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Nature Update on the Yellowstone Ecosystem by Leslie Stoltz, YNP Naturalist

April 7, 2020 Nature News from GYE#1

This is my first ever Newsletter from the Greater Yellowstone, where I live.

In the time of Covid-19 it seems time to send some news about what is happening in one of the largest intact ecosystems of the temperate zones on earth. Yellowstone and Grand Teton National Parks are the core of GYE, but all together this region is approximately 18-20 million acres. This landscape is one of the world's foremost natural laboratories in landscape ecology and geology! My hope is to bring you a bit of news each week to let you know what is happening as the seasons change and much more. Each week I will describe a bit about how Greater Yellowstone is a functioning ecosystem and finish with a tidbit about a specific living part of this region. Despite the fact you can’t visit Yellowstone in person, it can still be a part of your lives!

Our winter season, which sometimes can begin as early as October, is starting to show signs of letting go. More sunlight after spring equinox and more reflective energy

starts the snow melt. We’ll still have snow falling occasionally, but the light stays longer and the ground is warming. Because of varying elevations and temperatures in the park, the spring season can start anywhere from mid-March all the way through late May. Spring is the time for new life. That’s certainly the case in Yellowstone. Black Bears and Grizzly Bears start coming out of dens mid to late March but mothers with cubs will be a bit later with their emergence.

Late April we start to see bear cubs. Bison give birth to just one calf in late April or May. The cinnamon-red calves stand out so beautifully when the grasses grow emerald green. Calves are born ready to go and can keep up with adult bison two to three hours after birth. Elk calve in May to late June. An elk calf can stand by the time it is 20 minutes old. Calves can often be seen in a “nursery group” of cow elk and other calves. Bull elk are on their own.

Predators watch the movements of the mother to try to see where the young are hidden. Predation is usually a matter of chance for wolves, coyotes, and cougars. Both bear species, however, have an extremely keen sense of smell and bear (despite the fact calves have almost no scent for the first few weeks) often account for the majority of fawn (deer) or calf (elk) mortalities in the first couple of weeks. Pronghorn have their fawns later in May. It is not uncommon for twins with this species. Coyotes are the main predators for the Pronghorn fawns. Young of many species are difficult to see as they have cryptic coloring and spend a lot of time hidden in the vegetation. Other species of young mammals we will start to see later in the spring are wolf pups, coyote pups and maybe even some fox pups.

Bird species that have not spent the winter here are starting to head back to this region. Today I saw my first Mountain Bluebird in this section of the Gallatin River. On my ski yesterday I heard the first Robins and Song Sparrows. This was a sign that Mountain Bluebirds would return soon!

Another clue I had was the presence in insect life on the soft snowpack. Stone flies emerge close to the river, on which the Bluebirds feed. An interesting insect-like critter, which is actually a hexapod, is a harbinger of spring is called a springtail or snowflea. They are found in clusters of hundreds or thousands and look like darks specs on the snow or around the base of trees. As days get warmer they rise to surface of the snow looking for different food sources. Upon closer examination you will see these specs are, in fact, teeny hexapods which are jumping quite a distance (hence called fleas). Fleas used enlarged hind legs and springtails use an appendage called a furcular, which is like a tail. Springtails are not parasites like fleas. They feed on decaying organic matter and play an important role in the nutrient cycle. They can withstand the very cold temperatures of winter as they produce an “anti-freeze” like protein. This binds to any ice crystals that might start to form in their tissue and prevents freezing. Isn’t nature amazing?

As I sit outside listening to the chickadees and snow melting (drip drip drip off of the roof) I am grateful to be in this amazing place on earth and look forward to sharing more information about Greater Yellowstone with you.


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