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Rats Eradicated, Seabird Haven Reborn
4 Sep
Summary
- Rats, likely arriving mid-20th century, decimated ancient murrelet population.
- A 1995 eradication effort used anticoagulant bait across the island.
- Murrelet population grew 13% annually post-rat removal.
Seabird colonies on islands, once safe havens from predators, faced new threats with the arrival of rats. Langara Island in British Columbia exemplifies this, where rats introduced mid-20th century decimated ancient murrelet populations. These seabirds, nesting in burrows, were easy prey for the rodents.
Surveys in the 1980s revealed alarming declines, with rat predation directly blamed for a nearly 90% population drop. Conservation efforts, funded by an oil spill settlement, involved bait stations placed across the island in 1995. This successful eradication was confirmed by follow-up monitoring.
The recovery of seabird populations has been swift. Estimates show a jump from approximately 13,000 birds in 1999 to 24,000 by 2004, representing about a 13% annual growth rate. Burrow-nesting species like Cassin's auklets have also begun returning to the island.
Langara Island now serves as a model for island restoration. However, recent rat re-invasions on smaller nearby islands highlight the ongoing challenge of maintaining rat-free environments.
