Data from: Satellite tracking of American Woodcock reveals a gradient of migration strategies

Diversity in behavior is important for migratory birds in adapting to
dynamic environmental and habitat conditions and responding to global
change. Migratory behavior can be described by a variety of factors that
comprise migration strategies. We characterized variation in migration
strategies in American Woodcock (Scolopax minor), a migratory gamebird
experiencing long-term population decline, using GPS data from
approximately 300 individuals tracked throughout eastern North America. We
classified woodcock migratory movements using a step-length threshold, and
calculated characteristics of migration related to distance, path, and
stopping events. We then used principal components analysis (PCA) to
ordinate variation in migration characteristics along axes that explained
different fundamental aspects of migration, and tested effects of body
condition, age-sex class, and starting and ending location on PCA results.
The PCA did not show evidence for clustering, suggesting a lack of
discrete strategies among groups of individuals; rather, woodcock
migration strategies existed along continuous gradients driven most
heavily by metrics associated with migration distance and duration,
departure timing, and stopping behavior. Body condition did not explain
variation in migration strategy during the fall or spring, but during
spring adult males and young females differed in some characteristics
related to migration distance and duration. Starting and ending latitude
and longitude, particularly the northernmost point of migration, explained
up to 61% of the variation in any one axis of migration strategy. Our
results reveal gradients in migration behavior of woodcock, and this
variability should increase the resilience of woodcock to future
anthropogenic landscape and climate change.