There will be a hiatus tomorrow as the photo tanks is dangerously low. But today we have photos from central California by UC Davis ecologist Susan Harrison. Her narrative and IDs are indented, and you can enlarge the photos by clicking on them.
Lake Berryessa and its Ospreys
The easternmost valley of Napa County is covered by Lake Berryessa, a reservoir that sends water to the burgeoning ‘burbs and Budweiser brewery of Solano County. The dam was built by the Army Corps in 1957 over bitter protests by the valley’s farmers, ranchers, and other residents who called their then-home an agrarian paradise. The valley’s demise was hauntingly chronicled by famous midcentury photographer Dorothea Lange.
(Oh well – giant vineyards would probably have been the valley’s modern fate, elsewise.)
Lake Berryessa:
The dam lies at a narrow gorge called Devils Gate, formed by – guess what – an earthquake fault. “If you want to find a fault, look for a dam,” once quipped late UC Davis geologist Eldridge Moores. If the Monticello Fault ever lets rip, the towns of Winters, Dixon and Davis would be inundated as shown in this simulation.
Devils Gate and Monticello Dam:
Because the canyon was too narrow for a conventional spillway, the dam has a huge vertical drain known to all as the Glory Hole, which is quite a dramatic sight when water spills into it. A Double-Crested Cormorant (Nannopterum auritum) was once filmed swimming into the Glory Hole; it emerged unscathed at the dam’s base 200 feet below!
The Glory Hole:
Lake Berryessa made national news in 1969 as the scene of a Zodiac killing, and in 2020 when California’s wildfire “Year from Hell” was epitomized by incinerating homes and habitats around the lake (no-one was hurt, thankfully).
Fire devouring Berryessa Senior Center, courtesy New York Times:
But let us speak of happier things: Osprey nesting season! The lake has at least eight Osprey (Pandion haliaetus) nests ranged along its western shore. Some nests, but not all, are on the nesting platforms meant to keep birds away from power lines.
Ospreys incubate their eggs for 36-42 days and feed their 1-4 nestlings for another 50-55 days, per AllAboutBirds. That’s parental dedication!
Nesting Osprey:
Calling to their mates who are hunting nearby:
Giving a photographer the stink-eye:
Taking a wing stretch:
Beneath at least two Osprey nests, House Finches (Haemorhous mexicanus) were nesting. Are finches doing this only because big nests are a nice shelter, or also because Ospreys scare away medium-sized predators like Cooper’s Hawks (Accipiter cooperii)? Hummingbirds and other songbirds are known to nest in the comparatively safe neighborhood of large hawks’ nests.
House Finch at Osprey nest:
Besides year-round Ospreys, Lake Berryessa supports wintering Bald Eagles (Haliaeetus leucocephalus), American White Pelicans (Pelecanus erythrorhynchos), Western Grebes (Aechmophorus occidentalis) and Clark’s Grebes (Aechmophorus clarkii). Perhaps this abundance of large fish-eating birds is some compensation for Paradise Lost?
Thank you susan. It took me a while to comment because I have been reading reference material on the dam and the lake incident. Really, really sad story, but thank you for bringing it to us. I crossed that area west to east with my family about twenty years ago going from a week visit from the East Coast to Napa Valley on to a family get together in Wheatland. Rt 128 wasa beautiful drive over the mountainand down into the eastern valley. I never thought about the damming of a wild riverand the loss of the world for established families.
Thanks for your comment, Jim. It is a very sad story. The local people sent a delegation to Congress — armed with photo albums — and persuaded them not to fund the dam, but the Army Corps and its developer friends then stuck a last-minute rider onto an appropriations bill and got their way after all. I knew one of the old-timers, George Gamble, who lost his boyhood home; he said it took him over a half-century to admit the lake was kind of pretty.
Very nice to see the area, and the ospreys in their big stick-nests. I have never been to central California, but I’d like to!
When I was a graduate student at UC Davis in the early 1970s, I routinely fished for trout along the shores of Lake Berryessa and harvested crayfish from its Putah Creek outflow. Indeed, the many fish and crayfish that I caught were a big part of my diet in those days. Thanks for bringing back great memories for me.
That’s a fun memory! People still fish the lake for bass and the outflow stretch of Putah Creek for trout, though I think the latter is catch-and-release fly fishing only. A court ruling in 1991 made the dam operators restore fall flows, and this led to the return of a salmon run.
Very fine pictures! That is interesting nesting behavior on the part of the house finches.
Beautiful photos, very interesting. I love Osprey. One of the best things about living in Lakeland, Florida (when I did) was that, because there were indeed a great many lakes, there were oodles of Osprey. When I went to a Detroit Tigers spring training game there, it was much more fun to watch the Osprey that lived near the stadium, as they caught fish in the nearby lake, than to watch the game.
you’re my kind of sports fan 🙂 🙂 🙂
Thanks for the great photos and interesting commentary. Very picturesque reservoir.
Thanks for the info on the Monticello Fault. Ospreys are great too!
Beautiful photos and an interesting commentary – much appreciated!
Very informative, and excellent photos. Thanks!
That’s a great account, thanks. When I moved to central Illinois in the 1980s, I started sailing at a local lake called Clinton Lake (built as the cooling system for a nuclear power plant of the same name). At that time there were a similar number of osprey pairs nesting around this lake built on the fork of a river. And we had wintering bald eagles occasionally. Eventually a pair of bald eagles started nesting on the lake, and they appear to have driven all the ospreys away, and I have not seen one at the lake in more than a decade. I wonder if this is a common phenomenon, that ospreys can only breed on lakes without eagles? And just to note, we have several other lakes in the area that still have breeding ospreys, sans eagles.