By Idaho Fish and Game Wildlife Diversity Biologist, Joel Sauder
Many wildlife species need large landscapes to survive and thrive. Elk often summer at higher elevations and move 10-50 miles to find winter ranges at lower elevations. Songbirds that summer in Idaho can winter in the Southwest US, Mexico, or even further abroad. Wildlife make these movements without compass or GPS, just using the instincts they were born with. While we know these facts in our heads, we get jaded to them over time, because that is just the nature of our busy lives. But every once in while we get an opportunity to see them again for the first time, and we should be amazed.
Late this winter I got a call from Steve Lewis, a USFWS researcher based in Alaska. A transmitter he had deployed on a golden eagle had stopped moving outside of Grangeville and he was hoping I could recover it for him. Besides salvaging a valuable piece of equipment, knowing if the bird perished or if the transmitter was shed was important information. The most recent location transmitted showed it was on private land out towards Pine Bar. After making contact with the land owner, who not only gave permission to recover the transmitter but was excited to assist in the recovery effort, we ATV’ed as close as we could to the location and starting hiking. In the end, it turned out to be a pretty straightforward affair. The transmitter was right at the last reported location, still attached to the golden eagle, which looked like it just fell out of sky, with no clear cause of death.
This is where the story gets interesting. Back in the office, Steve sent me the data that had come from this bird. It turns out it fledged in 2017 in Denali National Park, where it had been caught by Steve. A solar powered transmitter mounted on its back via a lightweight harness. Then over two and a half years, the transmitter logged over 61,000 locations! In 2017 it left Denali National Park and wandered south, eventually ending up in southeast British Columbia. The summer of 2018 found it back in central Alaska, but come fall it made its way south again, this time ending up in Eastern Washington. In the summer of 2019, it ventured even further north, living on the North Slope, getting right to the edge of the Arctic Ocean. Then, over roughly a 4 month period, the eagle beelines south over 3000 miles, ending up in Idaho!
We ended up sending the carcass to a lab for testing in hopes of learning the cause of death. Turns out the most likely cause was lead poisoning. There is no way to know when and where the eagle got the lead, but bullet fragments left in gut piles from harvested wildlife are a common source. This is a gloomy reminder that our local actions can have regional or global impacts.
Over its short 2.5 year life (eagles in the wild are known to live 15+ years), the bird flew in excess of 9,000 miles, spread across four states and two provinces. It is easy to assume the wildlife we see around us is just the local red tail hawk or a “town” deer. We have golden eagles that breed in Idaho, and for anyone that saw that bird it would be easy to assume it was a local bird. However, those assumptions are not always accurate. Wildlife often has needs that span scales we forget to appreciate and accommodate. And if we get a chance to step back and recognize this anew it is well worth it.
For further information about this eagle or the golden eagle research occurring in Alaska, please contact Steve Lewis at firstname.lastname@example.org