Starting in Moffat County, collared cow elk migrates over 250 miles to give birth
Imagine walking 250 miles to give birth.
Granted, she did it over the course of several months, but a cow elk in the Bears Ears Elk herd recently migrated from winter range near Maybell to Steamboat Springs and over the Continental Divide to give birth to her calf — a total of at least 255 miles, according to Colorado Parks and Wildlife researcher Nathaniel Rayl.
Elk R190 was collared just west of Maybell in central Moffat County on March 21. She walked just north of the U.S. Highway 40 corridor, crossing Colorado Highway 13 north of Craig, through California Park north of Hayden before dipping south again and walking into the Steamboat area. Here, she zigzagged around the Strawberry Park, Copper Ridge and southern Spring Creek areas.
“We would expect all three of those places to be very good places to calve,” Middledorf said.
But she didn’t stop walking. She entered the Fish Creek area, before finally walking up and over the Continental Divide, giving birth to a female calf in the area of Mexican Ridge in North Park.
Here, researchers used an internal transmitter, placed in the cow elk when she was collared, to learn where the calf was born. They used this signal to find the elk calf and outfit her with a collar that will expand as she ages.
“This little calf right here is going to potentially walk all the way back this year, if she survives the summer and fall,” Middledorf said.
Rayl explained there isn’t really an average distance an elk migrates in Colorado. The same elk might walk a long distance between summer and winter range one year, then stay in the same area the next.
This elk’s migration, though, was a long one.
“This is a significant movement distance,” Middledorf said. “This is probably one of the few places in Colorado where you see that kind of movement. … It’s exceptional.”
This distance is a regular trek for area mule deer, which migrate between summer range in the Steamboat area and winter range in West Routt and Moffat counties, Middledorf explained.
Moose are larger and better able to move through the snow. Their migration is more so one of elevation change, moving up in the warmer months and down the mountain in the cooler months, he said.
Elk in the Bears Ears herd can move from Routt County to Moffat, but many also live in the Steamboat area year-round, skirting the lower elevations just outside of town in the harshest part of winter.
Learning about herd health and more
The elk was outfitted with a GPS collar as part of a Colorado Parks and Wildlife study tracking how many elk calves survive to 1 and what causes their death if they don’t make it to that age. The study, which just moved out of its pilot phase, will ultimately allow wildlife researchers to compare elk in the Avalanche Creek herd in Pitkin County, the Trinchera herd between Alamosa and Trinidad and the Uncompahgre Plateau herd near Montrose.
The goal of this study is to better understand how elk calves make it to adulthood. Researchers will compare elk herds with lower calf-cow ratios — a measure of how many calves are in an elk herd per every 100 adult female elk — to the Bears Ears herd, which has the highest calf-cow ratio in the state.
“We want to know why is this elk herd doing so well up here compared to others?” Middledorf said. “What challenges do these herds face?”
He said this could help the agency make management decisions to help keep elk herds healthy.
They plan to do this by tracking an elk from the time it’s born until it dies or reaches the age of 1.
If a calf dies before reaching 1, researchers plan to collect data about why it died — be it the mother’s nutrition, weather, predators, hunting or a combination of these and other factors.
While this is the main focus of the study, the information collected will be able to serve other purposes.
Rayl said the spatial data researchers are collecting can help them learn how elk are using the landscape, the timing of migration, and potentially, the importance of different migratory routes. They’ll also be able to look at how much public and private land the elk cross in migration, and researchers may be able to identify impediments and pinch points in the animals’ paths.
And while the length of Elk R190’s migration is impressive, there isn’t much to compare it to yet, Rayl explained. Researchers have only collared two elk in the Bears Ears herd so far.
“We only got out two collars there,” he said. “Maybe there are more individuals doing that that we haven’t identified yet. … It’s hard to say how exceptional it is in terms of what we may see if we put out more collars, but it’s certainly striking compared to our other study areas in terms of the types of movement we’re seeing.”
The study launched in the Routt County area this winter. Researchers aim to collar 30 to 40 elk each winter for the duration of the six-year study.
“Studies like these help us understand what these animals are doing on the landscape and, hopefully, preserve them into the future and keep healthy elk herds in the state,” Rayl said.