Some birds show astounding site fidelity, the same individuals or populations returning year after year to the same small patch of habitat to breed or overwinter, sometimes even showing up within a few days of the same date every year. As territorial animals, birds are likely to defend and return to a favorable site that offers the things they need: food, water, shelter, and, seasonally, suitable breeding habitat.
Last year, on our annual day-after-Thanksgiving adventure, Eric and I were privileged enough to watch two Short-eared Owls hunting over the grasslands south of the wetlands at Merced National Wildlife Refuge. This year, we repeated the outing, spending the day exploring the vast grassland and wetland habitats at San Luis and Merced National Wildlife Refuge.
As the sun began to sink toward the western horizon, we found ourselves along the same stretch of road that we traveled on the same day last year, at the same time of late afternoon.
As soon as I pulled over and parked in what has now become our designated owl-watching spot, I spotted the tell-tale long-winged, round-headed silhouette and buoyant flight of a Short-eared Owl, coursing low over the grassland.
The Short-eared Owl was hunting over the exact same patch of grassland as last year, dropping again and again down into the grass on potential prey. After a while, the first owl was joined by a second.
Of course, I have no way to be certain, but my guess is that these two owls are the same two that I saw in this spot last year.
Short-eared Owls breed in grasslands across the northern third of the United States, including Northern California, as well as Alaska and Canada. For the winter, they move south into the rest of the U.S. and Mexico. Both breeding and wintering habitat includes open areas of low vegetation, such as grasslands, wetlands, tundra, dunes, and agricultural fields. On their northerly breeding grounds, female Short-eared Owls build nests on the ground, where they are concealed by vegetation, lining shallow bowl-shaped scrapes with grasses and feathers. Interestingly, they are one of the few owl species that build their own nests; most other species make use of existing abandoned nest sites, constructed by other groups of birds. Larger species, like Great Horned, Long-eared and Spotted Owls tend to refurbish stick nests built by diurnal raptors or corvids, while smaller species, like Northern Pygmy, Northern Saw-whet and Western Screech Owls, are secondary cavity nesters, utilizing existing nest holes previously excavated by woodpeckers and the like.
The habitat favored by Short-eared Owls, along with their hunting style, tells us something about their preferred prey. Primarily, they hunt small grassland mammals, such as mice and voles, as well as gophers, moles, shrews and rats. At around 15 inches long, with a three-foot wingspan and weighing up to one pound, Short-eared Owls are medium-sized owls, capable of taking larger prey. In addition to smaller mammals, rabbits, lemmings, weasels and muskrats are occasionally taken, along with shorebirds, terns and rails where they are available.
Short-eared Owls are just one of many magical grassland animals that may be encountered this winter by intrepid explorers willing to venture out of town, and their presence in wild corners of the Great Central Valley illustrates what an incredible place this largely over-looked region truly is.
Read about last year's encounter with Short-eared Owls by
clicking here.
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