Post written by Alexa Leinaweaver, Live Animal Husbandry Coordinator

Happy World Wildlife Day!

 

Wildlife, while traditionally meaning all non-domesticated animals in an area, has expanded to mean all the fauna, flora, and other kinds of life. All species have evolved to be dependent on each other. Sustaining all kinds of life on our planet can only help the human race survive and prosper.

Some individual species are so vitally important to an individual ecosystem that they are considered to be a keystone species. So many other kinds of life depend on the keystone species that it would have a disproportionate effect if it should be removed from the ecosystem.

Colorado has amazing diversity in its wildlife. With the massive changes in altitude from the Rocky Mountains down to the Great Plains, the wildlife that live here have adapted to a wide range of micro-climates. With the variety of ecologies in the area, there are many keystone species that keep the whole system healthy. Some local examples include:

In the Mountains: Aspen trees

Quaking Aspen (Populus tremuloides) are, for many, a symbol of the Rocky Mountains. They cover 20% of Colorado’s forested land, or 5 million acres.

Aspen are a keystone species, supporting many birds, insects and mammals throughout the year and creating a highly biodiverse ecosystem. Because aspen love sunlight, groves are more open and bright than an evergreen forest. More variety of plant species can grow in the understory below an aspen grove. Additionally, as aspen are short-lived (70-150 years), they quickly add nutrients back into the soil around where they fall. Aspen propagate both with seeds and via cloning. A grove of clones can send up tens of thousands shoots per acre – which many grazing animals love to eat. Aspen shoots are actually higher in fat than many plant species, making it an especially important winter food source for deer and elk. The white bark of the aspen tree can also be used by many species as a food source in winter (elk, deer, beaver, rabbits, voles, mice, etc.), and year-round by a wide variety of insects. Several kinds of woodpecker, chickadees, nuthatches, kestrels, owls, and wood ducks will nest in the aspen.

Aspen trees are unfortunately in decline throughout the Rockies, up to a loss of 60-90% depending on the local climate. The primary cause is believed to be human behavior. Human efforts at fire suppression have allowed conifers to spread into aspen groves, shading the aspen and preventing them from thriving in the sunlight they love. Fire is also a natural part of the aspen’s life cycle: as the older above-ground aspen declines in health it should be cleared out by fire, prompting new sprouts. Without the fire, the sprouts are fewer and grazing animals have more impact on the grove. As the Aspen trees decline, hundreds of species will suffer.

In the Prairie: Prairie Dogs

Prairie dogs (genus Cynomys) are a group of intelligent, burrowing rodents – actually a kind of ground squirrel – native to North American Grasslands. In Fort Collins area, you will see the Black-tailed Prairie Dog (Cynomys ludovicianus). Prairie dog colonies will dig a complex maze of burrows as their colony’s home for breeding, raising their young, and hiding from predators, maintaining the town over several generations.

Prairie dog activities change the grassland ecosystem that they live in; they are often labeled “ecological engineers” for the way they shape the world around themselves. Burrowing will actually alter soil chemistry, as well as aerating the soil. Their grazing (both above and below ground) affects the plant life they live in, encouraging more diversity of plant species and plant productivity. The soil becomes richer in nitrogen and more fertile, supporting both more plants and a wider variety of insect life. Because of the positive effect prairie dogs have on the soil and the plant life above, grazing animals (including domestic cattle) often prefer to eat in the middle of prairie dog towns as the forage is better. Prairie dog burrows provide shelter and nesting habitat for many animals, including black-footed ferrets and burrowing owls. Prairie dogs are also a vital food source for a wide variety of predators: hawks, owls, ferrets, coyotes, badgers, bobcats, and rattlesnakes.

Prairie dogs numbers are vastly reduced from their historic populations. Many people believe that prairie dogs are pests, damaging crops or putting domestic animals at risk, and have actively persecuted the animals (e.g. target shooting, poisoning). Humans have also taken up most of what was originally prairie dog territory for agriculture and suburban sprawl. Between 1900 and 1960, 98.5% of prairie dog habitat was lost. Additionally, humans accidentally introduced the bacteria that caused the plague to spread, which can quickly wipe out entire colonies of prairie dogs. Even if you agree that they are pests, the loss of prairie dogs to our grassland ecosystems would have an enormous negative effect on hundreds of other species.

