Desert Destination: Wildlife in the Fields

Mule deer in alfalfa field

Sometimes I travel long distances to go look for wildlife, but today I didn't have to go far. Wildlife love coming to the ranch. They have lots of food, good cover, and of course, good company. So to celebrate some of our animal neighbors, here's a series of photos of these creatures saying hi. (Or saying get the heck out of here and let me get back to my business, but if they're saying that I'm just pretending not to understand.)

Canada geese flying overhead

Canada geese taking off from field

Ravens on fence next to corn field

Mule deer near pivot

Mule deer eating alfalfa

Group of pronghorn antelope in recently cut hay field--

sorry these are little specks, but the shadow of the airplane is cool, isn't it?

Mule Deer Buck

I had some fun testing out my new camera on this cooperative mule deer buck. Mule deer (Odocoileus hemionus) are found throughout western North America and are larger than their eastern cousins, white-tailed deer (Odocoileus virgianus). Mule deer have large mule-like ears and a black-tipped tail. 

They also have antlers that fork as they grow. The antlers begin growing in the spring each year and are shed after mating, from mid-January to mid-April. Many people scour the hillsides to pick up these shed antlers to make art out of them, particularly antler chandeliers, lamps, and fireplace tools. In locations where chronic wasting disease has broken out, like Colorado, many artisans choose to make their creations out of fake antlers.

This buck appeared to be enjoying some of the fall colors. He was not far from the road, despite it being hunting season. And he didn't even get up when we walked by. Question: Why would this apparently healthy deer be so tame?

Answer: We were in a national park, so this smart buck knew that he wouldn't be shot. If you're a hunter and reading this, don't despair, many nice bucks leave the national park and are shot outside of it. And the ones that don't leave produce offspring that go out and find new territory.

This buck probably weighs between 200-300 pounds. Females are smaller, and both eat a variety of vegetation. If a mule deer can escape predation by mountain lions or hunters, disease, and hunger from drought years, it is likely to live up to 10 years.

Mystery Birds

I walked out of the house the other evening and saw a nearby tree filled with these large black birds. It was getting late and the sun had already set, so I didn't get a good close up of them, but perhaps you've seen them before. They come occasionally to the trees and congregate like you see in the photo. The next morning, to my surprise, they were gone before the sun rose. Do you know what they were?

A Robber Fly

Today I'd like to introduce you to a Robber Fly, also known as an Assassin Fly or a Bee Killer. It belongs to the order Diptera (flies) and the Asilidae family, a huge family with 1,000 species in North America. This family is fierce, killing other insects, hence the violent common names. It's sort of like what a falcon is to other birds--out there watching and ready to dive in for the kill. The Robber Fly isn't fussy, it will eat just about any flying insect out there, including bees, wasps, dragonflies, grasshoppers, and other flies. Using its big eyes, it spots its prey, swoops down on it, and captures it mid-flight. It takes the prey to a perch and injects enzymes into the insect that immobilize it and start digesting it. Then the Robber Fly slurps up the liquid meal. Yum.

This is a male Robber Fly, probably in the genus Efferia, with 100 species in North America. Males have white bulbous claspers on the tip of the abdomen. Females have a swordlike ovipositor that extends from the abdomen and allows them to deposit eggs in dead flower heads, cracks in the soil, and other tiny spots.

The Robber Fly family can be distinguished by the "bearded" face, with lots of hair on it, and the concave top of the head between the eyes. That concave feature makes its large compound eyes seem really "buggy." The legs are strong and bristly, the better to hold onto its prey.

Do you see that sharp proboscis? Within it is a lancet, an even sharper pointy object. It allows the Robber Fly to stab its prey and inject fluids. It's reportedly sharp enough to pierce human skin, but fortunately Robber Flies haven't developed a taste for human flesh. Yet. (Insert cackling laugh here.)

Larvae overwinter in soil and emerge in the spring. It is thought that more species of Robber Flies still need to be described. Robber Flies are particularly common in sunny and arid areas and are most active during the warmer parts of the day, but I have to admit that I only noticed it for the first time this summer. It is so amazing how many different insects live so close to us and yet we know so little about them!

