Dead eiders like clockwork

26 10 2010

Great Island on Cape Cod in Massachusetts: site of the eider die-off (photo: D. Jordan)

Right on schedule, eiders have begun turning up dead on Cape Cod once again. The last reported die-off occurred at exactly this time last year,and the profile of birds involved is similar once again: mainly males with occasional adult females. While determining the cause of these die-offs has been a long, often arduous process, this year we are better positioned than ever to make progress. The reasons for our optimism are mainly personnel based: we have a new “eider intern” on the ground on the Cape. Ashley Gorr will be surveying the Great Island area, which is generally the epicenter of these events, and she will be collecting wings from some of the birds for examination by experts. Getting an accurate age on male eiders is notoriously difficult, but details of wing plumage can assist in the process. Ashley will also collect data on live birds present in the area so that we will have a sense of what proportion of the local eider population is apparently involved in the die-off.

In addition to Ashley, we have a new SEANET volunteer, Dick Jordan, who has taken on Great Island’s western shore as his SEANET route. This is something we have longed for for many years, so we offer our profuse thanks to Dick. On his beach walk on October 13 (an epic seven hour tour!) Dick recorded 18 dead or dying eider, a Herring Gull, and a Ring-billed Gull. This introduction to SEANET surveys was quite a grueling one, and we hope that Dick will enjoy more leisurely walks once the die-off abates. He even made a valiant attempt to transport a sick female eider to a wildlife rehabilitation center, hiking an hour out to his car with the bird. Unfortunately, she died upon reaching the parking lot. A second bird Dick tried to transport died en route to the rehab center. Birds involved in these events have notoriously low survival rates; in fact, SEANET does not know of a single survivor over the many years these die-offs have been occurring.

A profoundly weak female eider. She died hours later. (photo: D. Jordan)

Working off of a tip provided by Dick, Randy Mickley of the USDA headed out to Great Island on ATV to collect numerous sick eiders. He captured 13 seriously ill birds which were then humanely euthanized and will be examined by veterinary pathologists at two institutions in an attempt to get closer to a definitive answer on these events. Special thanks also goes to Chris Dwyer of the US Fish and Wildlife Service who has been exceedingly supportive of this investigation all along and has provided coordination and assistance at every turn. Finally, thank you to Bob Cook of the National Park Service, who granted Randy ATV access to the site so he could collect the birds just as night was falling. It all converged to create a very dramatic picture of collaborative science in action.

We will keep you posted on the results of the autopsies of the 13 birds, and thank you to all parties involved here–your cooperative spirit is affording us our best chance yet of building on previous years’ work and getting to the bottom of this!



4 responses

31 10 2010

We just spent a week camping on Cape Cod. On Friday 29 October we took a walk to Jeremy Point and noticed several dead Eiders. I did not know about this problem then, so I was intrigued. At the farthest tip there were three still alive but in a bad way, two birds, a male and a female managed to hobble away from us but a third (male) was flapping about helplessly. I approached it thinking it might be tangled up in fishing line or net and that I could help it. I saw that this was not the case and could examine it carefully thinking then that it might have been wounded by a hunter. It looked to me perfectly healthy and well fed with no apparent wounds and the way it was acting seemed to indicate some sort of poisoning. I thought of bring it to a shelter to get some help but I did not know where and did not think it could survive the trip. The only thing I could do was to cover it with a washed-up plastic crate so that it would not be bothered by the numerous scavengers (Turkey vultures) during its last moments. A sad story, it brought tears to our eyes, such a beautiful bird, such a beautiful setting, I could not help thinking that we humans were somewhat responsible for its death…
I then noticed that that several carcasses had orange tags through the bills and that really aroused my curiosity so I stopped a the National Seashore Visitor centre and the helpful staff told me about this problem. Wish we could help but we are a little far to volunteer.
David and Carmen from Montreal, Canada

18 11 2010
Superstar Seanetter stellar citizen scientist « SEANET Blog

[…] found a couple dead Common Eiders (a typical find this time of year on the Cape), as well as a dead Thick-billed Murre. He also found an additional […]

18 12 2010 » Winter Walk in Wellfleet

[…] and they turn to crabs and shoreside berries. (update: it appears that source is unreliable and the mystery of the eider die-off continues) I was surprised to find three dead porpoises —  big […]

4 01 2011
Goings on in Wellfleet, MA « SEANET Blog

[…] as the tide of dead eiders began to ebb, Seanetter Dick Jordan on Great Island in Massachusetts had new discoveries to make […]

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