Archive for the 'Migration' Category

Nov 12 2013

Sparrow Time

Published by under Migration,Songbirds

Fox sparrow and white-throated sparrow (photo by Steve Gosser)

It’s not news that migrating sparrows are back in town but it’s always news to see a fox sparrow in any setting.

Steve Gosser photographed this one (top) with another migrant, a white-throated sparrow, at Harrison Hills Park last week.

Some sparrows come to western Pennsylvania in the fall and stay all winter, including dark-eyed juncoes, American tree sparrows, and the white-throated sparrow shown above.

But fox sparrows are few and far between and right now they’re just passing through, headed for the southern U.S.

If you don’t see one before Thanksgiving you’ll probably have to wait until March to catch them on their return trip back north.

I’ve been looking, but so far no luck.

 

(photo by Steve Gosser)

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Nov 03 2013

Cormorants On The Move

DCCO_drying_sgosserDouble-crested cormorants drying their wings (photo by Steve Gosser)

These double-crested cormorants are drying their wings after diving for fish.  Are they visiting our area?  You bet.

Double-crested cormorants were on the move last week along Lake Erie’s shore.  According to Jerry McWilliam’s waterbird count, 2,125 flew past Presque Isle State Park last Sunday (Oct 27), 227 on Monday, and 680 on Tuesday. Then their numbers dropped.

When cormorants are on the move, the ducks aren’t far behind.

November may be cold but it’s a great month for watching waterfowl.

 

(photo by Steve Gosser)

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Oct 11 2013

Radar Shows Decline

Published by under Migration,Tenth Page

Southern Mississippi Sector weather radar, 9 Oct 2013, 6:38am (image from NOAA)

In one way this is very old news.  In another way it’s sadly up-to-date.

In the early days of radar surveillance, scientists learned that those mysterious blobs on the screen in spring and fall were flocks of night-migrating birds.  In 1965, as part of his graduate study at Louisiana State University, Dr. Sidney A. Gauthreaux, Jr. studied spring migration using radar images at Lake Charles and New Orleans along with his own on-the-ground counts as birds flew past his light beam or the moon.

Twenty years later, the news said that songbirds had declined.  Gauthreaux wondered if this was evident on radar so he collected data from the same two sites and compared the images from good-weather migration nights in 1965-1967 to those in 1987-1989.  In only 20 years he could see that the number of migrating songbirds had declined by 50%.   Half the number of warblers, tanagers, hummingbirds, shorebirds, flycatchers and thrushes made the trip.

That was 24 years ago.  It has only gotten worse.  I don’t know of a recent radar comparison (was there one comparing the 1980′s to 2000′s?) but our ground-based counts show that birds such as the king rail, cerulean warbler and olive-sided flycatcher are in dangerous decline now.  Just last month the eastern red knot was proposed for Endangered Species protection by US Fish and Wildlife.

Meanwhile, it seems ironic that so many people are becoming interested in birds while birds are becoming scarce, but it’s a good thing too.  The more of us that care about birds, the more likely we’ll learn what they need and work to insure their future.

 

(screenshot of NOAA weather radar, 9 Oct 2013, 6:38am EDT. Click on the image to see the current radar page.  Today’s Tenth Page is inspired by page 278 of Ornithology by Frank B. Gill.)

 

p.s.  This NOAA image shows the radar stations that were part of Dr. Gauthreaux’s study.   On Wednesday morning the weather concentrated migrants east of the Mississippi as they approached the Gulf Coast.

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Oct 08 2013

Broad-Wings Pass Veracruz

At Hawk Mountain Sanctuary, this fall’s high count of 1,338 broad-winged hawks flew by the watch on September 20.  That number sounds large but those hawks join all their cohorts from North America to pass a small strip of land between the mountains and the Gulf of Mexico near Veracruz.

The Veracruz Hawk Watch is called the River of Raptors because more than 100,000 hawks per day may pass through between the September 20 and October 25.  During the first two weeks of the watch almost all of them are broad-winged hawks.  On September 23 the broad-wing count at River of Raptors in Cardel was 354,091.

Above, a slideshow video from a 2011 birding trip to Veracruz celebrates the hawk migration and shows the birds and scenery in the area. (Sorry about the ads.)

Below, a very short video shows the “river of raptors.”  A huge kettle of hawks circles up, then tails off in a broad river to the left, heading south.  The Spanish title of this video “Vortex Cambiando a Una Linea Ancha” means “Vortex Switching to a Wide Line.”