A Wild Horse

Last week I saw a wild horse (Equus caballus) out on the desert. It was a beautiful horse, and it looked powerful and free, important concepts in the United States. Seeing the horse took me back to another time, before there were barbed wire fences dividing up rangeland, before modern comforts of one-ton diesel crew cab pickups with air conditioning, before urban sprawl. 

Even as I was admiring the horse, I was concerned. One wild horse can find plenty of food and water out in the desert, but there's not just one. These descendants of escaped horses and mules from miners, settlers, and others have been bountiful reproducers, and some herds number over 100. These herds can be exceptionally hard on the delicate desert ecosystem, trampling fragile water sources, overgrazing, and pushing out native wildlife.

The ancestors of this horse came over to North America first via conquistadors in the fifteenth century, and then over time by various other travelers from Europe.  Equus caballus was not the first horse in North America; horses crossed the Bering Land bridge from Asia thousands of years ago, but they eventually died out. Bones from what is believed to be Equus scotti have been found in a nearby cave. 

I should mention that the term "wild horse" is used by some to refer to only horses that aren't descendants of horses that have escaped from domestication; these horses are called "feral horses." Nevertheless, thoughout the West, wild horse is the term most often applied to any horses that aren't owned by someone. 

The Bureau of Land Management (BLM) has a large wild horse and burro program. They periodically round up horses that have exceeded the BLM-determined carrying capacity and then offer these horses for auction or adoption. Usually more horses are available than are wanted.

I'm wondering if this horse is going to find some others to associate with. Usually the horses are found in small bands with a dominant mare, additional mares, foals, and one stallion. Where ever it's going, I wanted to share with you a glimpse of the American desert and a sight that's not seen every day. 

Looking for Fish in the Desert

It always amazes me that fish can live in the desert. These little creatures that require water year round are playing an amazing gamble with their lives choosing to live in such a parched area. Haven't they studied the odds? Gambling isn't a safe way to live! 

It turns out that many desert fish species used to live in a lot of water, about 10,000 years ago when huge lakes covered many areas of the Desert Southwest. We live next to the Bonneville Basin, where a huge lake the size of today's Lake Michigan flooded many of the valley bottoms. Many different fish species lived in the lake, but as it dried up, they became restricted to small bodies of water. One such fish species is the least chub (Iotichthys phlegethontis), a tiny minnow-like fish that rarely gets more than two inches long.

I set off one warm morning to help some fish biologists locate these fish. We went to a huge marsh area that has many small springs providing green spots among the more mundane-colored vegetation.

Here is Brooke, ready to measure the depth of the spring as a standard habitat measurement. I want you to notice that the pole she is holding is seven feet tall. The spring is under the thick green vegetation by her feet.

Where's the pole? Look closely, Brooke is still holding it, she's just holding the top of it. The rest of the pole is in the spring, over six feet deep. One wrong step in this marsh and you're literally in over your head.

Take a few steps in another direction and you find the salt marsh stretching off to the distance, as dry as can be. During the spring, a nearby playa fills with water and shorebirds stop by to snack on invertebrates during the migration. 

The scattered pockets of water provide opportunities for diverse vegetation, including these cattails. At selected springs, we lower minnow traps into the water and leave them for three hours.

At the end of three hours we go and pull the traps. Some springs only have predaceous diving beetles and amphipods (also called scuds or freshwater shrimp). But sometimes we have luck and pull out a trap with fish in it. We determine the species and measure the fish before releasing them back into the spring.

Here are two of our catches, a speckled dace (Rhinichthys osculus) and a least chub. Seeing them makes me realize the amazing adaptations the native species have made to live out in the desert. So far their gamble is paying off.

Beetles that Swim

Over time we've looked at how some animal species have adapted to live in the desert with little water and hot temperatures. Well, some wildlife have just chosen to live where there is water and cooler temperatures, despite being in the desert.

