Some Surprises at the Cosumnes Preserve, 01-06-20

Friend and fellow naturalist Roxanne and I took the non-freeway route to the Cosumnes River Preserve heading down Franklin Road.

Start Time: 7:30 am
Start Temperature: 37º F
End Time: 12:30 pm
End Temperature: 53º F
Weather: Clear and chilly
Total Hours in the field (includes travel time): 5 hours

When we got to Bruceville and Desmond Roads, we stopped to take some photos of the birds we could see in and around the rice fields and on the telephone poles. We were seeing a lot of hawks around there and managed to get photos of some of them.

Red-Tailed Hawks, Buteo jamaicensis. One was sitting in the top of a tree and the second one came up, “tagged” the sitting one, and then they both flew off.

Then we went into the preserve itself and walked along the boardwalk. We saw a lot of the usual suspects: a variety of ducks and geese and sparrows. The standouts for me were the Blue-Winged Teals, which I don’t get to see very much. We got see a handful of them, and in one photo I managed to get a Blue-Winged Teal, a Green-Winged Teal and a Cinnamon Teal all in the same frame.

A Blue-Winged Teal, Anas discors, a Cinnamon Teal, Anas cyanoptera, and a Green-Winged Teal, Anas carolinensis. All of these are males.

We also got the surprise of a Sora. We were walking toward the viewing platform at the end of the boardwalk trail and saw something in the water that ducked underneath the wooden platform. A few seconds later, the Sora stepped out on the opposite side of the platform. We only had a few more seconds before it rushed off into the tules, but it was fun to see. They’re pretty “secretive” little birds that can move quickly, so it’s sometimes hard to get photos of them.

While we were walking, we noticed several Sandhill Cranes flying overhead and heading toward the fields around Desmond Road, so when we got back to the car after finishing our walk in the boardwalk area, we drove back over to Desmond to see if could spot the cranes there.

CLICK HERE to see the entire album.

As we came up over the hump where Desmond meets the railroad tracks, I spotted a bird on one of the telephone wires… A White-Tailed Kite! From where I was sitting in the car I had to shoot through the windshield, so my pictures pretty much suck, but I think Roxanne got some good ones. We also saw several of the cranes and lots and lots of Greater White-Fronted Geese among the ducks. Closer to the road, we saw a pair of Greater Yellowlegs participating in what we thought might be courtship behavior.

It’s impossible for me to tell the males from the females in that species of bird, but it was obvious that they were a pair and that one, which we assumed was the male, was chasing and ushering the other one through the shallow water. They ran side-by-side, sometimes in a straight line and sometimes in meandering circles, and then the male would flap his wings, sometimes jumping up a little bit when he did this, and then go back to ushering the female around.

After our walk, we looked up information on the behavior and were surprised to find that there isn’t a whole lot of information on this species; it’s not studied very much. I think that’s odd for a species that seems relatively easy to locate and view. Apparently, the birds mate for life. And the Birds of North America site noted:

“Most aspects of breeding biology are poorly known. Most of the information is based on limited observations and small sample sizes... Undulating Flight Display. Unknown whether both sexes involved. Flap wings at even pace during latter half of fall and first two-thirds of rise. Flapping stops at this point and bird coasts to peak of rise on open wings. At peak, closes wings, causing brief stoop before starting to flap again. Single display can last up to 15 min; song, and occasionally other vocalizations, given throughout, although song can cease for several seconds. Courting male runs in circles around female and poses with upraised quivering wings...”

There were so many geese around making so much noise that I couldn’t hear if the Yellowlegs were vocalizing or not. I got a little bit of the display on video and took some photos. So interesting.

We could see little Killdeer among some of the other waterbirds, and seeing them reminded me of the time when I saw a mama Killdeer lay and egg right in front of me.I had seen her in a shallow green area next to the road on the Sacramento National Wildlife Refuge auto-tour route. The mama and a male were walking around in circles, and when my car approached, I thought the mom had crouched down to start her broken-wing display, but instead she popped out an egg. I was fortunate, at the time, to get a video snippet of it.

On our way home, we spotted quite a few hawks in the trees and on the telephone poles along the road. When I got home and went through my photos, it looked to me like one of the hawks might have had Avian Pox. There were what looked like warty lesions all over its feet. I thought at first the distortion was gore left over from a recent feed, but usually hawks are fastidious about cleaning their feet after eating. There’s no way of telling if the bird did have Avian Pox,of course, without testing the lesions, but distortions on the feet are typical of the disease.

“…There are two forms of the disease. The type observed in this case is called the cutaneous (dry) form. Starting as vesicles on the unfeathered skin of the feet, legs, beak, or conjunctiva, it progresses to a proliferative nodule that can become infected with secondary bacteria… [TVMDL]

The warty nodules and lesions on the bird’s feet looked like evidence of Avian Pox to me.

And we were surprised by the number of Striped Skunk roadkill we saw. I think we counted five skunks on just one stretch of road. We speculated that because it doesn’t really get cold enough here for the skunks to go into hibernation, they have to come out of their dens periodically to feed – an human garbage makes for easy pickings when the skunk’s normal prey isn’t available. ((I read somewhere, too, that skunks will leave their winter den occasionally to empty their scent glands. Don’t know if that’s true, but it’s kind of an interesting idea.))