Poking Around in Arizona

Kofa National Wildlife Refuge - Arizona
by Craig Mains

During our week in Yuma, Corbin and I took a day trip to Kofa National Wildlife Refuge, which is northeast of Yuma. We did a short hike in Palm Canyon, which is shown above. This view is looking roughly east. The peak in the background is Signal Peak, which is the highest point in the refuge, at 4877 feet.

Palm Canyon is noted for having what is believed to be the only stand of native palm trees in Arizona. This view is looking roughly towards the north from inside the main canyon. You can see the mountain is weathered into a number of steep, narrow, side canyons. The canyon in the middle of the photo is the canyon that has palm trees growing in it.

A closer view of the narrow side canyon with the palm trees, which are California Fan Palms, Washingtonia filifera. They are believed to be descendants of palms that grew more widely in the area during a time when it was cooler and wetter. As the climate changed to desert conditions the palms were restricted to growing in protected niches such as this one. Although the side canyon faces south, it is so narrow that it is in shade most of the day and is probably able to retain some moisture.

I've read that there are about 100 palms growing in the side canyon. It didn't look like there were that many to me. From far away it looked like maybe two dozen. There is supposedly one palm in one of the nearby side canyons and the others have no palms at all.

A closer view. The side canyon is so narrow that the palms appear to grow in almost a single line of trees. The skirt of dead leaves near the tops of the trees is visible. Palm trees are so ubiquitous in urban areas of Arizona that it seems odd to think these are the only native palms in the state. However, most of the palms in Arizona cities are cultivated. The towering palms in Yuma are the related Mexican fan palms, Washingtonia robusta, which are native to the Baja California peninsula. They have since been cultivated in other areas and naturalized in many areas outside of their original range including the US Gulf Coast and parts of the Middle East and Mediterranean area. A number of other non-native palms are grown as ornamentals in Arizona.

A Palo Verde tree in Palm Canyon. Because they have chlorphyll in their branches and twigs they are able to survive despite having few leaves. These seemed to be most common along the dry washes.

Looking towards the west from the mouth of Palm Canyon. The canyon was in the shadows during the time we were there.

Another view of the bigger canyon. The side canyon with the palms would be about midway on the left side.

After Palm Canyon, we wandered around in the desert off of King Road. Here is a view of the Kofa Mountains in the background. Although they are not particularly tall, they have weathered into jagged spires.

The Kofa Wildlife Refuge was established in 1939, primarily to save the Desert Bighorn Sheep, of which there were believed to be only about 150 remaining in Arizona at the time.

We spotted two of these Deer Tooth Boxes. They both had a slot on the side of the box to slip the teeth into. I'm sure they are research related. I've read that a lot of information can be learned from deer teeth, similar to that from tree rings or fish scales. I'm puzzled by the purpose of the boxes though. Who is supposed to deposit deer teeth in the boxes? Is the box for hunters? If so, is it a voluntary program? Are they expected to carry pliers to extract a tooth? Is there a preferred type of tooth for this purpose? So many questions.

The Kofa National Wildlife Refuge covers about 1040 square miles. It is named for the King of Arizona mine that operated in the area from 1897 to 1910. The mining company once marked their equipment and property with the abbreviation: "K of A." This got further shortened to Kofa. Gold, silver, lead, zinc, and copper were once mined in the area.

Despite being extremely dry there are some holes eroded into bedrock, referred to as "tanks," that hold surface water for parts of the year. Besides deer and mountain goats, the refuge is home to the desert tortoise, cougars, kit foxes, and a variety of birdlife.

The Kofa National Wildlife Refuge is considered to be part of the Yuma Desert, which is a sub-section of the Sonoran Desert. It is a mostly low-elevation desert in the southwestern corner of Arizona. With rainfall less than eight inches per year it is considered one of the harshest deserts in North America. Vegetation includes creosote bush and saguaro, ocotillo, and cholla cacti.

One of the common cacti in Kofa was the Teddy Bear Cholla, Cyclopuntia bigelovii. Its spines are spaced so densely that it gives it a somewhat fluffy appearance, reminding some of a teddy bear---only much less cuddly. Its native range is southwest and south-central Arizona, southeastern California, the southern tip of Nevada, and northwestern Mexico.

It propagates mostly from segments of the plant becoming detached and either falling nearby, or being blown or carried to a new location by animals that may brush against the plant. If it ends up in a suitable location, the detached segment may root and form a new cactus. The fruit, visible in the photo, typically don't have many seeds.

Some smaller peaks of the Kofa Mountains in the background. Cholla cacti in the foreground.

December 2019

 

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