Comparative foraging behaviour of sympatric Humboldt and Magellanic Penguins reveals species-specific and sex-specific strategies

A RAYA REY; K PÜTZ; A SIMEONE; L HIRIART BERTRAND; R REYES ARRIAGADA; V RIQUELME; B LÜTHI

EMU

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2013 vol. 113 p. 145 - 153

0158-4197

How closely related marine organisms mitigate competition for resources while foraging at sea is not wellunderstood, particularly the relative importance of interspecific and intraspecific mitigation strategies. Using location andtime?depth data, we investigated species-specific and sex-specific foraging areas and diving behaviour of the closely relatedHumboldt (Spheniscus humboldti) and Magellanic (S. magellanicus) Penguins breeding in sympatry at Islotes Puñihuil insouthern Chile during the chick-rearing period. The average duration of foraging trips was <20 h and did not differsignificantly between species or between sexes of each species. Magellanic Penguins made significantly deeper and longerdives than Humboldt Penguins. Males of both species made significantly longer dives than females. Total distance travelledper foraging trip was significantly greater for males than for females, and females made more direct trips (less sinuous) thanmales. Foraging effort was concentrated in waters up to 15 kmto the west and south-west of the colony. The overlap in densitycontours was lower between species than between sexes within a species. In general, dive characteristics and foraging areasdiffered more between Magellanic and Humboldt Penguins than between the sexes of each species. In contrast to the findingsof studies of flying seabirds, the foraging behaviour of these penguins differs more between species than between sexes.