University of Washington Professor P. Dee Boersma says the ecology of penguins makes them unusually susceptible to environmental changes. Boersma said counts of the penguin populations at the 43 remaining breeding "hotspots," even once every five years, could provide valuable insights into the variability of the ocean ecosystem and the populations' viability.

But she said counts are conducted only rarely, if at all.

The task is urgent, she said, since many populations seem to be in rapid decline. Reductions of sea ice off Antarctica are threatening Adelie and emperor penguins, while temperate penguins, such as Galapagos, Peruvian and African species, are all declining.

Mining of guano, egg harvesting, commercial fishing and oil spills are the chief causes, Boersma said, although she said tourism and increasingly severe El Nino events, probably resulting from climate change, are also partly responsible.

Boersma recommends formation of a non-governmental organization to monitor major aggregations of penguins. She said such an organization could provide advance warning of urgent threats and thus make amelioration possible.

The research appears in the journal BioScience.