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The Snowy Owl Irruption of 2013
by Pete Dunne

 

 (Photos: Susan Hill)

The Snowy Owl is a large, nomadic and primarily Arctic raptor.  Its breeding range is circumpolar and population density and distribution during both the breeding and non-breeding season vary year to year.  The owls breed mostly coastally where and when populations of brown lemmings reach their numeric peak.  The distribution of lemmings is not uniform but concentrated spatially and temporally, so breeding owls seeking good lemming concentrations must move from place to place and year to year.

The result is that Snowy Owls may be a common breeder one year and absent from this same location the next. This strategy is used by other Arctic predators including Rough-legged Hawk and Pomarine Jaeger.  Population fluctuations also characterize Snowy Owl’s distribution in winter.  After the breeding season most Snowy Owls vacate breeding areas and relocate to habitats which offer prey and hunting conditions suited for an Arctic bird of open, unforested regions.   

Some birds, including numbers of adult males, elect to winter in the Canadian prairie provinces every year.  Others, mostly adult females, fly north onto the ice cap after nesting, concentrating near open leads of water that support wintering alcids and sea ducks.  A few birds, mostly juveniles, range south across the northern United States every year (average 0-3 in New Jersey) but every few years, more than the usual small number journey south and every few decades northern states are subject to major irruptions during which hundreds of these Arctic owls may winter south of their normal winter range.  This is one such bonus year.    The last major eruption to occur in New Jersey was the winter of 1926-27.  The most recent before that was way back in 1890-91.  During these events hundreds of owls were shot–mostly as trophies.  Snowy Owls have since been granted state and federal protection and shooting the birds today is illegal. 

Whether this year’s influx of owls will measure up to the standards of historic benchmark years is yet to be established.  Owls which begin searching for winter quarters in November will continue to wander in search of suitable winter quarters through January. 

So even though the New York region is experiencing a greater than average influx of birds this year—the greatest Snowy Owl incursion in a human generation—the full scale of the influx  is yet unknown.  As of mid-December approximately 29 birds had been sighted in New Jersey, most of them coastal, ranging from Sandy Hook in lower New York Bay to Stone Harbor.   Sightings have also occurred along Delaware Bay and the Delaware River.

See our Press Release:  Airports and Owls - The NJ Audubon View

Looking more broadly, this year’s incursion seems particularly widespread, extending to the Great Lakes and the Pacific Northwest.  Snowy Owls found in Bermuda and Hawaii also underscore the broad-based nature of the 2013 irruption.  However sources abroad advise that the irruption is not reflected in Europe, undermining speculation that this year’s mass movement is somehow linked to changes to the Arctic environment.

These large cyclic flights of owls occurred before global warming was an issue and while they may well relate to a scarcity of prey or unsuitable foraging conditions in more northern parts of the bird’s typical winter range, it seems that the factors that trigger Snowy Owl irruptions are historic and episodic, not linked to recent environmental changes.  Having said this there is no reason not to conclude that this year’s irruption is not tied at least in part to a very successful breeding season fueled by a surfeit of prey (primarily lemmings) in the Arctic.  There are also no grounds to presume that changes to the Arctic environment resulting from global warming will not ultimately affect Snowy Owls in time.   One thing that seems not to be true is the Snowy Owls presumed dependence upon lemmings in winter.  For many years it was believed that these large migratory irruptions of Snowy Owls were the result of a crash in the Arctic lemming population.  Snowy Owls seem far from dependent upon lemmings with many birds electing to winter in areas where lemmings are not found–e.g. the Canadian prairies and Arctic ice sheet.  If lemming numbers were key to the bird’s survival it would make sense that a nomadic owl would simply migrate several hundred miles to the nearest patch of tundra offering high lemming density rather than migrate a thousand miles in search of alternative prey.    

Speculations notwithstanding, there is no reason not to appreciate this year’s owl flight for what it is, the largest incursion of these impressive birds in a human generation.  Wintering primarily in coastal locations–e.g. beaches and salt marshes—Snowy Owls resemble soot-flecked two foot tall snowmen, and they are commonly seen sitting on some elevated perch or dune.  Young birds which constitute most of the Snowy Owls traveling this far south may be so heavily marked they look overall blackish.  Only adult male birds are wholly white and these are rarely, if ever, seen in New Jersey.

To observe Snowy Owls you are best advised to join a New Jersey Audubon field trip led by experts who know how and where to look and who are equipped with high quality spotting scopes that nullify distance.  If you plan on looking on your own, Click Here for "Tips for Finding Snowy Owls."  Snowy Owls, like all wildlife, need and deserve privacy.  Because the birds are active in daylight, perch in the open, and remain immobile for long periods unless disturbed, use binoculars and conduct your observations from a comfortable distance.  Flushing birds forces them to waste energy and draws the attention of gulls, crows and hawks who may harass the owl when all it wants is to be left in peace.  If the bird becomes restless it is telling you that you are too close.  Pressing birds for a better view or a better photo is considered irresponsible behavior.

For field trip information,
go to the New Jersey Audubon
Calendar of Events or New Jersey eBird.  

The owls will remain in our region until March or April then return to the Arctic.  Good places to see Snowy Owls include Brigantine National Wildlife Refuge.  Check the bird sighting sheet in the visitor center for recent sightings.  Other birds to watch for include Bald and Golden Eagles, Rough-legged Hawk, Northern Harrier, Short-eared Owl, Brant, Snow Geese, Long-tailed Duck and many other waterfowl species.  Binoculars are almost essential.  New Jersey Audubon has multiple trips to Brigantine (aka Forsythe NWR) throughout the year; go to New Jersey eBird on the New Jersey Audubon website for details about these and other winter excursions in search of Snowy Owls.

Special Note:  New Jersey Audubon recognizes our state’s connection with the Arctic in the current Snowy Owl incursion, as well as the scores of bird species currently in New Jersey’s coastal regions where the marshes, beaches and near shore waters are teeming with tens of thousands of songbirds, waterfowl and shorebirds that breed in the Arctic and spend the balance of their lives in New Jersey.   The many thousands of Snow Geese, Red-throated Loons, Snow Buntings and even American Robins in New Jersey now were breeding in the Arctic this summer. 

Recognizing our state’s link to this tremendously productive ecosystem and the need to preserve it and other Refuges, New Jersey Congressman LoBiondo added his cosponsorship to the Udall-Eisenhower Arctic Wilderness Act (H.R. 139) on December 5th, which would designate the Arctic National Wildlife Refuge’s coastal plain as Wilderness.  The 1.5 million acre coastal plain is the biological heart of the Arctic Refuge and home to nearly 200 species of birds, many of which pass through New Jersey when migrating to or from the Arctic Refuge, as well as many that spend the non-breeding season in the state.  New Jersey Audubon commends Congressman Frank LoBiondo for his tremendous conservation leadership and will continue to seek a broad base of support for the Arctic Refuge, which contains more abundant and diverse wildlife than any protected area in the circumpolar north.  

Pete Dunne, CCO/NJ Audubon