Prairie Dogs

Photo Credit: Tracy Abell (April 2022)

There are people out there who do not like prairie dogs. You know who you are. But I’m here to change your mind. Let’s start with the fact that they are not pests or disease ridden rodents. Like the rest of us, prairie dogs do get sick. In the case of the plague, prairie dogs get it from fleas. However, they usually die quickly and transmission to humans is extremely rare. Further, while prairie dogs are indeed rodents, they do not reproduce constantly like other rodents. In fact, they reproduce only once a year, in the spring, and give birth to 2-8 pups. Females do not even reach sexual maturity until they are two years old.

People who live near prairie dogs are familiar with their barks and chirps. Those calls are actually a complex communication system used in a colony. There are a variety of vocalizations used for different reasons. One of those is the call to alert others of danger. But it’s not a simple warning to duck and cover. Instead, researchers have discovered that prairie dogs can communicate the size and threat of an intruder. The calls also tell others from which direction the threat is traveling and at what speed. When danger has passed, they will also give the “all clear.”

Prairie dogs also dig an extensive network of tunnels and chambers underground – some of these extend for acres underground. They even have designated rooms. Prairie dogs have a nursery, sleeping areas, toilet chambers, and listening chambers near the entrance to the burrow.

If you are not yet convinced that prairie dogs are amazing, consider this: prairie dogs are a keystone species. You read correctly. Prairie dogs are vital to the ecosystems in which they live, and without them the amount of biodiversity drops dramatically. To start, prairie dogs are an important food source for many other animals. Yet they are equally as important to the prairie itself. The burrows prairie dogs dig aerate the soil and let water in. The digging also recycles the nutrients in the soil. And, of course, prairie dogs help fertilize that soil. All of this activity increases the diversity of flowers and grasses on the prairie. The flowers, in turn, attract more bees and butterflies. Prairie dogs keep the prairie open and free from trees and shrubs, which further increases the diversity of grasses. The diversity of grasses attracts more prey animals which, in turn, attracts more predators. In addition, abandoned burrows provide shelter for other species, including burrowing owls, snakes, and critically endangered black-footed ferrets.

So next time you see a prairie dog, consider all they do to maintain a healthy prairie ecosystem!

Is It a Crow or a Raven?

I’ve always been a fan of crows and ravens, mostly because they are part of the corvid family of highly intelligent birds. Corvids have large brains, can recognize human faces, use tools, and are incredible problem solvers.

Photo Credit: Rawpixel

Yet unless crows and ravens are standing next to each other, they are hard to tell apart. So I did a little digging. I already knew that ravens were larger than crows, but apparently ravens are the size of red-tailed hawk, an easy comparison to remember. In addition, ravens tend to travel in pairs while crows are often in larger groups.

If you see a large black bird flying overhead, one way to tell whether it is a crow or raven is to look at the tail feathers. The tail feathers of a crow are all the same length, so when they spread out during flight they look like a fan. Ravens, on the other hand, have middle tail feathers that are longer than the others, so during flight their tails are wedge-shaped. Further, if you see one of these birds soaring for more than a few seconds, it’s probably a raven. Crows flap their wings more. Finally, if you are close enough to the bird to hear a swishing sound produced by the wings, it’s a raven. Crows flapping wings are mostly silent.

A final way to tell these two bird species apart is to listen to them. Crows make the stereotypical high-pitched cawing sound. Ravens’ calls sound more like a low-pitched croaking. While that sounds like a simple distinction, I think it will take listening to a few sound recordings to be able to learn the difference. Still, bring on the corvids. I want to see if I can now tell them apart. Of course, I can always use Merlin’s Bird ID app to confirm (or not). And the bird in the photo? It’s a crow.

Predaceous Diving Beetles

On a hike this fall, once we reached our lakeside destination and ate lunch, I spent some time marveling at the view around me. Then my attention turned to the water. At first glance there was not much to see below the surface. But as usual, a little patience paid off. There! A small critter about an inch long darted through the water from one hiding place to another. It immediately reminded me of the grey sand crabs I used to dig up as a kid on the Maryland shore, though the one in the lake had black and white stripes. But we were a long way from Maryland, both in miles and elevation. This lake is in Colorado at about 10,000’.

I kept watching. There was only one. It swam effortlessly, then hid. I snapped a few pictures. At home I studied the pictures and looked it up. Unable to identify it, I sent the picture to the National Park Service (they’ve helped with identification of various things before). They were slightly stumped too, and my email was forwarded several times. Eventually the ID came back as a predaceous diving beetle.

I had already concluded that it was some kind of beetle, but had no idea that beetles actually swam. Or even lived in water for that matter. Of the more than 24,000 beetle species in North America, about 4% are aquatic. As I had discovered from watching the beetle in the lake, they have powerful, hairy hind legs for swimming. Yet while they are aquatic, they do not spend their entire lives in water.  Eggs are laid above the water on plants; when they hatch the larvae (called water tigers) will fall into the water. Once mature, they crawl out. They pupate in the damp soil and vegetation by the water. Once they reach adulthood, they reenter the water. They do breathe air, so when under water, these diving beetles carry air with them so they can stay under for an extended period of time, like a scuba diver with an air tank.

As their name suggests, these beetles are carnivorous predators, hunting insects, tadpoles, small fish, snails, and even other water tigers. When they grab prey, they inject it with an enzyme that begins the digestive process. The innards of the prey liquify, making it easier for the beetles to extract. The adults are also chewers and will eat carrion. Be on the lookout in a lake near you – there are about 500 different species of predaceous diving beetles in North America.

Pika

Indian Peaks Wilderness, July 2022

I will readily admit that when I’m in the mountains above tree line that I’m always on the lookout for marmots. They are among my favorites. More recently, though, I’ve had a growing fondness for pika. These small mammals are in a family related to rabbits, not rodents. And they’re adorable – they have pudgy, egg-shaped bodies only 6-7 inches long, they have short, rounded ears, and no visible tail.

Pika are especially adorable when scampering back to their underground hideouts with bunches of grasses and flowers sticking out from either side of their mouths. In this sense they are farmers, harvesting plant material to cache for the winter because they do not hibernate. Their stockpiles are appropriately called haystacks. But what’s even more interesting about these stores is that some of the vegetation is toxic. Somehow they know this and will store these materials at the bottom of the pile. Not only does this help preserve other plants, but the toxins break down over time and can be eaten safely late in the winter.

In the high county pika are found in open rocky meadows or boulder fields. They chirp or squeak, alerting us to their presence (or more likely, alerting other pika to our presence). But finding them isn’t always that easy because their fur color perfectly matches that of the boulders. You have to stop for  moment to watch for movement. If you do, your patience will be rewarded.