Wish I’d been there…

 

(videos from YouTube)

 

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Oct 06 2013

This Is Exciting

Yellow-rumped warbler, October 2013 (photo by Shawn Collins)

They’re here!  The yellow-rumped warblers are back from Canada, on their way to the lower Ohio Valley, the southern U.S., and Central America for the winter.

Yesterday Karyn Delaney and her husband stopped counting at 100 when they found so many yellow-rumps on the Pine Tree Trail at Presque Isle State Park.  Shawn Collins snapped this one in Crawford County.

Like the first snowfall I’m excited to see my first big flock of yellow-rumped warblers in southwestern Pennsylvania.  I haven’t found a flock yet but I think I’ve heard one bird — just one — at Schenley Park.

Unfortunately, just like snow I soon tire of them.  I remember at Magee Marsh last May when my first reaction to seeing yellow-rumped warblers was “Wow!” and within an hour it was “Darn!  Another yellow-rump.”  Their abundance becomes boring.

But I haven’t seen them yet, so for the moment this bird is exciting.

 

(photo by Shawn Collins)

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Sep 26 2013

Thousands Of Blue Jays

Published by under Migration

Blue jay (photo by Charlie Hickey)

There are times when I ask myself, “Where have the blue jays gone?” but this is not one of them.  They’re everywhere right now.

I think of blue jays as year-round residents — and they are through most of their range — but a good number of them migrate.  Their travels, however, are poorly understood because they’re unpredictable.

Some blue jays stay, others go.  Those who leave may be young or old (not just juveniles) and an individual who stayed last winter might leave this year and not the next.  Some don’t bother to come “home” in the spring and are found nesting further south. Others come home to nest but go further south each winter.  The only hint is that blue jays store and eat acorns in the winter so the mast crop may influence their decision to travel.

Blue jays migrate during the day in loose flocks of 10 to 30 birds that often pass by hawk watches. At Cape May, New Jersey, 1,000 to 5,000 blue jays pass by each day from late September through early October.  For the really huge numbers visit Holiday Beach Migration Observatory in Amherstburg, Ontario, 23 miles south of Detroit.

Because jays are reluctant to fly over Lake Erie, they hug the northern shore and funnel past Holiday Beach as they travel southward out of Canada. Typical days in late September and early October see 30,000 to 40,000 blue jays fly by.  The highest count was 264,410 on September 28, 2001.  Observers must have wondered if any blue jays were left in Canada after a day like that!

We never see numbers like this in Pennsylvania though we get a bump up in spring and fall.  Here’s a quick visual from eBird of blue jay population fluctuation in Pennsylvania, years 2009-2013.  Click on the image to see the real graph.

Frequency of Blue Jays in PA, 2009-2013 as of 9/24/2013 (screenshot from eBird)

 

The low point for blue jays in Pennsylvania is late December to early March.

Remind me of this when I ask you where the blue jays are this winter.

(photo by Charlie Hickey. Click on the image to see the original.)

 

p.s. Here are the blue jay record-setting dates from Holiday Beach, Migration Observatory.  Click here for all non-hawk species counts.
Blue Jay Record High Counts:
Sep 26: 1986 = 49,280,  1991 = 59,650
Sep 28: 2001 = 264,410*
Sep 30: 1990 = 51,470, 1993 = 87,000
Oct 1: 2009 = 158,300
Oct 5: 2009 = 152,750

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Sep 25 2013

The Sun Compass

Male monarch butterfly (photo by Marcy Cunkelman)

A week ago I saw my first and only monarch butterfly of 2013.  Their sudden disappearance is both troubling and saddening.  It’s now possible to imagine a world without monarch butterflies.  We are nearly there.

Last winter’s monarch survey in Mexico showed their population was down 59%, a record low.  There have always been population fluctuations but the trend has been running low and lower since 2004.  Scientists believe that agricultural pesticides and herbicides have reduced available poison-free habitat for butterflies (similar to the bees’ problem), so this spring monarch enthusiasts encouraged people to grow safe-haven milkweed for the butterflies.  It wasn’t enough.

Each species has an intrinsic value.  If, or when, the eastern monarch butterfly goes extinct we will lose its pollination contribution, milkweed symbiosis, beauty, and the amazing adaptations that allow multiple generations to migrate from Mexico to Canada and back.

One of the adaptations that will disappear is this:  Monarch butterflies have a sun compass in their antennae.

Their antennae have light sensors that track the amount of light each day.  According to a study in 2009 by Merlin, Gegear and Reppert, this circadian clock “provides the internal timing device that allows the butterflies to correct their flight orientation, relative to skylight parameters, and maintain a southerly flight bearing, as the sun moves across the sky during the day.”  Migratory monarchs without antennae fly in aimless directions.  Monarchs with antennae always orient southwest.

