Saturday, January 16, 2021

An Open Slope


In the winter I often visit a big, open, grassy slope off of Highway 49, that drops down to the North Yuba River. It is one of my favorite places to observe nature. I never know what I might see! The open field attracts a variety of birds, insects, and a few mule deer. It's easier for predators to see prey here, and vice versa. Deer forage on the grasses. Raptors come here to hunt for rodents, reptiles, and other birds. Birds visit to eat seeds and insects. Insects enjoy the warmer temperatures of the sunny slope. I find it really rewarding to observe an area repeatedly. There's always something new happening, patterns emerge, and the "pulse" of the area becomes familiar. 

Non-biting Midges - Chironomidae Family

This week the Non-biting Midges were back!  I see them every year in the winter!  They looked like fountain spray on the tops of the scattered pine trees!  The shape changed continually while I watched for 10 minutes!  Such backlit beauty! 

Most midges are active from Spring through Fall, but some orders fly in the winter. Adult midges are known for their large mating swarms. Often, these cloud-like swarms congregate just above some tall object such as a bush, tree, hilltop, or over a pool, stream, or lake. How lucky I was to watch this incredible spectacle! 

Non-biting Midges - Chironomidae Family

Midges are often mistaken for mosquitoes due to their similar size and body shape. They lay their eggs in shallow waters. The eggs sink to the bottom. In a few days the larvae hatch out of the eggs and burrow into mud, or construct a small tube in which they live, feed and develop. The aquatic larvae feed on detritus in the water and are a great source of food for fish and aquatic insects. After 2-7 weeks, the larvae turn into pupae. The pupae then swim to the surface and the adults emerge from their pupal exuviae (cast off skin). Adults do not feed and spend their short, 3-5 day lives mating! 

So then I wondered what eats midges?  It seems like they'd be a good find for some hungry bird in the winter. It turns out American Dippers eat their larvae underwater.  What about in the air?  Several times in the past week I spent time watching the midges, but never saw a bird eat them. Of the birds that are here now in winter, I would guess that a Black Phoebe might eat them as they are insectivores.  I need to keep watching!

American Kestrel (male, juvenile) - Falco sparverius

Two days ago I was thrilled to see a juvenile male American Kestrel perched in the top of one of the pines on this open slope!  WOW!!!  I have never seen a Kestrel in our neighborhood before!  What a beautifully colored little falcon!  They are the smallest falcon in North America, measuring 9" in length, with a wingspan of 22", and a weight of 4.1oz.  Their diet consists primarily of insects and small rodents such as:  grasshoppers, beetles, dragonflies, scorpions, spiders, butterflies, moths, voles, mice, shrews, bats, snakes, lizards, frogs, and small songbirds!  Right now there aren't many insects around, so it was probably hunting for rodents in the field.

American Kestrel (male, juvenile) and Non-biting Midges
 Falco sparverius - Chironomidae Family

American Kestrels prefer to hunt in wide open, grassy fields.  Locally, open fields aren't that common, and are usually man made.  The majority of the land is covered in a dense, mixed-conifer forest. Typically, American Kestrels are found in lower elevations in the winter.  The currently mild winter may be the reason why this American Kestrel arrived in our area.  This one stayed around for about four days.  It was so fun to watch, and didn't seem to mind my presence.  I was, however, careful to not over-extend my welcome and limited my observation times to around 15 minutes.  I didn't want to interrupt his search for food. 
Red-tailed Hawk (adult) - Buteo jamaicensis

Two winters ago, an adult Red-tailed Hawk frequented this open slope.  I would often see it perched in the top of a pine tree, searching the slope for prey.  Red-tails are medium sized hawks, measuring 19" in length, with a wingspan of 49", and a weight of 2.4 lb. They are one of the mostly commonly seen raptors in North America, and are found from coast to coast in the U.S. and as far south as Venezuela.  If the winter is snow-free, they will live year-round in our neighborhood.  They like to perch in trees, or posts on the edges of clearings or meadows, and watch for prey. Ground squirrels, gophers, rabbits, mice, snakes, lizards, kestrels, and meadowlarks are their main prey. They use the perch-and-wait method of hunting. Once prey is sighted they will drop from their perch, flap-and-glide downward, thrust their legs forward when about 3 m from prey, and grab prey with feet. I'm so glad a Red-tailed Hawk didn't show up while the American Kestrel was here, even though two of them have been in the area the past few weeks!

Black Phoebe (adult) - Western Bluebird (male)
Sayornis nigricans - Sialia mexicana

Lately, every time I visit this open slope, I see a single Black Phoebe perched on its edge.  Black Phoebes are typically non-social and solitary, except during breeding season.  They are flycatchers, and feed by flying out from a perch and catching flying insects, or "hawking".  Their diet consists of variety of insects, spiders, small fish, as well as fruits and berries in winter.  Midges aren't listed in their diet of insects, but perhaps they do eat them!  They prefer to live near water.  They are year-round residents in our neighborhood, and do not migrate. 