These spots are few and far between, but they do exist, like this spring out in the middle of a salt marsh. The surrounding soil is very salty, but the water temperature rarely rises above  15 degrees Celsius (about 60 degrees Fahrenheit). 

 
Here is one of the most common inhabitants, Dystiscus marginicollis, a predaceous diving beetle in the family Dytiscidae. As larvae, the long and skinny creatures are known as water tigers due to their predatory nature. 

As adults, they develop a hard exoskeleton and become oval shaped. They move through the water by using their legs as oars, moving their flattened hind legs in unison. They have a bubble of water stored under their wing covers to help them resurface, and they come to the surface tail first. As adults they can also fly around and find the perfect spring to live in.

To me, just the name predaceous diving beetle sounds a little scary. And learning that they are cannibalistic adds to their creepiness. So it took me some time to work up the courage to pick up a beetle to examine more carefully. After all, I didn't want to become part of its prey, even if it was just a nibble. 

After a few clumsy attempts, I finally managed to grasp the beetle and lift it up, making sure that its mouth was far from my skin. The photo doesn't do justice how wiggly the beetle was. It didn't really like me to hold it, and I didn't really like holding it, but I did it for you, the readers of this blog, for your personal edification. I'm sure you will feel intellectually stimulated after reading today's post. (Actually, I think you might be paranoid about these beetles if you see them, but that's really not my intent.)

It has six legs, just like any insect, along with two eyes, antennae, and mandible parts. Those mandible parts are what scared me. They're short but sharp, and anything that's sharp can really get your attention.

This particular species is widespread throughout North America. It has lots of close relatives; the family has about 475 species in North America. 

Apparently some species of these beetles are eaten fairly frequently in China, Thailand, and New Guinea, and are even raised for consumption. They reportedly taste like chicken. No, I'm kidding, the report I read said they taste rather bland. I have to admit that even though I sometimes do strange things, I did not taste this beetle for you. But if you want to taste one, let me know and we'll see if we can sort out something.

Closely related are the water scavenger beetles, in the family Hydrophilidae. Instead of using their legs like oars (both moving together), they use them like paddles (moving them alternately). Another difference is that when they come to the surface, they bring their head up first instead of their rear. 

Both predaceous diving beetles and water scavenger beetles will also eat carrion. So don't fall into a spring and die or you really will become dinner. 

Getting to Know a Desert Short Horned Lizard

9/21/08 I've consulted with a herpetologist and this is indeed a Short Horned Lizard (Phrynosoma hernandesi) rather than a Desert Horned Lizard (Phrynosoma platyrhinos). Short horned lizards are rarer around here than desert horned lizards, and the principal way to tell them apart is by the shape and size of the little horns on the back of their heads. Both species have very similar life histories, so the information originally presented here for desert horned lizard still holds true for the short horned lizard.

I was out wandering in the desert the other day and got lucky enough to come upon a desert horned lizard (Phrynosoma platyrhinos), my favorite lizard. My camera was handy so I snapped a ton of photos. Doesn't the lizard look like he (or is it a she?--I don't even know how to tell) is having a good time being a model? Look at the giant smile and the come-hither look of those dark eyes.

By the way, the desert horned lizard is sometimes called a horny toad, although it's not a toad at all. The name is kind of fun, though. I can see you smirking.

Okay, back to the lizard. The desert horned lizard is the widest and thickest of the lizards we have in our area. Most lizards are streamlined, but the desert horned lizard has survived just fine with its different shape. Part of the reason that it does so well is its cryptic coloring--it blends in with its surroundings so well. Another way it's different from the other lizards are the rows of fringed and pointed scales (spines) along its back and sides. Makes it look a little more dinosaurian. (That's probably not a word, but pretend you know what I mean.)

I was in a saline area, with lots of white salt and soil, and the desert horned lizard was white to match it. In another part of the valley with brown dirt, the horned lizards are browner. The black and yellow speckles look just like lichen, and if the lizard stayed still while you were walking, it would be virtually impossible to see it. However, desert lizards tend to try to run away to the nearest bush if someone approaches, making it possible to spot them. 