Celebrate World Wildlife Day

Celebrate World Wildlife Day this year by learning more about your local wildlife! Explore one of our many beautiful natural areas and observe the way that the wildlife interacts with each other. Or, visit the Fort Collins Museum of Discovery this weekend and see our Natural Areas Exhibit. Watch the Ferret Feeding Frenzy at 2:30 on Saturday or Sunday! This is not for the faint or squeamish of heart…

Continue Reading

Post written by Alexa Leinaweaver, Live Animal Husbandry Coordinator.

National Bird Day: Winter Birds

Weather changes, snow is falling. But when you look out your window, there are still a bunch of birds hanging out. Which birds are here in the winter, and how do they survive?

Migration

Migration is a strategy that many animals use to cope with seasonal changes. Generally migration seems to be triggered by birds following their food supply or seeking a new type of food, as well as seeking more comfortable weather conditions.

We are most familiar with migration from an area closer to the poles in summer, and toward the equator in winter. This is known as Longitudinal Migration, as it is on a north-south axis. Migration distance can range from thousands of miles each way to only a short distance. While we mostly think of birds leaving Colorado for warmer weather, we get some migrants coming to stay here from much further north. Some examples of birds that migrate to the Fort Collins area for winter:

• The Dark-eyed Junco spends its summers breeding in Canada and Alaska, and moves down into the continental United States during winter. Juncos are easily recognized by their behavior, hopping around the ground seeking food, and the black and white flash of their tail when they take flight. They are colloquially known as “Snowbirds”.

• The Rough-legged Hawk breeds in the Arctic, but winters in the U.S. and southern Canada. It gets its name from the fluffy feathers covering its legs – an excellent adaptation for a bird that spends its summers in the Arctic as well as for our snowy Colorado winters.

• Most Bald Eagles spend their summers further north in Canada and Alaska. They will migrate into Colorado in winter where they breed, usually January through March. (We do have some year-round resident bald eagles in the area as well.)

There are also birds that migrate a short distance, but for a big change in altitude: Altitudinal migrants. Most of the altitudinal migrants in the U.S. are in the American West, thanks to our Rocky Mountains. Many of us humans have experienced the dramatic difference in weather and temperature between the plains and up in the Rockies.

• Most Prairie Falcons winter in the Great Plains, hunting Horned Larks and Western Meadowlarks. In summer, they move up to 11,000 feet in search of abundant ground squirrels and pikas.
• The Townsend’s Solitaire spends its summers in the mountains, then moves to lower elevations in winter. They switch food sources from mostly insects in summer to fruit, mostly juniper berries, in winter. They can get extremely territorial over their chosen patch of juniper trees, defending them against solitaires and other bird species.

• Immature Mountain Chickadees are known to migrate to lower elevations. However, once they are old enough to select a breeding territory, they will generally stay there year-round. (It can be very challenging to distinguish them from our usual Black-capped Chickadees who stay in Fort Collins area year-round. Look for a white “eyebrow” on the Mountain chickadee that the Black-capped lacks.)

Other Adaptations for Winter Survival

For us humans, it seems logical to escape the cold and snow by going south for warmer weather. But birds have amazing adaptations to help them survive weather that we find daunting.

• Feathers are the best insulation we know of. Imagine curling up inside a cozy down overcoat – birds have one naturally! They can retain heat by fluffing out their feathers, trapping more air underneath to keep them warm. Birds like chickadees or wrens fluff up so much that they look twice as fat in winter! Many birds, like the American Goldfinch, will also change out their sleeker, brighter summer coat for a thicker, drabber winter one. They get better camouflage as well as better insulation.
• Some birds, like crows, will cluster together and share body warmth. Smart birds like crows and other corvids can also communicate about food sources and predators.
• Many birds will also plan for the winter by putting on fat. It acts both as insulation to keep warm and as an energy source if hunting for food doesn’t go so well.
• Birds are also good at predicting when the weather will turn bad and a blizzard is coming. They will eat extra food in advance of the storm, then hunker down and save calories for body heat while it snows.
• Several species will change what kind of food they eat. The Townsend’s Solitaire and Prairie Falcon, described above, are great examples. Some birds will also stash food in preparation for the cold – if you have a birdfeeder that gets extra busy in fall, some of your avian visitors are probably caching food for later.

Birding in Winter

Celebrate National Bird Day this year by spending some time outside, looking at our seasonal visitors! But remember, winter can be a difficult season for any wild animal. Keep your distance so they don’t waste their precious energy flying or running away from you when you get too close.

Photo courtesy of  Alexa Leinaweaver.

Continue Reading