INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
Relationships among territory size, body size, and food availability in a specialist river duck
IPPI, SILVINA; ARÁOZ, RODRIGO; CERÓN, GERARDO; BLENDINGER, PEDRO G.; ALVAREZ, LEANDRO M.
Lugar: Collingwood; Año: 2018 p. 1 - 11
Models of territorial behaviour predict a reduction in territory size when food availability andcompetitive pressure increase. Moreover, body size can play an important role in territorialdefence. The Torrent Duck (Merganetta armata) is a river specialist that exhibits year-roundterritorial behaviour and long-term pair bonds. Food availability measured as biomass of invertebratesper unit area, territory and body size of Torrent Ducks were studied in the Andes inArgentina to test predictions of territoriality models. The availability of aquatic invertebratesdecreased with latitude, while territory size increased. As expected, territory size of Torrent Ducksshowed a negative relationship with the availability of aquatic invertebrates, a major food sourcefor Torrent Ducks. Larger males and females paired together and occupied territories with greaterfood availability. Body size may be important for both males and females for the successfulacquisition and defence of territories, especially during the non-breeding season when thecontest winner acquires or maintains the territory and the mate. Our results suggest thatTorrent Duck specialisation on fast-flowing mountain rivers leads to year-round territoriality inboth sexes, a positive correlation between territorial defence and body size, and territory sizeproportional to food availability and population density.