Body condition and feather molt of a migratory shorebird during the non-breeding season
Peer reviewed, Journal article
Published version
Åpne
Permanent lenke
https://hdl.handle.net/11250/3077478Utgivelsesdato
2018Metadata
Vis full innførselSamlinger
- Publikasjoner fra CRIStin - NINA [2411]
- Scientific publications [1437]
Originalversjon
10.1111/jav.01480Sammendrag
Migratory shorebirds have some of the highest fat loads among birds, especially species
which migrate long distances. The upland sandpiper Bartramia longicauda makes long distance migrations twice a year, but variation in body condition or timing of feather
molt during the non-breeding season has not been studied. Molt is an important part
of the annual cycle of migratory birds because feather condition determines flight
performance during migration, and long-distance movements are energetically costly.
However, variation in body condition during molt has been poorly studied. The objec tive of our field study was to examine the timing and patterns of feather molt of a long
distance migratory shorebird during the non-breeding season and test for relationships
with body size, fat depots, mass, and sex. Field work was conducted at four ranches in
the Northern Campos of Uruguay (Paysandú and Salto Departments). We captured
and marked 62 sandpipers in a 2-month period (Nov–Jan) during four non-breeding
seasons (2008–2012). Sex was determined by genetic analyses of blood samples taken
at capture. Molt was measured in captured birds using rank scores based on published
standards. Body mass and tarsus length measurements showed female-biased sexual
size dimorphism with males smaller than females. Size-corrected body mass (body
condition) showed a U-shaped relationship with the day of the season, indicating
that birds arrived at non-breeding grounds in relatively good condition. Arriving in
good body condition at non-breeding grounds is probably important because of the
energetic demands due to physiological adjustments after migration and the costs of
feather molt