February 17, 2023
9:30 a.m. to 12:00 p.m.
Our first off-campus trip of the semester was a visit to the Ellis Creek Water Treatment Facility in Petaluma. My students (I think 18 of them were in attendance) met me in the parking lot at 9:30 a.m., and spent about 2.5 hours walking the trails around the finishing ponds (total distance traveled: 2.6 km). The weather was clear and cool (but not cold). By the time we’d done about half of our hike, it was too warm for the fleece jacket I’d put on earlier in the day.
We had an amazing day, with a total of 47 species across all observers (although I didn’t personally see all of them; I saw or heard 43 species). Below are my own observations for the day.
Before we’d started our hike, we found a few birds near the parking lot: a vocal Song Sparrow in a small tree, and a pair of California Scrub-jays who were only in view for a short time as they moved through the trees to the northwest of the parking lot. I also heard an American Crow, but never spotted the bird. Rather than climbing the slight rise that would take us to the north-most pond from the parking lot, we opted instead for the drier route along the trail and then south along the side of the western pond.
There was a good diversity of birds in the pond: Green-winged Teal, Mallard, a few Black-necked Stilt, Canada Goose, Northern Shoveler and American Coot. We heard a Killdeer (although I didn’t get my eyes on one until later in the day). Savannah Sparrow and American Pipit were foraging on the grassy verge next to the trail, and I saw a lone White-crowned Sparrow (more would be seen later).
I was happy to witness some interesting mating behavior – a pair of Green-winged Teal who copulated in the pond just a few feet away from where we were watching. They began with a short bout of head bobbing, and then the male mounted the female. The copulation lasted about 15 seconds, and then the pair swam off to the north.
Another early highlight of the day was a flock of a couple dozen Least Sandpipers. They started out foraging in the mud in some short vegetation, then flushed and flew around the pond briefly before settling even closer to our party than they had been before. Very cute.
We continued along the trail, and at the next pond I saw Bufflehead, Ruddy Duck, and Gadwall. At least one Cinnamon Teal was present (although, sadly, I never got a good look). Several Mute Swan were present (more than I recall seeing here in the past), and an adult Black-crowned Night-heron was perched about half way up some reeds, sitting very still but pretty obvious due to its coloration. We later saw a couple more night herons, including at least one juvenile. There were also, unsurprisingly, Marsh Wrens singing from the bulrushes, and I did manage to get a few glimpses of them as they flitted around the edge of the pond. A Great-tailed Grackle flew overhead briefly, and I caught a glimpse of a Red-winged Blackbird. A Black Phoebe hunted over the pond, and Audubon’s Warblers were seen here and there. In the upland area where large trees are growing, Turkey Vultures were perched in a bare tree, while Tree Swallows flitted in and out of nest boxes. (There were loads of swallow hunting over the ponds, too – surely violet-green in addition to tree, but I never got a good enough look at a v-g to put it on my list for the day. There are also barn owl boxes on site, although we didn’t see any of the owls.
When we reached the southernmost trail, I was starting to tire and my hip was aching a bit, and I was prepared to turn the group back toward the parking lot, assuming that most of my students were probably ready to be done. But then the folks in the lead continued on the south trail, so we all followed. So glad we did, as this is where we had what I found to be the most spectacular sighting of the day. I’d noticed a great egret perched in the rushes when one of my students called out that he’d seen an American Bittern . . . no, TWO bitterns. They were at the far end of the pond from where we were standing, but one of them was visible (although fuzzy even through the lens of my camera). I managed to snap a couple of lackluster photos when the bird flushes, and flew in our direction! It ended up landing in some rushes much closer to where we were standing, and we were able to view the bird for a couple of minutes before it disappeared deeper into the bulrushes. MAGNIFICENT! None of my photos are particularly good, but considering that this is only the second time in my life I’ve seen this species, I’m not too disappointed. I was also super excited for my students to see such a great and somewhat difficult to find bird on our very first venture off campus!
