Amazing Migrations

By Steven Grunwald

Birds are the ultimate masters of migration. Ruby-Throated Hummingbirds like this one double their weight from 3 grams to 6 grams before their annual migration to ensure plenty of energy for the journey. Many of them complete a 500-mile trip across the Gulf of Mexico without landing, while others travel over North America in search of blooming flowers. Other birds, like the Arctic Tern, travel complicated routes spanning 44,000 miles from Greenland to Antarctica in a single year. Some birds, like hummingbirds, travel to stay warm and find food. Others, like the Arctic Tern, are determined to find the longest possible days year-round.

These annual migrations have become key to survival in so many species throughout the world, not just in birds. A short list includes: Humpback Whales, Pronghorn Antelope, Monarch Butterflies, and American Bison. Even humans once migrated, and some populations still do each year to follow food or avoid extreme seasonal weather changes. Migration helps animals find food, reproduce and stay warm as temperature and day-length changes throughout a year.

Here on Casper Mountain we experience several different types of migrations. The ones that we will focus on today are altitudinal and latitudinal migrations.

A group of Wild Turkeys is called a "rafter". This rafter was recently spotted crossing Poplar St.

Altitudinal migration is when species move from higher elevations to lower elevations throughout the year. This short-distance migration is impacted by food availability, and seasonal or daily changes in weather. Wild Turkeys migrate down the mountain in the fall to find warmer weather and abundant food. You may have seen these roving bands of turkeys in town during the winter. They like to eat under bird feeders and in yards with lots of pine trees, and occasionally they can be found blocking traffic, as in this photo.

A few weeks ago, Wild Turkeys began migrating back up the mountain and have been making frequent appearances at the CMSP campus. In the springtime, when weather can vary so much from day-to-day, turkeys may move up and down the mountain regularly to follow warm weather and food supplies. If you ever find yourself heading up the mountain in the spring, keep an eye out for migrating turkeys. They can often be found walking along the roadside on their way up and down!

Wild Turkeys enjoy a snack at the CMSP lodge

Latitudinal migration is what most people think of when they hear the word "migration". It is when species move from north to south or south to north depending on the time of year. This is typically a long-distance migration which is impacted by food availability, seasonal day length and weather changes, NOT daily changes. As temperature continues to warm up and day-length increases, we are going to see many migratory birds. Because the top of the mountain is much wetter and colder than the City of Casper, you may see some of these migrants in town before they show up on the mountain.

Western Meadowlark

Mountain Bluebird

Western Meadowlarks and Mountain Bluebirds are two latitudinal migrants that have started to show up in Casper. You may be able to spot them in your backyard or neighborhood, or listen for their distinct and beautiful songs out your window. We will keep you up-to-date as more migrants arrive in Casper and here on Casper Mountain.

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