The refuges are rife with wise guys. Baby great horned owls are peaking over the edge of their nests at bird watchers passing below while their wise old parents stay near.
Great horned owls, the same as featured in storybooks and movie clips, are among the first bird species to hatch out young locally, although ducks are following suit. The owls, which can be heard hooting at one another at night, are powerful predators able to take down prey even larger than themselves, but at the same time they are doting parents.
The female Great Horned owl tends to duties at the nest, incubating one to four eggs until they hatch and then keeping her chicks warm and fed. Her mate is the hunter at this time of year, bringing food he’s caught to the nest for the female, who then tears off small pieces to feed to her chicks which hatch out helpless with closed eyes and sparingly little down on their pink bodies.
Once the owlets fledge, or leave the nest, they don’t stray far, and their parents continue to feed them for a while even though they can fly on their own. The owl’s diet is the most diverse of any North American raptor consisting mainly of mammals (including house cats) and birds from ducks and starlings to other owls. They supplement their diet with reptiles, fish, insects, and other invertebrates.
Great Horned owls hunt mainly at night but sometimes do so in broad daylight, like when they have four hungry mouths to feed. While flying to a target meal seems to be the bird’s preferred mode of hunting, the owl has been seen walking along the ground stalking small prey around bushes or rocks.
Much smaller and not nearly as fierce as the Great Horned owl is the barn owl which can be seen at any of the refuges roosting during the day in secluded places. The birds have a whitish heart-shaped face and upper body but are buff colored near their tail. They don’t hoot like their cousins but have an eerie, raspy call.
Barn owls are almost exclusively night hunters. They have keen night vision but the birds’ ability to locate their prey by sound is the best of any animal ever tested. It can hear and can catch a meal that is completely hidden under leaves or snow.
Barn owls swallow prey whole. Twice a day, or so, the bird coughs up pellets of the indigestible parts of what they have eaten. Dissecting a pellet can be an interesting journey into small-mammal anatomy.
Short-eared owls are one of the more widely distributed owl species. Compared to other owls, they are more likely to be spotted in the daytime flying over refuge grasslands or roosting on the ground. One probably won’t see any ear tufts on the birds since those are very short, but its black-rimmed yellow eyes and pale facial disk make it easily identifiable.
Short-eared owls nest on the ground usually on knolls or ridges with enough vegetation to hide the nest and a sitting female. She builds her own nest by scraping out dirt to form a bowl and then lining the bowl with grasses and down.
Also doing well on the ground are burrowing owls which don’t dig in the dirt like the short-eared but claims a ground squirrel’s unoccupied burrow as its own. The small, sandy colored bird with long legs and bright yellow eyes hunts small mammals and insects during the day.
Before laying her eggs, the burrowing owl will line the entrance to her burrow with animal feces which attracts dung beetles and other insects that the owl preys upon. It may also leave bits of litter like bottle caps, pull tabs, cigarette butts or scraps of paper at the burrow’s entrance to signal that the hole is occupied.
The little owl can be spotted by scanning open fields supporting ground squirrel populations. They often stand on dirt mounds next the entrance to their burrow when they are not hunting. Their profile is reminiscent of R2D2 of Star Wars fame. Many reports of burrowing owl sightings have come from those travelling along auto routes in the San Luis National Wildlife Refuge Complex. Go slow, bring binoculars and enjoy all the owls living on the refuges.
The Merced National Wildlife Refuge (located at 7430 West Sandy Mush Road), the San Luis National Wildlife Refuge and the San Joaquin River National Wildlife Refuge comprise the San Luis National Wildlife Refuge Complex. Its headquarters and visitor center are located just north of Los Banos off Highway 165 at 7376 South Wolfsen Road.
The refuges are open to visitors daily from one half-hour before sunrise to one half-hour after sunset. The visitor center is open Monday through Saturday except federal holidays from 8 a.m. to 4:30 p.m.
For more information call 209 826-3508 ext. 127.
