Caddisfly Larvae and the Nemesis Bird, 05-25-21

I got up around 6:00 this morning and headed over to the Gristmill Recreation Area on the American River for a walk. I hadn’t been there for a while, so I missed the fledging of the Red-Shouldered Hawk babies there. It was about 57° when I arrived, but the sun came up fast and hot.

I walked the most-used trail and then ventured out a little bit onto the river’s edge where there was some still, shallow water.

On the trail I could see some birds in and around the bird boxes including House Wrens and Tree Swallows. The wrens fill their box full of twigs, so there’s stuff poking out through the entrance hole — which makes it pretty easy to figure out who’s in there.

While I was taking photos of them, a pair of California Quails ventured out from a tangle of wild blackberry vines and scuttled across the trail. Just one male and a female; no harem and no babies.

CLICK HERE for the full album of photos.

As I walked along, I could hear the chattering sound (called a “rattle call”) of Belted Kingfishers in the trees along the riverside. They’re like my “nemesis birds”: I can hear them a lot, but seldom get to get any photos of them because they’re shy and move so quickly. I was lucky today, though, two females landed on the same branch, and I was able to get some photos and some video snippets of them.

A female Belted Kingfisher, Megaceryle alcyon

Kingfishers excavate and live in burrows in the banks of the river. I think they’re nesting cavity may have been below where the females were sitting, but I’m not sure.

I was taking photos of one of the Kingfishers when a bird group went past me on the trail. A few second later, one of the men in the group came back to me and asked me my name. I told him it was “Mary”… and then gave him a closer look. “Gene?!”

“Yes!” he said. It was Gene Trapp, and his wife Jo Ellen Ryan was with him along with a few other people. Gene and Jo Ellen doing bird counts and maintain the pollinator garden at the West Davis Pond site in Davis. (They have a house within walking distance of the park.) I’d first met them when I worked at Tuleyome. Gene always supported my desire to be a naturalist, and attended the lectures I gave on plant galls. It was so nice to see them!

They walked me over to where their small birding group was and introduced the leader (who was hauling around a birding scope) as Jeri Langham. Jeri literally walks the trail almost every day. He’s the one who’s set up and monitors all the bird boxes there.

Jeri let us know that the little Western Screech Owl I’d seen regularly in one of the nest boxes had actually had two babies in there this year! Neither the mom nor the babies was outlooking around this morning, but it was fun to think of them hunkered down all safe in their little box-home.

He also pointed out another box in which, he said, had been occupied by Barn Owls. They laid eggs in the box over several days, but on one day, while they were away from the box, a Merganser had flown in and laid several eggs of her own in there. Brood parasitism (egg-dumping) occurs frequently for these ducks. When the owls found the duck eggs, however, they abandoned the nest… Sad-face emoji.

I gave him my card, and asked him to contact me next time he was putting a group together. After meeting everyone, and giving Gene and Jo Ellen a hug — which I wouldn’t have been able to do last year — I excused myself to continue my walk.

Along the river, we could see a mama Common Merganser duck teaching her red-headed babies how to dive and scan for fish in the water. Later, Jo Ellen got a photo of them resting and drying off. The merganser babies are sooooo cute!

Common Merganser, Mergus merganser, mama and her babies resting after their swim.PHOTO BY JO ELLEN RYAN.

I also saw a Great Blue Heron on the shore trying to figure out how to tackle and eat a fish that was nearly as big as it was. I think it might have stolen the fish from a stringer owned by the fishermen further up the shore. I don’t think it was an older cast-off because it hadn’t attracted any vultures, and it looked too large for someone to have just thrown away. I watched the bird struggle with it for several minutes before it gave up.

Great Blue Heron, Ardea herodias, with a fish it couldn’t figure out how to eat.

In the shallows by the river’s edge, I came across several killdeer. I watched out for their nests (which they create in the stones) but didn’t see any; no babies either.

In the insect realm I found Boxelder Bugs, a Black Dancer Caddisfly, honeybees, a few jumping spiders (one hauling a fly that was as big as he was), and a colorful Case-Bearing Leaf Beetle, among others. In the shallow water, scooting and hopping through the mud and silt, I found several Big-Eyed Toad Bugs. Seriously. That’s what they’re called. They have big bulging eyes and a heavy “collar”, and they hop all over the place when disturbed. Never noticed them before.

The find of the day for me, though, was seeing and getting some close-up shots of caddisfly larvae. I was almost done with my walk when I found them, so I wasn’t able to spend as much time with them as I’d have liked to. I was tired, and it was it already getting “too warm” for me. I’ll go back some other morning, first thing, when I’m feeling stronger and it’s cooler outside. Anyway, I picked up a few of the little buggers and took some photos and video snippets of them.

Caddisflies spend their larval stage underwater, then emerge (like dragonflies do) from the water as terrestrial adults. The most common adult Caddisfly was see around here is the Black Dancer Caddisfly, Mystacides sepulchralis. I’m not sure if the larvae I saw were Black Dancers or some other species, but I think they were from the suborder Integripalpia (the “portable case makers”). They protect their soft bodies by covering them with a case made of bits of gravel, sand, tiny sticks… whatever they can find. After the adults emerge, they only live for a week or two, just long enough to find a mate and reproduce.

“…Case-building caddisfly larvae use [their] silk to construct various portable shelters. They protect soft their abdomen from predators, and abrasion from coarse particles drifting in stream. If disturbed, larva can retreat into the case, which is constantly being repaired when damaged, or rebuilt as the larva grows…”

One of them that I picked up had a case made of sand crystals and tiny sticks; so interesting. While I was taking photos of it, the birding group caught up with me and asked what I was doing — so I gave them the 5-minute elevator speech about caddisfly larvae. I showed them some of the larvae walking through the water, and also pointed out the trails they’d left in the silt on nearby rocks. They were all very excited about it and thanked me fore teaching them something new.

I also found a few galls on this trip including the oak apples, and a couple of willow galls: stem galls created by sawflies, and rose gall created by midges. Lots of different things to see today…