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Posts tagged “Bubo scandiacus

Snowy Owl Gets Mouthful When Hunting In Tall Grass

12-8-17 snowy owl and meadow vole3 049A9802Only Naturally Curious readers would come up with flossing!

If lemmings are in short supply and you’re a Snowy Owl, head for tall grass where small rodents dwell. This juvenile female Snowy Owl successfully caught a Meadow Vole (along with a footful of grass) in its talons and proceeded to swallow the vole whole, along with some of the grass. However, most of the grass remained hanging from the owl’s mouth after the vole had been consumed, so it proceeded to grasp the grass with its foot and pull it out of its mouth (yesterday’s Mystery Photo).

Although many people are under the impression that hard weather forces Snowy Owls farther south some winters, the reason for Snowy Owl invasions or irruptions turns out to be linked to either prey population crashes in the north, high productivity breeding years (producing more predators than the prey can support) or a combination of the two. New research has shown that the abundance of Snowy Owls seen in the eastern U.S. during the winter of 2013-14 was the result of a particularly good nesting season on the Arctic tundra. A population boom of lemmings, the Snowy Owl’s primary food source, translated to a population boom of owls.

 

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The Feathered Feet of Northern Owls

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Most owls have feathered legs, but the feet and toes of some owls, especially those living in colder, higher latitudes, are also densely feathered. The feathers keep the feet of these birds warm, allowing them to hunt where snow is on the ground and temperatures are very low. Great Gray Owls (pictured), Snowy Owls and Northern Hawk Owls are all examples of this phenomenon. Owls living in warmer climes, such as Barn Owls, have sparsely feathered feet and toes, and tropical owls have nearly featherless feet. This variation can also be found within a given species that has a range that extends over many degrees of latitude, such as the Barred Owl.

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Modern Technology Reveals Snowy Owl Winter Behavior

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With the arrival of this winter’s first Snowy Owls in New England comes a renewed interest in the winter ecology of these birds of prey. An organization called Project Snowstorm (www.projectsnowstorm.org ) gathers detailed information every 30 seconds on the movement of Snowy Owls that they have outfitted with a backpack harness containing a solar transmitter. These transmitters use the cellular phone network, not a satellite, and when they are out of range of a cell tower, they store information which is transmitted when the bird is back within cell coverage territory – even if it’s years later.

The information that has been gleaned from this modern technology is stunning, and has allowed us to know far more about the behavior of Snowy Owls in winter. Some Snowy Owls stay within a quarter mile of where they are banded; others cover hundreds of miles within a few weeks. Some Snowy Owls spend much of the winter out on the frozen Great Lakes, where they prey on waterfowl they find in the cracks in the ice that open and close repeatedly.   Not only has it been confirmed that Snowy Owls feed heavily on birds in the winter (especially ducks, geese, grebes and gulls), but their use of channel markers and buoys as hunting perches while they seek prey over the open ocean at night has been documented.

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Snowy Owls Headed North

4-21-14 flying snowy 046The record number of Snowy Owls that spent the winter in New England are turning up in all sorts of new locations now that they are on their way back to their breeding grounds on the open tundra and stopping to refuel along the way. Although many were young birds, and won’t breed this year, the adult owls will when they reach the Arctic in a few weeks. First, the males perform aerial and ground displays. After mating, the female selects a nest site. In addition to having a sufficient food supply, the site must be snow-free, not subject to flooding, and command a view of its surroundings. The latter is achieved by making their nest on a hummock, or slightly raised surface of bare ground. The female scrapes a shallow depression in the earth with her claws, twirling around to make a form-fitted hollow. No insulating material is added to this depression – no vegetation, no feather lining. Eggs and nestlings are totally dependent upon the mother’s warmth, transmitted via the large, featherless, pink patch of skin on her belly known as an “incubation patch.” The female alone incubates the eggs and broods the young chicks while the male provides food for his entire family.

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Snowy Owl Pellet

3-25-14 snowy owl  203Your knowledgeable ID skills regarding yesterday’s Mystery Photo were most impressive!

Snowy Owls are the heaviest owls in North America, weighing roughly 4 pounds (a Great Gray Owl is only 2.4 pounds). A lot of fuel is needed to power this magnificent raptor. In the Arctic, where they live, lemmings are their preferred prey — one owl may eat more than 1,600 of these small rodents in a single year. This winter the Northeast has experienced record numbers of visiting Snowy Owls. A banner year for the Arctic lemming population followed by prolific nesting success for Snowy Owls resulted in an unprecedented “irruption” of these owls further south this winter.

While we do have lemmings in New England, they are uncommon, so Snowy Owls have relied on our small rodent, squirrel, rabbit and hare populations for food. Those owls wintering on the coast, where dunes and moors closely resemble their tundra habitat, have also taken advantage of the large number of sea ducks. As witnessed and described by Nantucket ornithologist Edie Ray, the owls fly up to great heights over the sea, spot waterfowl and then plummet down to just above the surface of the ocean where they sink their talons into a “sitting duck.” As a result, the indigestible bones, teeth and nails of prey are protectively wrapped in feathers as well as fur in the large pellets coughed up by these owls. (Snowy Owl locators: Edie Ray and Sadie Richards; Snowy Owl pellet finder: Sadie Richards)

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