This post comes to us from biologist Steve MacLean, director of The Nature Conservancy’s Bering Sea Program in Alaska.

Last summer, when biologists walked along the rocky cliffs on Rat Island, one of more than 2,000 islands in Alaska’s Aleutian chain, they encountered an eerie silence. This place should have been a cacophonous and lively melee of bird calls. 

The reason for the silence? Invasive rats. They colonized the island after a Japanese fishing vessel wrecked against its rocky shore in 1798. Their numbers multiplied, and for more than two centuries the voracious rats have preyed on bird eggs and young chicks. The birds gone, silence spread from shore to shore.

This summer, biologists discovered something new at Rat Island: encouraging signs of bird life. The reason? A seabird restoration project is at work.  

Over the course of a week-and-a-half in the fall of 2008, our project team, led by the U.S. Fish and Wildlife Service, Island Conservation and The Nature Conservancy, broadcast bait across the island. Our objective was this: removing the rats and reclaiming the island as productive seabird breeding habitat.

We’ve received initial evidence that the invasive rats from Alaska’s remote Rat Island are no more. Biologists report three peregrine falcon nests. Several nesting bird species — black oystercatchers, ptarmigan, Aleutian cackling geese and others — appear to be more abundant. This means that the lively din of puffins, auklets and other birds may soon return.

But with the good news of returning nests comes an unexpected report.

In June, project biologists reported the discovery of some dead birds: Most notably, 43 bald eagles and 213 glaucous-winged gulls.

It’s an absolutely shocking discovery. In Alaska, where the population of bald eagles numbers 50,000, we have an undeniable attachment with eagles — that eagles have died is deeply disappointing to us.

To learn more, we’ve expedited tissue samples to the National Wildlife Health Center in Madison, WI. We expect pathologists’ results from these tests in coming weeks.

In the meantime, it leaves us with a lot of time for serious soul-searching. Was our own restoration project responsible for this devastating loss? What’s the future of Rat Island?

For now, we know the project was responsible for at least some of the bird deaths. This deeply saddens us, and reinforces our commitment to ensuring that our projects provide the maximum benefit to Alaska’s biodiversity and minimize the risk associated with each project. While no restoration project like this one can be entirely risk free, we know we can learn from this project to ensure that all restoration projects around the world are conducted as safely and effectively as possible. 

As for the future of Rat Island, we’re optimistic. For more than 200 years, invasive rats have ruled this remote island, essentially killing off the puffins, auklets, sandpipers, ducks and songbirds that would normally nest in what is otherwise optimal habitat.

The arc of experience tells us our optimism is warranted. Worldwide, more than 300 similar rat eradication efforts have proved successful. Nonetheless, much work remains for restoration ecologists. Invasive rats have been introduced to about 90 percent of the world’s islands. These unwelcome predators account for 40 to 60 percent of all recorded island bird and reptile extinctions.

As we continue, we’re prepared to commission an independent review to fully evaluate the project. We have every reason to expect that the project will be completely successful and the birds of the Aleutians will once again fill Rat Island with a cacophonous celebration of avian diversity.

If, after two years of careful monitoring, Rat Island proves to be once again free of the rats that have decimated the bird populations, we hope to remove the outdated moniker, and restore the island’s original Aleut name: Howadax, pronounced “How-a-tha” meaning “entry” or “welcome.” 

Please join us in welcoming back the birds of Howadax.

(Photo: Puffin. Source: Michael McBride.)

If you believe in the work we’re doing, please lend a hand.


  1. It sounds like the eagles and gulls are collateral damage. Did they die of rat poison or rat-starvation?

  2. RKB: We don’t know the answer to that question yet. We’re waiting on results from the lab. We’ll post an update when we have more info.

  3. Keep up the good work! Aarigaa!

  4. I first became interested in Alaska’s Aleutian chain in 1968 when I was issued orders to the Alaskan Air Command’s radar site at Shemya, which is also in the chain.

    Luckily, I was diverted to Sparrevohn, AFS, on the mainland which was still remote, but considerably less barren.

    I commend your efforts and add my best wishes for your continued successes.

  5. Congratulations from New Zealand on what seems to have been a successful effort in an extremely challenging location. It’s good to see that New Zealanders were involved in this project – pest eradications on islands is an area where we can make a real contribution to conservation globally.

    While the collateral damage is both sad and unfortunate, it has to put into context. Experience elsewhere has shown that the numbers of the affected species bounce back very quickly without the ecological pressures imposed by rats and other invasive animals.

  6. I’m following up on my June 2009 comment… any further information on this island and the bird deaths?

  7. Field biologists are back at Rat Island this summer, and so are the birds! This is the first year in which measurable increases in native bird populations are expected – 2009 presented the first full rat-free breeding season in more than 200 years. It’s also the fourth consecutive year in which biological monitoring has occurred on the island — this includes standardized surveys for landbirds, shorebirds, seabirds, waterfowl, game birds, birds of prey, and intertidal and vegetative communities. A second visit in late August finishes invasive rat-detection monitoring.

    The eagles and gulls that were collected on Rat Island last summer and tested for rodenticide residue all were positive. Therefore, we know the birds were exposed, and they likely died from rodenticide exposure. This was not expected and we are deeply saddened. We have commissioned an independent review of our procedures to understand what happened, and how we can prevent this sort of non-target mortality from occurring again.

    We remain cautiously optimistic that the island is free of rats, and expect a full recovery of native habitat and species assemblages.

Add a Comment