA; NAVEDO, JUAN

Congreso; 8va reunión del grupo de aves playeras del hemisferio occidental; 2019

Audubon Panamá, WHSG

Accurate scheduling of departure from non-breeding areas back to breeding grounds is crucial to complete a successful migration. It is indeed one of the most important decisions that long-distance migratory shorebirds have to face, especially those that make no or few stops to refuel once in route. However, due to the scarcity of marked individuals and the difficult access to high-altitude non-breeding areas, few studies have analyzed the individual departure scheduling of long-distance migratory shorebirds, and none of them explored sexual differences. Here we present information about male and female departure dates during 2019 season using a marked population of Hudsonian Godwit (Limosa haemastica) that spent the non-breeding season in a particular bay of Chiloé island, Southern Chile. Based on 16 surveys made every 2 days with constant effort within the last part of the non-breeding season, we made 331 accurate resightings of 102 individual godwits. After removing the birds resighted only once, we estimate departure dates (±1 day) of 69 godwits. Sex was defined using a method that incorporates molecular techniques for sexing by means of bill length. Breeding plumage extension and abdominal profile were use as measures of individual body condition. Our data showed that most individuals departed from this bay in Chiloé to North America during a short time-window of less than one week. There were significant differences in the individual condition when males and females departed. To our knowledge, this is the first study that addresses sexual patterns in departure decisions of long-distance migratory shorebirds.