Tui De Roy/Minden Pictures/Corbis
With its spiky head plumage and intense red eyes, the southern rockhopper penguin (Eudyptes chrysocome,
seen above) looks more like a slightly predatory guy at a college party
than a committed monogamous partner. But these males mate for life,
reuniting with the same female year after year during mating season.
Despite their monogamous mating patterns, however, the birds really
don’t spend much time together, according to a new study. Using GPS
trackers mounted to the penguins’ legs, scientists monitored 16 birds
from a colony in the Falkland Islands over the course of a mating
season. The data show that males arrived at the nesting site
approximately 6 days before their female counterparts and stayed about 6
days longer. However, the short mating season means the pairs are only
united for about 20 to 30 days a year. And when they were separated, it
was usually by a large distance: During the winter months, partners were separated by an average distance of about 600 km, and one pair was observed as far as 2500 km apart, the team reports online today in Biology Letters.
Despite the large spatial segregation, their habitats were quite
similar, ruling out the possibility that partners are spending the
winter months apart because of sex-based differences in habitat or food
preference. So why don’t the birds just stick together? So far it’s
still a mystery, but the team speculates that if the birds arrived at
and left the nesting site at the same time, they’d be much more likely
to spend the winter together. But because the females show up late and
leave early, the cost of finding one another after a week of dispersing
through the open ocean might not be worth it—it’s easier to just meet
back at the nesting site next year.
Science| DOI: 10.1126/science.aad1726