Tuesday, May 2, 2017

Desert Bighorn Sheep at Agua Caliente County Park

Agua Caliente County Park is very isolated in The Anza-Borrego Desert. There's no direct way to it. You have to go over the mountains and then either north or south on the "Great Southern Overland Stage Route of 1849." That road name itself should evoke the Old West and the wildness of the area.

From San Diego you have to travel east 90 miles on I-15 to Ocotillo and then north for 30 miles (most miles, least time--2 hours). Or, you can travel 63 miles to the mountain tourist town of Julian and then down 12 miles to Scissors Crossing and south another 22 miles (20 miles shorter, 7 minutes longer (unless Julian is at its usually crowded and clogged weekend self--when it can take 20 minutes to get through the 1/2 mile long Main Street, which is also State Route 78 and 79)).

From Escondido, in the North County, it is 80-90 miles, and about 1 hour and 45 minutes. The shorter route goes through Julian, the less-trafficked route through Warner Springs.

Agua Caliente features a campground, hot springs and pools, and hiking trails. The birding is great in spring. That's when birds migrating out of Mexico at night find themselves at dawn over the great American Southwest deserts. Then the trees and water in this campground become a welcoming oasis in the dry surrounding lands.

As Marlene and I were about to depart from our lunch stop here, she spotted some movement on the hillside above the park entrance--our first views of Desert Bighorn Sheep (Ovis canadensis nelsonii)! Actually, the Bighorn Sheep here are quite distinctive and were formerly considered a separate subspecies called the Peninsular Bighorn Sheep (O.c. cremnobates).

Desert Bighorn Sheep at Agua Caliente County Park

Desert Bighorn Sheep at Agua Caliente County Park

Desert Bighorn Sheep at Agua Caliente County Park

Unlike other Bighorn Sheep, this variety is perfectly adapted to the desert. Apparently, their body temperature can safely fluctuate several degrees. This allows them to handle the cold nights and hot days of the desert during winter and summer. They are very adept at obtaining rainwater on rocks, and getting moisture from the plants they eat, so much so that they may not visit permanent water sources for weeks at a time.

Desert Bighorn Sheep at Agua Caliente County Park

Desert Bighorn Sheep at Agua Caliente County Park

Desert Bighorn Sheep at Agua Caliente County Park

Colored pencil drawing Bighorn Sheep by Greg Gillson

Monday, April 24, 2017

The bizarre song of the Yellow-breasted Chat

It was clear and sunny, but surprisingly chilly here at sunrise. Though it would make its way into the mid '70's in a couple of hours, it was unexpectedly 30 degrees cooler than that right now in this river valley. Birds were singing and calling and flying about actively this early April morning near Escondido. While my attention flitted from bird to bird, a distant birdsong was trying to interject itself into my consciousness.

"chuck-chuck-chuck-chuck."

No, not rolling enough for Cactus Wren. It's not a Mockingbird, either. No, no, it's completely wrong for Roadrunner. I know that call, but I just can't place it.

A few minutes later the "chuck-chuck-chuck" call joined a whistled "whoit, whoit" and then a crow-like "caw, caw, caw" and some cackling. Oh! Yellow-breasted Chat. Of course!

Yellow-breasted Chat
Yellow-breasted Chat in full-throated song. Escondido, California. April 5, 2017. Greg Gillson.
Except when singing so brazenly, the chat is reclusive, shy, wary. But in spring and summer--even at night--it makes a joyful noise in the densest riparian thickets.

This chat was a week earlier than the typical first arrival of the species locally. When he has more male competition, and the attention of females when they arrive in a week or so, then watch out. The varied song now will take on a fevered pitch. The flight display song the male gives to the female is both amazing and bizarre. The male sings its varied song, but rises slowly in circles in the air. His wingbeats are mechanically exaggerated, his head lifted in song, his long tail pumping wildly, and his feet dangling down, trailing below as if forgotten. When he reaches a pinnacle--hovering, down he glides--ever so slowly--as his singing and his flight slowly come to an end.

Yellow-breasted Chat

Yellow-breasted Chat

Yellow-breasted Chat

Yellow-breasted Chat in colored pencil. Greg Gillson.
Yellow-breasted Chat in colored pencil. Greg Gillson.

Thursday, April 20, 2017

Eucalyptus in San Diego

Eucalyptus, also called gum trees--the tallest flowering plants in the world, are one of the more obvious and widespread imported and feral trees throughout central and southern California. However, they vary so much it is hard to describe exactly what it is that makes a tree identifiable as a Eucalyptus to the casual observer.

