Harbingers of Spring
By Katie Alvin Explore Big Sky Contributor
Despite our mucking through winter’s lingering grip, birds and butterflies are returning to southwest Montana, ushering in spring.
In the first week of April, the noisy chatter of robins at dawn re-entered the aural landscape, bluebirds were spotted reclaiming meadow nest boxes, and butterflies have begun to emerge from their winter slumber (yes, butterflies hibernate!).
This time of year, birds that migrated south for winter will return to join those that overwintered here, and all of them will be jumping right into breeding season. In order to successfully mate, males need to both attract a partner and defend their territory from competition. For songbirds, singing accomplishes both these tasks.
All birds make vocalizations, but what makes songbirds different is that they must learn their song. Early in the season many sound clumsy or awkward. If you listen carefully, you may be able to hear a bird’s song change over time, becoming more smooth, coordinated, and melodic as the season progresses.
Common birds to look for in spring include mountain or black-capped chickadees, dark-eyed juncos, robins, bluebirds, red-winged blackbirds, and warblers. Watch for nesting bald eagles as well.
Two great resources for identifying and learning more about birds are Cornell’s ornithology website allaboutbirds.org, and the eBird app for smart phones.
Another indicator that spring is near is the appearance of butterflies. Butterflies begin as eggs and caterpillars then form a chrysalis and, after metamorphosis, they emerge as winged adults. So how could a fully formed adult butterfly appear after months of snow and freezing temperatures?
Many people don’t realize that some butterflies hibernate as do many other insects. Most bugs overwinter in their larval or pupal form, but those with longer adult life cycles will actually hide out and weather the long Montana winter in their adult form. In all cases, biological adaptations help these bugs either prevent the freezing of their bodily fluids, or allow them to withstand the freezing temperatures.
As days get longer, butterflies that have wedged themselves into tree bark or roof shingles re-animate as sun warms their bodies and makes it possible for them to fly. After being hidden in hibernation for months, they emerge bringing a welcome burst of color and life to the snow and mudscape.
Three common early season butterflies are all from the same family and have matching rough-edged back wings to prove it. The mourning cloak, which is Montana’s state butterfly, is often one of the first sighted. It has dark wings with a row of blue dots and a distinctive yellow band at the bottom.
Milbert’s tortoiseshell is a smaller, similar butterfly, with a row of yellow and orange at the outer edge of its wings. Your first sighting could also be a more conventional orange and black “comma” butterfly, named for the silver comma-shaped mark on the less colorful backside of its wings.
Young or old, it’s hard not to get excited about these signs of life and the emergence of spring. There is plenty to see if you look for it, so get outside and welcome the changing season!
Katie Alvin has lived in Big Sky for more than 20 years. With degrees in Environmental Studies and Soil Science, she has been involved with environmental and outdoor education for 25 years, and owns East Slope Outdoors with her husband Dave.