Data and code from: Spring migration strategies differ among three waterfowl species that winter in southern New England, USA

Data files (InterspecificInterindividualVariationData.RDS and
AnnualVariationData.RDS) and code (SpringMigStrategyCode.R) associated
with Journal of Avian Biology manuscript "Spring migration strategies
differ among three waterfowl species that winter in southern New England,
USA". These methods were used to investigate interspecific and
intraspecific variation in the spring migration strategy of 3
sympatric-wintering waterfowl. Specifically, we used GPS telemetry data to
quantify interspecific, interindividual, and annual variation in spring
migration strategies of American black ducks (Anas rubripes [n = 20]),
Atlantic brant (Branta bernicla hrota [n = 20]), and greater
scaup (Aythya marila [n = 9]) that share a common wintering area in
southern New England, USA, but differed in distance traveled between
wintering and breeding areas, breeding latitude, breeding strategy, and
breeding range size. We characterized spring migration strategies from GPS
telemetry data by quantifying ordinal spring migration initiation date,
ordinal spring migration completion date, migration duration, number of
stopovers, average stopover duration, proportion of migration time spent
in stopover, and a stopover-to-travel ratio. In the script
"SpringMigStrategyCode.R", we use one-way ANOVAs and TukeyHSD
tests to quantify interspecific variation and coefficients of variation
(CV) to quantify interindividual variation in each spring migration metric
using the "InterspecificInterindividualVariationData.RDS"
dataset. We then use normalized differences to quantify annual variation
in each spring migration metric for American black ducks and Atlantic
brant using the "AnnualVariationData.RDS" dataset. American
black ducks demonstrated the most time-minimizing spring migration
strategy, whereas Atlantic brant Branta and greater scaup demonstrated
more energy-minimizing spring migration strategies. Atlantic brant and
greater scaup also had less intraspecific variation in metrics of spring
migration strategy than American black ducks, particularly those
associated with stopover behavior, highlighting the importance of key
stopover sites for long-distance migrating species. Our findings
demonstrate that different species of sympatric-wintering waterfowl adopt
distinct spring migration strategies along the continuum from time- to
energy-minimization and have differing extents of intraspecific variation
in migration strategy, which together have important conservation
implications. Our analyses might serve as a template for considering
similar questions in comparable study systems.