Time budgets of Torrent Ducks (Merganetta armata) in the Central Andes of Colombia in relation to precipitation and food availability

Abstract

ABSTRACT Torrent Ducks (Merganetta armata) inhabit fast-flowing rivers in the Andes. Rainfall causes rivers to swell, increasing water velocity, turbulence, and turbidity. These changes may affect the ducks' foraging ability because of the harsher conditions or alteration of the aquatic macroinvertebrate resource base. We examined the relationship of Torrent Duck time budgets with food availability and rainfall in the central Andes of Colombia. Time spent foraging was not correlated with total macroinvertebrate density but was negatively correlated with density of 4 preferred families. Monthly precipitation was negatively correlated with total macroinvertebrate density but not correlated with the 4 preferred families. Time spent foraging correlated with rainfall the day before. Torrent Duck time budgets result from interactions among several factors: the ducks' foraging tactics, prey type, and river conditions that affect ducks directly, and indirectly through prey availability. Three of the 4 preferred i...