Flight of the Hunter

SCI­EN­TISTS ARE RAC­ING TO DIS­COVER WHY THE SNOWY OWL, AN AN­CIENT ICON OF THE ARC­TIC, IS DIS­AP­PEAR­ING BE­FORE OUR EYES

Smithsonian Magazine - - Con­tents - By Leigh Calvez

With its ghost­like plumage and yel­low eyes, the snowy owl is one of the Far North’s most cap­ti­vat­ing crea­tures. Now sci­en­tists say it’s dis­ap­pear­ing—and they’re not sure why

AWHITE GLOW AGAINST THE BROWN SUM­MER tun­dra caught my eye. Through binoc­u­lars, I could see it was a male snowy owl. His body was cov­ered in thick, white down, off­set by a black beak, black talons and a few black dots on his feath­ers. His head swiveled from side to side as his for­ward-fac­ing yel­low eyes watched for any rustling of prey.

The snowy owl, like the po­lar bear, holds a spe­cial place in hu­man imag­i­na­tion, from an­cient moral­ity tales told around Arc­tic fires to Hed­wig from the wiz­ard­ing world of Harry Pot­ter. Th­ese north­ern wan­der­ers can be found in Canada, Scan­di­navia, Rus­sia, Ice­land and the British Isles—oc­ca­sion­ally even mak­ing it as far south as Hawaii. They can fly back and forth across con­ti­nents. One fe­male owl tracked in 2012 trav­eled 7,000 miles round-trip from Bos­ton to Nu­navut. In a phe­nom­e­non known as an ir­rup­tion, large num­bers of snowy owls some­times emerge from their nests in a given sea­son and make it down to the sub­urbs of U.S. cities like Seat­tle and Bos­ton—even as far south as Texas.

SNOWY OWLS, ONCE A FEA­TURE OF THE FAR NORTH AS RE­LI­ABLE AS ICE, ARE BE­COM­ING LESS AND LESS COM­MON.

Like ice, th­ese long­time icons of the Far North are be­com­ing less and less com­mon. In the most re­cent Red List of Threat­ened Species, pub­lished last De­cem­ber, the In­ter­na­tional Union for Con­ser­va­tion of Na­ture (IUCN) listed the snowy owl’s sta­tus, for the first time, as “vul­ner­a­ble,” after re­search showed that the adult pop­u­la­tion had de­creased to 28,000, down from 200,000 in 2013. The IUCN cau­tioned that if the rate of de­cline “proves to be even higher, the species may be el­i­gi­ble for fur­ther up­list­ing to ‘en­dan­gered.’ ”

Den­ver Holt, the founder and pres­i­dent of the non­profit Owl Re­search In­sti­tute (ORI) and one of the na­tion’s pre-em­i­nent owl bi­ol­o­gists, has long been doc­u­ment­ing th­ese signs of trou­ble. For more than two decades, he’s been trav­el­ing to Utqi­agvik (for­merly Bar­row), Alaska, the north­ern­most town in the United States and one of the snowy owl’s top breed­ing grounds. In 1995, Holt counted 54 snowy owl nests. In 2006, there were 38. This year, he found only seven, and three of those nests failed.

Owls do not build nests like other birds do. In­stead, a fe­male snowy—larger and darker than her male coun­ter­part—scratches out a shal­low bowl in the earth, usu­ally atop a small hill. Watch­ing for preda­tors,

ONE RISK LEM­MINGS DON’T FACE IS SUI­CI­DALLY FOL­LOW­ING EACH OTHER OFF CLIFFS. THAT MYTH COMES FROM A 1958 DIS­NEY DOC­U­MEN­TARY.

she lays one egg about ev­ery two days. Al­to­gether, she may lay around a dozen, de­pend­ing on food avail­abil­ity. “Brown lem­mings are the bot­tom line for snowy owls here,” says Holt. Males bring home the lem­mings, and fe­males stack them around the nest­ing site in caches as large as 10 or 15.

Though snowy owls will eat voles, arc­tic hares and smaller birds, a study by the

Owl Re­search In­sti­tute showed that out of 43,000 prey an­i­mals col­lected at snowy owl breed­ing sites, 90 per­cent were lem­mings. Th­ese small, mouse­like ro­dents stay ac­tive all win­ter long, eat­ing moss when there are no green leaves avail­able. Every­thing has to be just right for them to flour­ish. Too much snowmelt too early in the sea­son and the lem­mings are forced to spend more time above­ground, mak­ing them sus­cep­ti­ble to ev­ery preda­tor in the area. Too lit­tle snowmelt and there isn’t enough vege­ta­tion for the lem­mings to eat. (One risk lem­mings don’t face is sui­ci­dally fol­low­ing each other off cliffs. That myth comes from a 1958 Dis­ney doc­u­men­tary, White Wilder­ness, in which film­mak­ers herded a group of lem­mings off a cliff to cre­ate a dra­matic scene.) Snowy owls need as much as a pound of prey ev­ery day to sur­vive the harsh arc­tic con­di­tions, and catch­ing lem­mings is more ef­fi­cient than hunt­ing seabirds.

Lem­ming num­bers are thought to go through three- to four-year boom and bust cy­cles. Some sci­en­tists be­lieve snowy owls and other preda­tors—such as stoats and foxes—drive th­ese trends. When lem­mings are plen­ti­ful, the crea­tures who eat them flour­ish. When lem­mings dis­ap­pear, their preda­tors’ num­bers also shrink, al­low­ing lem­ming num­bers to climb. Once there are more lem­mings on the ground again, snowy owl pop­u­la­tions rise ac­cord­ingly.

But Holt doesn’t be­lieve it’s that sim­ple: “It’s a pop­u­la­tion fluc­tu­a­tion and every­thing has to be in line for a boom. But it’s not a cy­cle.” And the over­all num­bers are clearly trend­ing down. In Novem­ber 2017, ORI was awarded a grant to de­ter­mine if cli­mate change is caus­ing the de­cline. ORI will draw on its own 27 years of snowy owl and lem­ming data, along with weather data col­lected by the Na­tional Weather Ser­vice and the Bar­row Ob­ser­va­tory.

As Holt hunts for an­swers, he re­mains awed by the strange­ness of the bird it­self. “There is some­thing about that huge white owl, adapted to arc­tic en­vi­ron­ments, that lures me,” says Holt. “It’s sim­i­lar to look­ing at fresh snow. There’s some­thing spe­cial, un­usual or mag­i­cal. I just en­joy see­ing them, and it may not be tan­gi­ble.”

AS HOLT HUNTS FOR AN­SWERS, HE RE­MAINS AWED BY THE STRANGE­NESS OF THE BIRD IT­SELF.

Left: Den­ver Holt ducks near a nest to avoid be­ing at­tacked by a pro­tec­tive fa­ther. Right: Holt holds a 23-day-oldchick he found out­side its nest.

Snowy owl chicks hatch from their shells about a month afterthe eggs were first laid on the ground.

Newspapers in English

Newspapers from USA

© PressReader. All rights reserved.