Before we moved on from this spot, an Anna’s Hummingbird perched cooperatively nearby, and then we decided to keep going. Originally, I’d thought to suggest that we backtrack from here, and take the shortest route back to the parking lot, but knowing that there was a bittern in the rushes nearby gave us some incentive to take the slightly longer route that would take us near where we’d last seen the bird. So, we followed the path around, finding several Canada Goose foraging on the grass, along with a pair of Cackling Goose. It was a great sighting, and very easy to see the differences between the species when they’re side-by-side like this. A couple of Killdeer were also foraging around a shallow pool. A flock of a dozen or so White-crowned Sparrows were foraging along the side of the path, and as we were slowly approaching – trying to get close without making them flush – we had another amazing moment. One of the bitterns flew up out of the reeds and soared right past us, very close, heading south. Again, I didn’t get any good photos, but I did get it in focus for a bit through my camera at one point, giving me a great, clear view of this gorgeous bird. It was really special to get such great looks, and I think most of us were pretty excited about it. I joked that this might be the “best” bird we see all semester (but chances are that it’s true, at least for me). It also makes me want to go back to Ellis Creek on my own and spend a bit more time trying to get some decent photos. But for now, I am very grateful for the amazing sighting I had on this day.
When we continued on, one of the night-herons flew by (also impressive), and as we approached the little strip of upland habitat, we discovered that a Red-shouldered Hawk was perched right out in the open on a bare tree. (To be honest, I’d been surprised that we hadn’t seen one earlier in the day). The bird stayed in the spot while we approached, and then walked all the way around the upland area, allow us to get good looks from multiple directions. These really are such pretty birds! Nearby, on one of the interior ponds, I spotted a Pied-billed Grebe near a pair of Gadwall. I also snapped a photo of a Fox Sparrow (although didn’t realize what it was until I looked at the photos back at home). There was a Song Sparrow behaving very much like a marsh wren (holding its tail at an angle and everything). But the photos are clear – it is a sparrow. A Common Yellowthroat was also bopping around in a bush very near where we were standing. A single, male Western Bluebird sped past us – I just had a glimpse, but fortunately that is an unmistakable bird.
Now heading back to the cars (for real this time haha), we passed back by the first pond to find a Snowy Egret hanging out with some ducks and geese, and we had a few more great views of some of the waterfowl. Back at the parking lot, as we were packing up, I saw my final bird of the day – an adorable little Ruby-crowned Kinglet perched in a tree very near my car.
This was a great morning. We stayed longer than I’d anticipated and everyone seemed to enjoy themselves. We definitely saw a lot of great birds (although no other vertebrates, although someone did hear a chorus frog). A great start to wildlife viewing for the semester!
Species List
Song Sparrow (Melospiza melodia), California Scrub-jay (Aphelocoma californica), American Crow* (Corvus brachyrhynchos), Turkey Vulture (Cathartes aura), Green-winged Teal (Anas carolinensis), Mallard (Anas platyrhynchos), Black-necked Stilt (Himantopus mexicanus), Killdeer (Charadrius vociferus), Savannah Sparrow (Passerculus sandwichensis), Canada Goose (Branta canadensis), Northern Shoveler (Spatula clypeata), American Coot (Fulica americana), Least Sandpiper (Calidris minutilla), American Pipit (Anthus rubescens), White-crowned Sparrow (Zonotrichia leucophrys), Bufflehead (Bucephala albeola), Ruddy Duck (Oxyura jamaicensis), Black-crowned Night Heron (Nycticorax nycticorax), Mute Swan (Cygnus olor), Canvasback (Aythya valisineria), Common Goldeneye (Bucephala clangula), Cinnamon Teal (Anas cyanoptera), Tree Swallow (Tachycineta bicolor), Gadwall (Mareca strepera), Western Bluebird (Sialia mexicana), Marsh Wren (Cistothorus palustris), Great-tailed Grackle (Quiscalus mexicanus), Red-winged Blackbird (Agelaius phoeniceus), Audubon’s yellow-rumped warbler (Setophaga auduboni), Black Phoebe (Sayornis nigricans), American Bushtit (Psaltriparus minimus), Great Egret (Ardea alba), American Bittern (Botaurus lentiginosus), Anna’s Hummingbird (Calypte anna), Cackling Goose (Branta hutchinsii), Ring-billed Gull? (Larus delawarensis), Pied-billed Grebe (Podilymbus podiceps), Red-shouldered Hawk (Buteo lineatus), House Finch (Haemorhous mexicanus), Fox Sparrow (Passerella iliaca), Common Yellowthroat (Geothlypis trichas), Snowy Egret (Egretta thula), Ruby-crowned Kinglet (Regulus calendula)
*Heard only
It also seems worth mentioning that there were a number of species I expected to see that were absent, including Great Blue Heron, White Pelican, Lesser Goldfinch, American Goldfinch
Let me know what you think!