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Birds migrate on aerial highways
Article by:VAL CUNNINGHAM
Contributing Writer SEP 1 R 2014
September 16,2014-1:10 PM
Wien things go as they should in the natural world,following
cycles set down ages ago,we tend to take them for granted,not
giving much thought to the wonders around us.
Take the migration of birds:It may start subtly,without our noticing
Millions of wag beats will del th!s eastern kingbird to
that the back-yard catbird is no longer calling or that orioles haven't sc:rh Amenca to spend the winter feast.ng on insects.
been seen for some weeks.Robins,so visible in summer,either Don Severson,
become an unusual sight or show up in flocks.
Swallows gather on utility lines,chattering noisily between great
sweeping flight forays,and bluebird families fly overhead,singing
their soft songs to stay in touch.
Fall migration clears forests,meadows,parks,lakes and marshes
of all but the resident birds.Billions of them are already heading
southward,or are getting ready to go.
About two-thirds of the birds that spend the warm seasons here
will be gone by late fall,including thrushes,grosbeaks,most
raptors,wading birds,shorebirds,hummingbirds and swifts.Some,
like the chestnut-sided warbler and the rest of its clan,will travel
long distances before setting down in the tropics for the winter.
(We saw some of these handsome little birds in Cuba in March.)
Others,like robins,may travel only a few hundred miles,to warmer 13 '` aae*latr e :rth fs a gr e,p,ac t'vieu,
states where fruit is abundant.
Star?rib!.'-tile.
(Robins do their best to confuse us,because they are migratory,
but some from farther north may settle in our area for the winter,making it seem as if they've stayed around all year.
Goldfinches and blue jays are known to do this,too,with those heading south being replaced by more northerly birds,until
the populations switch back in the spring.)
Credit is due
Birds may make it look easy,but migration is full of dangers and uncertainty.For example,fall migration peaks at prime
hurricane season,when many birds need to cross the Gulf of Mexico.Think of tiny hummingbirds with feet gripped tightly on
shrubs lashing in the wind as they wait to make the 500-mile crossing.
Or habitat disappears—think of vireos accustomed to stopping over for a few days in a Mexican woodland,only to find it
replaced by vacation homes since their last trip.There are other dangers,too:Consider a flock of bobolinks,eager for a meal
to replace calories lost in a long flight,settling down in a rice field,with no way to sense whether it has been poisoned with
agrochemicals.
And still birds make the journey,twice a year,for as long as they live.
Not that these travelers have much choice,since the urge to migrate is built into their DNA.It's part of their survival
repertoire,honed over thousands of years,to cope with the biggest threat of all.Many of us think birds leave to escape
winter's cold,but the real driver is food scarcity in the cold months.Migration is the only sure way for the majority of birds to
continue to enjoy an abundant supply of insects,or berries or fish,whatever makes up their daily dietary regime.
Night or day
Some birds may travel as little as 15 miles on a given day,pausing frequently to rest and forage,while others fly hundreds of
miles.
Depending on the distance of their final destination,some birds travel for a few weeks,while others may be"on the road"for
up to four months.They're in less of a hurry in the fall,since they aren't on the way to compete for the best breeding
territories.
Birds that are fast fliers and those that rely on catching insects on their joumey,such as swallows and kingbirds,fly during
the daytime.So do ducks and loons,and raptors that soar on rising columns of sunlight-warmed air.Smaller birds fly during
the night to avoid raptors and exploit the calmer air.
Birds lift off from their summer homes or staging areas where they gather to get ready.Guided by major geographical
landmarks,such as the coasts,mountain ranges and major rivers,birds tend to move in great linear waves along aerial
highways we call flyways.
Billions head out,but not all of them return.Fewer than 30 percent of young songbirds survive their first year,and the
hazards of migration are a major reason.
Migration occurs year after year,but it's still worthy of our notice—and our awe.Billions of tiny beings fling themselves into
the skies,without regard for hazard or danger,an ounce or two of sheer energy facing whatever comes their way.
http://www.startribune.com/printarticle/?id=275320751 9/18/2014
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St.Paul resident Val Cunningham,who volunteers with the St.Paul Audubon Society and writes about nature for local,
regional and national newspapers and magazines,can be reached at val writes @comcast.net.
More on migration
Duluth's'hot spot'
One of the best places to view fall migration is only 2'%hours north of the Twin Cities,at Duluth's Hawk Ridge.If wind and
weather are right,thousands of hawks,eagles and songbirds may stream by the ridge,some even at eye level.Best viewing
times are 10 a.m.to 2 p.m.each day.There are no guarantees,since some days only a few hawks or eagles may migrate
past the ridge.But you may get lucky and visit on a day when the skies are filled with kettles,rising swirls of hundreds or
thousands of raptors.Check out the ridge's website,www.hawkridge.org,for more information.
Migration close to home
Parks along the Mississippi River(Lilydale,Crosby Farm,Hidden Falls,Minnehaha Falls)can be worth a visit in early
morning or early evening to observe migrants as they drop down after a long night of flying or head out on another leg of their
journey.
You might also visit Wood Lake Nature Center in Richfield,Springbrook Nature Center in Fridley,Carpenter Nature Center in
Hastings or Maplewood Nature Center in Maplewood to watch for migrants.
And don't forget your own back yard:So many birds are on the move that a few will almost surely drop down to check for
food or a drink at some point.(Keep feeders filled and birdbaths fresh.)
02014 Star Tribune
http://www.startribune.com/printarticle/?id=275320751 9/18/2014