Time-activity budgets of stiff-tailed ducks in Puerto Rico

Abstract

Habitat loss and degradation have contributed to declining populations of stiff-tailed ducks including the migratory northern ruddy duck (Oxyura jamaicensis rubida), and non-migratory masked duck (Nomonyx dominicus) and West Indian ruddy duck (Oxyura j. jamaicensis). Studies collecting time-activity budgets on waterfowl can provide important insight into habitat use, behavior, and niche partitioning. Even though the northern ruddy duck and West Indian ruddy duck are recognized as the same species, we treated them separately to appraise possible ecological differences. We recorded 24-h time-activity budgets for masked ducks (n = 142), northern ruddy ducks (n = 1,401), and West Indian ruddy ducks (n = 3,765) on the Laguna Cartagena National Wildlife Refuge in Lajas, Puerto Rico from January through April 2015 and 2016. Behaviors varied among taxa, between sexes, and between diurnal and nocturnal sampling periods. Resting and sleeping were common behaviors observed during the day and night, but all 3 taxa fed more at night with masked duck feeding more than the West Indian ruddy duck and northern ruddy duck. Northern ruddy duck and West Indian ruddy duck time-activity budgets varied with 7 of 8 behavioral categories during the day and 5 of 8 behavioral categories at night differing. Ecological differences such as body size and migration of northern ruddy ducks may account for the differences in behavior when compared to non-migratory West Indian ruddy ducks.