The two dark splotches on the neck are characteristic of the desert horned lizard. One of the cool things about this lizard is that it will partially bury itself in sand and wait for its favorite prey, ants, to walk by, and then stick its long tongue out and lift them off the ground and to its mouth and eat them.

Sorry about using the word "cool" so much in this blog. I guess it kind of dates me. I would be a different generation if I used the word "awesome." And the kids today would say that this lizard is "sick." Now back to the lizard--again.

Little baby lizards should be out and about now in August, hatching from eggs that were laid about two months ago. It will take a baby lizard about two years to become an adult, and they live about 5 to 8 years. Because they eat mostly ants and are picky about what ant species they eat, they don't do well in captivity. 

By the way, I almost forgot to point out the horns behind the eyes that give the desert horned lizard its name. But you probably already figured that out.

As the weather gets cooler (which will occur at some point despite the heat wave we're in), the desert horned lizards will eventually go into hibernation for the winter. Then they'll come back out in the spring, ready to pose for pictures. 

Harvester Ants Do Fall Cleaning

I love to go caving but haven't been underground lately. On one of my recent walks, I thought about the harvester ants going in and out of their mounds and realized that they are tiny little spelunkers. They don't even need a helmet or three sources of light or knee pads. And somehow they can adapt to being in the total darkness to coming out to bright, blinding sunlight without pausing at the entrance of their mound.

So in fascination, I stopped at one of the harvester ant mounds and watched these little guys for awhile. They move really fast, so I was happy when I got one closeup photo that looked fairly decent (see above), showing the tiny hairs on the ant's body. If you missed the earlier post about harvester ants, click here to learn some basics about these neat little insects and see some good photos of harvester ant mounds.

As I was peering intently at the mound, I saw a couple smaller ants with darker rears than the harvester ants nearby. I'm not sure if they were a different species or simply a different type of ant from the mound. (If you know, please share!) Both kinds are on the white rock.

The entrance to this particular mound consisted of several small holes on the south-facing side. Since I've noticed that harvester ants always seem to prefer their openings on the south- or east-facing sides of the mounds, I've been examining every mound that I've found. So far I've only found one anomaly, with a north-facing opening. I'll keep an eye on it to see if that mound survives.

Many times the ants went in and out of the holes several times before deciding which way to go. I'm not sure if they were confused or communicating or just playing. Somehow I doubt that ants play, they always seem so industrious.

As I stood squatting with my eyes on the mound, I realized that a few ants were leaving the mound with bits of debris. It won't be all that long till the snow flies, so it's time for them to do some fall cleaning before they spend the winter underground. 

And I was so fascinated with the ants that I took this short video. The quality has been compressed, but I did find some fun music to put to it. Look for the ant that's taking a little white something out of the hole, and later the two ants carrying a dead one. One of those two ants has to walk backwards!

Life at the Beach

A few days ago we were at the beach. Not a beach at the ocean, but almost as good, the beach just a few miles from our house at a nearby reservoir. The water level is down, so it made for good beach observing. One of the most common things we saw on the beach were these small shells.

This little shell was common too. The little girls dug in the sand until they found nice collections of shells. Then they put them into mounds on the boogie boards and compared what they had found. They spent hours doing this, with great dedication and perseverance.

Here's a dead crayfish, about an inch long, that washed up on the beach. The girls were fascinated with it. (The boys were out playing in the inner tubes.)

Not all creatures leave pieces of themselves, so we get to have some fun looking at bird tracks...

...and human tracks (guess who made this one)...

(yes, that's my sandal-tanned foot, isn't it a lovely foot?)...

...dog tracks (if you guessed Henry made this one, you're right and obviously a frequent reader of this blog)...

...and even some deer tracks. See, I got back to wildlife. It just took awhile. I was hoping to see more wildlife tracks on the beach, but didn't want to walk too far. 

And finally I get to see my favorite life on the beach--Desert Boy! What's your favorite thing to see on the beach?