In the past years, as well as a month or so ago, I've seen Western Bluebirds feeding in this open slope. In the winter they stay in small flocks. In the summer, Western Bluebirds are primarily insectivores. In winter they eat fruits and berries, such as juniper, poison oak, wild grapes, and elderberry. They also particularly love to eat mistletoe berries, and will sometimes sleep overnight in a clump of mistletoe to defend their find! They like to live on the edge of open areas, such as meadows or burned areas. They are short-distance migrants, and generally move down slope in winter. Males have brilliant plumage, and females are dully colored in comparison. They are SO beautiful with their brilliant powder-blue feathers!

Columbian Black-tailed deer (buck) - Odocoileus hemionus columbianus

I've seen several deer off the highway, by this open slope, in winter.  Usually when it's raining or drizzling.  Apparently, if rain is warm and not too heavy, deer will remain active. When a rainstorm is heavy and cold, they tend to seek shelter and bed down. But there are always exceptions! Nature is not that predictable. Rainy weather also has some advantages. Rain makes dry leaves limp and quieter to walk on, increasing the deer's ability to be stealthy. The increased moisture in the air also increases their sense of smell and hearing. A few years ago, this young buck, bounded across the damp field when it saw me. The size of its antlers indicated its young age. Male mule deer shed their antlers between January and March. Antler regrowth begins in April and extends through August. 

Columbian Black-tailed deer (does) - Odocoileus hemionus columbianus

I luckily saw this female deer and her two offspring several times this past month, just across the highway from the open slope!  The young are twins and almost full grown.  They will stay with their mother until next Spring or longer. Female deer often travel, throughout their life, in groups of females that are related through maternal descent. Right now, most females are traveling together in small groups, foraging on grasses and shrubs.  I've never seen this group in the field.  I does seem that they would be super obvious to a Mountain Lion out on that open slope!

Hygroscopic Earthstar - Insect-egg Slime
Astraeus hygrometricus - Leocarpus fragilis

I found these two interesting organisms on the open slope this week! The Earthstar was in among the dried grasses, and is a type of puffball mushroom. Spores are emitted through the hole in the central sphere. The Insect-egg Slime was growing on pine needles in the shade of a tree. I've only seen it once before, in a damp shady forest. iNaturalist.org identified it for me! It is not a fungus, or mold, it is a slime mold. The following information from https://herbarium.usu.edu/fun-with-fungi/slime-molds explains the difference.

"Defining Fungi and Slime

Slime molds may be slimy, but they are not molds. Molds are fungi. A century ago, fungi, were defined by what they did not have, or did not do:

- They did not move, like animals.
- They did not have the green pigment chlorophyll
- They were not as small as bacteria.

Today, organisms in the Kingdom Fungi are defined by:

- having chitin in their cell walls. 
- not being able to move during any stage of their life cycle
 - lacking chlorophyll
- being larger than bacteria.

Alive and Durable

Slime molds move, and lack chitin in their cell walls. They are now classified as belonging to the Kingdom Protista (Protoctista). 

Their ingestion of food is one reason slime molds are not considered to be fungi. Fungi produce enzymes that break down organic matter into chemicals that are absorbed through their cell walls, not ingested."

Common Goldeneyes on the surface, and underwater
Bucephala clangula

On the river below the open slope, I've often seen groups of Common Goldeneyes feeding in the winter. In California, Common Goldeneyes are the only ducks that regularly spend the winter on rivers and lakes above the foothills of the western Sierra. They are diving ducks and eat fish, aquatic vertebrates, seeds, and tubers. When diving, they keep their wings pressed to their sides underwater, and swim with their webbed feet! They will spend the rest of the winter here. In the spring they will leave for their northern breeding grounds in Alaska and Canada. The open slope is a great vantage point to watch them swim underwater!

Upper Sardine Lake - 1/10/21

Lakes Basin Update

Last week we hiked up to Upper Sardine Lake from Highway 49.  This time there was less snow on the ground, but we could see more snow at the higher elevations. It was a gray, overcast day, just great for photographing white snow!  It was lovely as always to be back up there!  


More Damp Earth Art!

Since the local rainfall total at this point is way below our normal amount, I am once again sending out a "Call for Art" in celebration of rain. My intention is to focus on the need for rain, and through collective positive energy invoke rain to fall. It is just a wish, a thought, and a hope. If you would like to submit some art, or writing, or a photo please email me at northyubanaturalist@gmail.com. Check out what's already been submitted at dampearthart.blogspot.com

You can view what was submitted last year at dampearth.blogspot.com.
I will be posting new art weekly. Check it out and pray for rain!


How is Project FeederWatch going?

How deep is the snow at Yuba Pass?

What's happening at the local ponds?

Check back next week for the answers to these questions and more!

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