DELMARVA ALMANAC

Delmarva’s Snowy Owls

by Jim Rapp

Learn about one of our most charismatic winter visitors, the Snowy Owl.

Since the first of January, Delmarva birders have been treated to a number of birds that are unusual for our region. These rarities include a Vermillion Flycatcher and Loggerhead Shrike in Maryland's Kent County, a Franklin's Gull in Dorchester County, and Eurasian Wigeons in both Sussex and Accomack Counties.

For hardcore birders, this is pretty exciting stuff, and reason enough to bundle up in outdoor gear, pack the optics and head out into the field. Less enthusiastic types may not feel compelled to brave the winter weather for rare gulls and ducks.

But - there's one bird that makes even the wimpiest wildlife watcher don the hat, scarf and gloves, grab the binoculars, and travel through Arctic conditions for a just a glimpse at brilliant white feathers and big golden eyes. Even folks who would never identify as "a birder" are known to trek after these rare Northern visitors, perhaps because of the popularity of Harry Potter's pet, Hedwig.

The magnificent Snowy Owl spends summers far north of Delmarva in the Arctic Circle, but migrates south in the winter. Commonly seen in the northern U.S., this time of year, Snowies sometimes venture to Delmarva's open spaces. During dramatic migrations known as "irruptions," some Snowy Owls invade the U.S. as far south as Florida.

Snowy Owls are the largest owl by weight in North America. They have snowy white feathers with differing degrees of brownish-black flecks and bars. The close flecking on females can give them a salt & pepper appearance. Immature males also have dense flecks and bars, but mature male Snowy Owls range from pale to pure, ghostly white.

Both sexes have smooth, round heads that lack the ear tufts found on Great Horned Owls and Screech Owls. They have chunky bodies and substantial feathering on their legs. Their intense yellow eyes are outlined in black.

In the Arctic, Snowy Owls hunt for lemmings, ptarmigans, waterfowl, and other small mammals and birds. Unlike their nocturnal relatives, Snowy Owls hunt during the day. In the Arctic summer, daylight lasts for 24 hours, and the owls will hunt around the clock. When hunting, they use their excellent binocular vision and hearing to locate their prey, even under thick vegetation or a blanket of snow. Once the prey is in focus, the owls fly, and sometimes run, to pounce with their powerful talons.

Snowy Owls are not forest birds. They prefer the vast, open tundra, where they spend most of their time sitting on slightly elevated hills, surveying the terrain for prey. Female Snowies build their nests here, too, by scraping a shallow depression on the ground. Clutch size depends upon food availability, and can range from 3 to 11 eggs.

The female incubates the eggs, and the male brings food to mother and babies. Young Snowies leave the nest around 25 days after hatching, but they can't fly well until they're a month and a half old. After they are old enough to be on their own, the young owls disperse in all directions from their nest. Scientists tracked young owls leaving one nest on Victoria Island in the Canadian Arctic, and found that one owl went to the Hudson Bay, one to southeastern Ontario, and one flew all the way to eastern Russia.

Some Snowy Owls may stay on their Arctic breeding grounds throughout the year, while others migrate to winter in southern Canada and the northern United States. Snowies are common winter visitors around the Great Lakes and in New England.

This is Jim Rapp and you're listening to the Delmarva Almanac. We're talking about Snowy Owls.

During an irruption year -- that's irruption with an "I" rather then an "E" -- Snowy Owl migrations are all over the place. During a massive irruption over the winter that started in late 2013, Snowy Owls made it as far south as Vicksburg, Mississippi and Jacksonville, Florida. One bird pushed all the way out to the island of Bermuda, 640 miles from the mainland U.S. in the Atlantic Ocean.

That was a wild winter for birders on Delmarva! We had Snowy Owls in Cape Charles and Chincoteague, Crisfield and Kent Island, and Lewes and Dover. On the Peninsula, the birds definitely prefer the coastal habitats of our barrier islands and Delaware Bayshore and our low Chesapeake marshes, but they did make forays into Salisbury and Centreville. Our flat coastlines and dunes probably remind them of their summer homes on the Arctic tundra.

That doesn't mean that you won't find them perched on tall trees, telephone poles or buildings. Recently, a Snowy Owl has been seen and photographed on the roof of a condominium just north of the Kent Narrows Bridge in Queen Anne's County.

2016 has started slow for Snowy Owl sightings. In addition to the Kent Narrows bird, another Snowy was seen near Rumbly in Somerset County just after the New Year.

Snowy Owl irruptions are unpredictable. We're really don't know the reason why some years are bigger than others, but we do know it's mostly about food and babies.

The former assumption was that hungry owls migrate south when food becomes scarce in the north. It was also assumed that many irruption year Snowy Owls did not survive their long migrations or winters in the Southern U.S.

Neither assumption is correct. In a strange twist, it's actually an abundance of food, particularly those plump, tasty lemmings, that is linked to Snowy Owl irruptions. Lots of prey leads to large numbers of eggs being laid, and high survival rates for the baby owls. After a bountiful nesting season, many of the young owls fly south.

While they are here on Delmarva and beyond, the visiting Snowies seem to thrive. Researchers have discovered that Snowy Owls in irruption years tend to be fat and happy, sometimes more so than owls studied in non-irruption years.

Without lemmings and ptarmigans, what do Snowy Owls eat while they winter on Delmarva? Thanks to owls outfitted with backpack transmitters with GPS satellite technology, researchers have learned that Snowy Owls along the Delmarva coast spend a lot of time hunting offshore at night. The owls are likely feeding on wintering populations of ducks, particularly scoters that sleep in large flocks on the water. The incredible accuracy of the GPS transmitters has shown that coastal Snowy Owls often use channel markers and buoys as perches for their duck hunting.

During the mega-irruption that started in late 2013, scientists were able to tag 22 Snowy Owls with GPS transmitter backpacks. Using this amazing technology, owl movements can be tracked in fine detail and for multiple migrations. You can learn more about Snowy Owl migrations and follow the tagged Snowy Owls, including some tagged here on Delmarva, at www.ProjectSnowstorm.org.

We don't yet know if this recent blast of cold winter weather will bring more Snowy Owls to the Peninsula, but if it does, you can join the expert guides leading field trips to look for Snowies during the Delmarva Winter Birding Weekend, which will be held January 29 through 31. For more information, please visit http://www.DelmarvaBirding.com.

Read the article or watch our 2014 interview with Ocean City Photographer Allen Sklar.

Visit these links to find out more about Snowy Owls.
https://www.allaboutbirds.org/guide/Snowy_Owl/id
http://www.projectsnowstorm.org
http://news.maryland.gov/dnr/2014/12/11/rehabilitated-snowy-owl-released-at-assateague-state-park/
http://www.delmarvalife.com/delmarvalife/trending/chesapeake-bay-environmental-center-puts-out-snowy-owl-alert/