In 2014, during late fall, multiple Short-eared Owls were found in a weedy, formerly irrigated portion of Chico Basin Ranch. Although dense weeds are not preferred for grazing animals, that type of habitat is perfect for wintering Short-eared Owls, migrants from the far north. In abundance were numerous rodent species including meadow voles and pocket gophers in addition to wintering birds such as Horned Larks and Lapland Longspurs. Owl food was abundant.
When they are numerous in winters and when food is abundant, migrant Short-eared Owls will sometimes remain to breed in early spring instead of migrating back north. Such was the case in March 2015 when a Chico Short-eared Owl made a scrape on a slightly elevated mound and four chalk-colored eggs were discovered surrounded by anchored tumbleweeds.
Short-eared Owls are found breeding across the U.S. and Canadian Arctic and also found in the southern half of South America, plus in northern Europe and Asia, and they are found on some Pacific islands including Hawaii. Their scientific name, Asio flammeus, means ‘flame-colored owl’ but the reddish or flame coloration is not common in North American Short-ears.
In winter, Short-eared Owls are often found in relatively large numbers where they need extensive prairie or marsh habitats for food and cover. During the winter of 2015, ~12 Short-eared Owls were found on Chico roosting on the ground, often close to one another. In the winters of 2016 and 2017 Short-eared Owls again chose the same large patch of weedy habitat in which to winter but in late November of 2017, only four owls were seen, and by December 2017 only one remained. By January 2018, no owls were detected but the habitat had changed drastically. Only very small amounts of weedy vegetation remained and small sand hills, the original habitat, were again dominant. Food remained abundant as evidenced by the numerous burrows present, but cover in the form of tumbleweeds was no longer available. What was once excellent wintering habitat for Short-eared Owls on Chico Basin Ranch is now open sandy hill country with native grasses, good for grazing but not for wintering, ground-roosting owls.