The bat haven at Milo McIver State Park (2013)
The third story in a four-part series about “the hidden side” of Milo McIver State Park.
Did you know that Milo McIver is home to one of the few nursery colonies in the state for a special type of bat? It’s the rare Townsend’s big-eared bat, which looks as amusing as it sounds. Its Latin name is Corynorhinus townsendii (try saying that five times fast), and it’s listed as a sensitive species in Oregon.
Park staff discovered the bats living at Milo McIver about 15 years ago. Each summer, female big-eared bats gather to roost in a weathered horse barn that was once part of an old homestead—you can still see fruit and nut trees that were planted by the former owners in the surrounding meadow.
Today, the meadow and the barn are a haven for six different types of bats, including the little brown bat and you guessed it, the big brown bat. Bats aren’t able to bore holes in wood or make nests, so they find tree branches, caves or man-made structures where they can roost. A barn is an ideal place for bats to raise their young because it stays warm and dry throughout the rainy winter. As many as 70-80 bats have lived in the barn during the summers. In 2002, the park’s bat housing options expanded when Eagle Scouts built eight bat houses on posts for the animals.
Female bats have a single pup—yes, a baby bat is called a pup—each year and use a special call to find their baby in the colony. They nurse the pups until fall, when the young bats are strong enough to fly and venture out for food, using echolocation to hone in on moths and mosquitoes. Echolocation is sort of animal sonar. The bat makes sounds and then listens to the echoes bouncing off nearby objects. The echoes help the bats find an object’s location, size and movement.
Bats sleep during the day, but if you go at dusk, you might see them fluttering about performing their natural pest control. July through September is the best time to spot them: park at the equestrian area in the Riverbend day-use area and walk the 1-mile, self-guided nature trail through the meadow, an off-leash area that your dog can romp in while you take in a view of Mt. Hood to the north. Just don’t enter the barn—nursery colonies are very sensitive, and mother bats may abandon their young if disturbed.