There are over 700 species of Eucalyptus. They are native to the Australian region. Over 250 species have been cultivated in California. [Read "How the Eucalyptus Came to California" by Teisha Rowland in the Santa Barbara Independent newspaper of January 15, 2011.]

In this post I describe marked differences in the bark, leaves, and flowers of several varieties seen in the San Diego area, which I haven't even identified to species level! I've done some research on Eucalyptus, which provides additional details beyond my observations.

The tree shape, more than anything identifies the Eucalyptus at a distance. The tree shape is tall and generally thin; it doesn't have large spreading branches. All have leaves in sparse round clusters at the tops of the tree, most have some thin clumps of leaves on smaller branches hugging the trunk. The leaves and clusters hang down, slightly drooping. All forms are rather unsymmetrical, being lopsided and crooked, and there are usually long bare trunk and branch sections amid tree. The general appearance of most Eucalyptus is tall and "trunky," open, with round bubble-shaped crowns.

Leaves are generally blue-green and sickle-shaped--long, thin, curved. Some tend more toward green, blue, or gray. These are evergreen, with a constant supply of new leaves, though more leaves are shed in dry times. Leaves contain oil that have disinfectant qualities--toxic in large quantities. The oil can also be used as a solvent and insect repellant. You may find the oil in cough drops and the leaves used in floral displays. The koala is one native Australian mammal that can eat the leaves. Leaf-bearing stems are white, gray, light brown in most species, reddish in some.

Little fluffy flowers vary from reddish to pink to yellow to white. They grow in a capsule without flower petals, The capsules and seeds tend to be messy. Flowers are full of nectar and attract insects and birds (especially hummingbirds in the Americas, which are not found in Australia).

The very thin sheet-like bark on most varieties sheds annually to some degree, revealing a smooth white, pale gray, or golden-brown trunk. But not all. One common form has hard dark brown bark with deep furrowed ridges and doesn't shed ("ironbark"). Others have bark in strips ("stringybark") or scales, and don't seem to shed much.

Up close, the fluffy flowers in capsules and shedding bark of most varieties are the identifying marks.

The ground under many varieties is littered in dead leaves, bark strips, and smaller broken branches. The trees produce chemicals inhibiting other plants from growing under them, so the ground under these trees tends to be bare of understory plants. The oil in the trees is highly flammable, thus untended groves of these trees in dry southern California can be a fire hazard.

Blue Gum?

The Blue Gum (Eucalyptus globulus) is supposed to be the most widespread in California. It was imported as a failed experiment in growing trees for lumber and pulpwood in the late 1800's. I believe the following 4 photos are probably this species.

A covering of thin brown bark sheds to reveal white and tan patchy trunk.
Patchy trunk where the bark remains partially attached to the lower part of the tree.

Red Ironbark

If I have identified this common street-lining species correctly it is Red Ironbark (Eucalyptus sideroxylon). Flowers are dark pinkish, stems reddish, leaves greener rather than blue, giving the overall tree a richer green color rather than the typical blue-gray of many other forms. The next 4 photos show this tree.

The hard, furrowed bark gives rise to the name "Ironbark" shared by several species.

Silver Dollar Tree

Local tree trimmers gather fresh cuttings each spring for floral displays. I haven't determined the exact species, but it may be Eucalyptus cinerea. Juvenile leaves of many Eucalypts are round. By trimming trees each year, the rounder juvenile leaves are produced.

One of the "stringybark" forms.
Rounder juvenile leaves are blue-green.
Perhaps also the Silver Dollar Gum, but with mature sickle-shaped leaves.
Unknown species

A massive, messy, untrimmed tree. Shedding strips of bark are lodged in the crotch of the tree. This species reveals a smooth golden-brown trunk under the strips of gray-brown bark...


Truffula Tree

I don't know what these Eucalyptus are, or if they are only one species. They are wispy, tall, with smooth white-trunks. Some are so tall and slender and bent, with little puffs of leaves way at the tops, that they remind me of the Truffula trees designed by Dr. Seuss in his children's book The Lorax. [Legend has it that the original Truffula tree is a Monterey Cypress at Scripps Park in La Jolla, California, where Theodor Seuss Geisel (Dr. Seuss) lived from after World War II to his death in 1991.]