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How blood parasites colonize and persist in small island bird populations

A new study highlights the complex factors at play for parasites that infect animal populations residing on small islands. The findings are important for understanding colonization and extinction as drivers of island biogeography.

Investigators who studied the mechanisms that contribute to colonization and persistence of avian malaria parasites in an island bird population found that increases in the prevalence and diversity of parasites were associated with episodes of offshore winds and less so with infected vagrant birds arriving from the mainland.

"We were surprised to find that parasites arriving with infected vagrant birds from the mainland were often absent from the local island birds," said Nicholas Clark, lead author of the Journal of Biogeography study. "We think that winds originating from the mainland may help to bring insect vectors to the island, which could maintain small numbers of malaria parasites in island birds."