Sex-specific migratory behavior in a marine predator results in higher risks to females


Summary written by Sofia Denkovski

Protecting Migratory Species

  • Migratory species often show spatial/temporal segregation of sexes, which can lead to sex-biased mortalities.
  • Sea-birds commonly exhibit sexual segregation in migration, winter, and sex-biased mortality. Magellanic penguin females have higher mortality than males in winter.
  • To protect these species, an understanding of distributions of the sexes is essential.

Sexual Segregation of Magellanic Penguins

  • Females stayed approx. 47 km closer to shore than males.
  • Females were found in northern areas more than males.
  • Females departed the colony earlier than males.
  • Mates did not overlap at sea.

Effects of sex-biased distribution on females

  • Increased likelihood of gill-net entanglements and beach strandings.
  • Increased effects from pollutants in the Rio de la Plata river plume.
  • Northern foraging areas are utilized by various marine mammals, sea turtles, sea birds, etc.

What does this tell us?

  • Northern and near-shore distribution of females increases their vulnerability to pollution, entanglement, and harmful algal blooms
  • Further protection of female non-breeding and migration areas is essential!
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