Bob Fisher releases a golden eagle with a tracking device
Bob Fisher's three years of finding, catching, and tracking San Diego County's golden eagles have made him certain of one thing:
"Eagles hate people," Fisher said. "They hate dogs. They don't mind vehicles, but as soon as a door opens and a person steps out, they take off and they don't come back for a week. If at all."
That's been a challenge to his team's mission, which is to trap the eagles, get DNA samples, and attach a three-gram tracking device. A combo of a GPS sounder, a cell phone, and a power pack, the device sends signals at either 30-second or 15-minute intervals.
What they've learned is that eagles cover huge amounts of territory, swap mates ("It's the ’70s for golden eagles," Fisher said), and get shot at a lot. They also go to Mexico a lot and avoid the L.A. basin like the plague.
The project, funded by the San Diego Association of Governments, is intended to see if the habitat set aside for the eagles is actually working and to add knowledge so that future habitat decisions will help the eagles.
"Our work on eagles has struck up a new discussion (with regulators and planners)," Fisher said. "This work may make us able to see if we've done this right."
If they don’t actually “hate people,” Fisher said eagles are shy. If they see people, they abandon nests and territory, keeping an 800-meter buffer between them. So, when people want to build a trail or a housing development — like the proposed resort at the top of Otay Lakes, Fisher said, it means the eagles will be pushed into an ever-thinning territory. Putting a few acres of mitigation land in won't help if it's surrounded by civilization, he said.
"Raptors aren't using the open space set aside for them," he said. "We're trying to get everyone to understand there's a big shadow that [eagles] are not going to use."
Since August 2014, Fisher's team has trapped and released 28 eagles, 12 male and 16 females. They've recaptured and re-released one. How they find them and catch them is a story unto itself.
"We hauled meat," Fisher said. "We've augmented the landscape with seven tons [14,000 pounds] of cow." And they've captured some funny video of animals they didn't intend to feed finding a surprise meal.
The traps, baited with meat, are set up in places people don't go — with almost all of them near the border from Otay Mountain and into East County. The eagles like rocky perches and stay west of the desert in the strip of land east of civilization.
"You look for places with no roads, no trails, no easy way in, mountainous terrain, and that's where the birds will be," Fisher said.
Eagles left the Lake Hodges area where they once hung out, with records showing them there in the 1990s, but as people moved in, the eagles headed east and south
"We can create maps of where eagles won't go," Fisher said. "We can't say where they will go, but we can tell you that they won't go within 800 meters of people and civilization...
Three of their eagles have been shot “recreationally” and one was clearly lured in to be killed near Lake Wohlford, Fisher said. The team watched the signals as the first male eagle they tagged went through three mates. The first female was shot and killed in Mexico. The second disappeared. And after he had a stable nest with the third mate, he suddenly took off to the southwest, flew down to Baja and hung around on a mountain just east of Tijuana for a week.
"We think he was shot at, maybe some neurological damage," Fisher said. "He was flying very low in an urban area — we went down on Mother's Day and we saw him on a mountain with all these people walking up it."
The female stayed at the nest waiting for a week, then took off, heading north to Perris. When the eagles fly north, they go as far as Palomar Mountain, the data show.
"She avoided Barona [reservation]. She avoided Ramona. She stays on the rocky peaks," Fisher said. "They all really like the San Diego River Gorge and the Hoskins Ranch area."
There are limitations to the data-collecting hardware, though. The device can't handle 30-second data-transmission intervals.
"We've got one sending movement data from October now; it’s never getting caught up,” said Fisher. “In 2019, I'll be able to tell you where she is today," he said. They've captured some highly ironic images, including pictures of scientists climbing up to a nest to install a nest-camera that were caught by a nest-cam that was already there.
They've also seen some terrible things, like the purposefully arranged tracking device and a handful of clipped feathers at a staged death scene — minus the carcass — where it became apparent that the eagle was killed somewhere else.
"People are shooting out there all the time," Fisher said. "It's like a carnival out there, especially on the mitigation land for the SDG&E powerlink. We've had our people sitting in a blind and people are by [an eagle] shooting."