Sunday, November 13, 2011
Short Eared Owl
The short-eared owl has one of the largest distributions of any bird species in the world, being found in prairies, grasslands and other open areas on all continents except Antarctica and Australia.
Although voles are short-eared owls' favorite prey, they will feed on a variety of rodents, shrews, insects and even small birds. Large concentrations of these birds -- known as a "parliament" -- are known to relocate long distances to congregate in areas where there are large rodent populations. How these owls, en masse, discover these rodent population explosions is not known, but this species does wander nomadically in search of better food supplies during years when vole populations are low. They may also form large congregations of hundreds of birds during winter.
Short-eared owls hunt by flying very low over open grassy areas. They locate and capture prey mostly by sound. They hunt mostly at dawn and at dusk, but at different times of the year, short-eared owls can be diurnal or nocturnal as well as crepuscular. Its daytime hunting activities probably coincide with the high-activity periods of voles.
Interestingly, short-eared owls and barn owls, Tyto alba, are often found in similar habitat, and will compete with each other in some areas where they co-occur. We can see this from the see-saw patterns of their populations: when short-eared owl populations increase, barn owl populations decline and vice-versa.
Here's a video of a short-eared owl hunting in the late afternoon. This film gives you an idea of how these owls fly, the habitat they are found in, how they cache freshly-killed prey, and it also gives you a quick look at one bird's short "ears", which are invisible from a distance.