(2016 update: the nest is not in use this year for some unknown reason.)

I finally made it out to look at the eagle’s nest for the first time in weeks. Since it’s June, I expected the nest to be empty, and it was. While as far as I know there’s no absolute confirmation the chicks successfully fledged, the nest looks to be undamaged and empty so I think it’s likely this pair once again fledged out one or two chicks. (my intention was, as usual, to watch the nest more closely than I did. Reality amuses itself by inserting complications…)

This year the eagle’s moved the nest, so it wasn’t in the very visible and well-protected power tower location. I was able to spend some time earlier this year with the biologist who’s doing environmental monitoring of the Calaveras Dam project, and management of the species of concern in the work area and the watershed of the reservoir is a large part of his worry-list — with the bald and golden eagles being very high on that list. Any negative impact to those species could create a problem for the dam project, so they were quite sensitive to potential disruptions of the birds while they were nesting.

They invited me out to the project and we had some time to talk about the area, the eagles and how they were managing the impact of the dam project on the local environment, and they took me out and showed me the location of the nest. Because the nest is (a) on private land in a closed area, (b) and somewhat obscured from view, they were very worried about disclosing the location of the nest because it might encourage birders or others to trespass for better views. On top of that, the biologist twice tried to get a better look at the nest himself and both times flushed the adults off of it at 80 yards or further, so he felt that this pair was at high risk of being displaced off the nest if people started wandering out onto the watershed land to get a better look.

Looking at the location and situation, I agreed with him and agreed not to disclose the location until the nesting was done and the nest was empty. Now that this has happened, I’m writing this up as a bit of an info dump on this eagle pair for those interested and so I have this info for future reference.

As it turns out, the eagles moved the nest to a tree nearby the old nest; if you knew exactly where to look, you could see it from the public road. I do know a few of the local birders found it independently. I showed a few birders the location on a one-on-one basis. I had intended to set up a weekend where members of the local birding list could come and get shown the location, but I never had the time to set that up (sorry!).

The general location of the nest is 37°27’48” N 121°49’58” W. The original nest we’ve monitored is in a power tower visible from the road. Two years ago this pair moved the nest to a tree near the tower, but the limb that nest was on failed in a winter storm, and last year they moved back to the tower. This year, they moved the nest again back to the tree they nested in two years ago, on a branch about 10′ higher than the previous nest. The nest is about 40′ above ground level.

I’ve been watching this nest since 2008 (images from the Reeservoir area here). I believe the first year they nested at this location was 2007. their first successful fledge was 2009 with a single chick. They raised two chicks in 2010, 2012, and 2013, and I believe a single chick in 2011, but I was out of the loop that year.

These maps give a general view of the location. As you drive along Calaveras you’ll pass the old nest on the tower, easily visible. There’s a pasture gate at that location, and just beyond it (driving north) is a pull-out under the trees where you can park. Parking is limited, three cars, roughly, and on a couple of occasions I’ve found it occupied by cows that have let themselves out of the pastures and taken advantage of the shade…

Here I’ve set up the scope about 15′ S of the pasture gate on the side of the road.

Across the pasture is a single large oak tree. When you’re there, you can’t miss it.

Look through that tree, just to the right of the trunk and under the canopy. If you’re in the right place, it’ll frame the view to the nest.

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There is some worry that this nest is at risk at going down in a winter storm; it’s heavy, and it’s stressing the limb. I was out there one day in some significant breeze and it bounced around like crazy. We’ll see if it survives the winter and if they re-use it next year.

If you look at the location of the nest, you can see why the dam officials are worried about trespassers. It seems like an easy hike to hop over the pasture gate and wander down for a better view. In fact, just past that first tree there’s a significant bluff and a drop-off, and the nest tree is well down the slope and the nest itself about 40′ off the ground.

Given how skittish the eagles were when the biologist approached, there’s no way someone could get a better view before pushing them off the nest. Beyond the general worries about trespassing on private land and the landowners worrying about legal liability issues if someone got injured while trespassing, none of us wanted the eagles to be disturbed. The old tower nest didn’t have much risk of that, but this new one does.

Beyond the general wish to let the birds nest and fledge their chicks without harassment, the dam project had another worry; if the birds were harassed enough that they abandon this nest and relocate, if they relocated into the work area on the dam project, it could require significant mitigation or a complete stop to the dam work while they’re nesting. That could be a very expensive problem — and there is an older bald eagle nest within the work area that shows that bald eagles have in fact nested at locations that would have required a complete stop to the dam work in recent times. It’s unclear whether that nest was built by this pair before moving to the tower, or whether we’ve had multiple pairs of bald eagles nesting on Calaveras Reservoir at the same time, but there’s a history of nesting at the North end of the lake and the dam project managers wanted nothing to occur that might encourage the eagles to move back there. I can’t blame them.

That’s why we tried to be discrete about the nest location. Now that they’re done for the year and the nest is empty, it’s safe to talk about it in more detail.

When I last talked to the biologist, he’d identified this bald eagle’s nest and three golden eagle nests active in the area close to the reservoir, none in areas requiring work mitigation, fortunately. He also had identified the one unused bald eagle nest (which they got permission to teepee) and a number of unused golden eagle nests, plus many red-tailed hawk nests.

In my limited snooping up there this year, I located two red-tail nests in the area as well as strong evidence of an American Kestrel nest (the joyous sound of chicks screaming for food and a male kestrel flying out from that location). This region is a really strong area in the county for raptors of many types — second only to the Coyote Valley area — and one that isn’t as well travelled, but one that we need to make sure stays protected.