The monarch’s sun compass was discovered only a few years ago.  Now there are almost no monarch butterflies to study.  The world will be a poorer place without them.

Click here for more information on the monarch’s amazing sun compass.

(photo by Marcy Cunkelman, 2008)

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Sep 24 2013

Longest Migration

While songbirds, hawks, and dragonflies are migrating this month there’s a bird whose journey beats them all.

The arctic tern sets long distance records in its pole-to-pole round-trip migration of 44,000 miles (71,000 km).  Since arctic terns can live 30 years, an individual can rack up a lifetime achievement of 1.5 million miles (2.4 million km).

The data behind this amazing feat was published in 2010 by the Arctic Tern Migration Project which studied arctic terns that nest in Greenland and winter in Antarctica.

To track the terns the scientists used tiny geolocator tags from the British Antarctic Survey, the same tags used to track wood thrushes.  In both studies scientists captured each bird, affixed a tag, then had to find the same bird on its breeding grounds a year later and recapture it to gather the data.  Wood thrushes don’t put up a fight but arctic terns relentlessly dive bomb their enemies to drive them away.  This study had bird hazards.

Attacking terns were not the only hazards.  Camping on an island off the coast of Greenland is no picnic.  “Our tents blew out to sea in the storm.”  Yow!

Watch this video from the Encyclopedia of Life to see the terns’ amazing migration and why it’s worthwhile for these birds to travel so far.

 

For more information, visit the Arctic Tern Migration Project at www.arctictern.info.

(video by the Encyclopedia of Life)

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Sep 12 2013

No Food, No Water

Mount Desert Rock (photo by krzdweasel, Creative Commons license)

Twenty miles off the coast of Mount Desert Island is a tiny granite outcrop called Mount Desert Rock.  On a clear day you can see it with binoculars from the mountains of Acadia National Park. It looks like an improbable ship, taller than it is long.

Only 3.5 acres in size, Mount Desert Rock holds three buildings and a lighthouse just 17 feet above sea level. During winter storms and hurricanes the ocean washes over the island and punishes the buildings. The boathouse was swept away during Hurricane Bill in 2009. Isolated and exposed the Rock stands alone. Click here to see how small it is.

Map showing location of Mount Desert Rock (image from Wikimedia Commons)

Whale watching tours from Bar Harbor sometimes circle the Rock.  That’s how I’ve come close but never landed.  The Rock has no harbor so even those authorized to land can only do so when the sea is calm.

Lighthouse keepers and their families used to live year-round on the island, sheltering in the lighthouse during storms.  Since 1998 the College of the Atlantic has had whale and seal study crews posted there on temporary assignment, but they leave before a storm.

No matter who is stationed there, they must survive on food and water shipped from the mainland.  Rainwater is collected in a cistern under the keepers’ house but it’s undrinkable.  Nothing can grow there because the ocean washes away the topsoil in every storm.  And there is noise: The foghorn blares every 30 seconds.

When the weather is right, songbirds take a shortcut across the Gulf of Maine during fall migration from Nova Scotia to Maine.  From the whale watch boat I’ve seen ruby-throated hummingbirds and robins pumping their way past the Rock to Mt. Desert Island 20 miles away.  It’s scary to think they are over open water, sometimes fighting the wind, spending themselves to make landfall on the shores of Acadia — or else they will die.

Fly safe, little birds.  The Rock is no place to rest.  No food.  No water.

(photo by “krzdweasel” via Flickr, Creative Commons license.  Click on the image to see the original. Map from Wikipedia.)

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Sep 11 2013

On The Move

Published by under Migration,Songbirds

Swainson's thrush (photo by Shawn Collins)

Last night in Bath, Maine I heard thrushes migrating in the dark.  As they fly they make short contact calls to keep the flock together. Among the calls, I was able to identify two species.

The first call was plentiful and sounded like the single note of a spring peeper.  Those were Swainson’s thrushes (above).  Click here to hear the peep sound at the beginning of the recording.

The second sound was less frequent.  There were fewer of this species, their call note lasted longer and descended roughly.  By listening at the Macaulay Library online I determined they were gray-cheeked thrushes (below).  Click here to hear.

Gray-cheeked thrush (photo by Shawn Collins)

 

Last night the birds were on the move while the weather was good.  Today will be hot.  Tonight will be stormy.

 

(photos by Shawn Collins)

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