Archive for the 'Migration' Category

Jun 26 2013

I’m On A Tight Schedule

Published by under Migration,Peregrines

Island Girl, 2009 (photo by Bud Anderson from the Southern Cross Research Project)

Late June is an intensely busy time for peregrine parents in North America’s mid latitudes. If their nests were successful they have young about to fledge or already on the wing who must become independent in just four to eight weeks.

If you think that’s fast, consider the life of an arctic peregrine.

Island Girl, pictured above, is an arctic peregrine tagged with a satellite transmitter in southern Chile in 2009 by the Falcon Research Group. They’ve tracked her migrations every year in amazing detail, able to determine latitude, longitude and altitude of her roosts and see the neighborhood where she chooses to sleep via Google Earth.

Island Girl nests on Baffin Island, Canada and spends November to April on the coast of southern Chile. To do this she travels nearly 17,000 miles per year.  This spring she left Chile on April 17 and arrived at her eyrie in Canada on June 3, covering 8,868 miles in only 48 days. She got home early.

Here’s a screenshot of her trip.  (Click on it to see the real map.)  This is the feat of an athlete!
Screen shot of Island Girl's migration tracking map, Spring 2013 (from Southern Cross Peregrine Project)

Now that she’s on her breeding grounds Island Girl has a very compressed schedule. She arrived on June 3 (the day Silver Boy fledged) and absolutely must leave in late September.  Winter comes quickly on Baffin Island so Island Girl always leaves between September 20 and 24.  Always.

This gives her about 111 days to court, lay eggs, incubate, raise nestlings, and teach fledglings.

Her schedule probably looks like this:

  • Courtship and egg laying:  14-18 days, June 3 to June 19.  This is the most optimistic schedule, assuming an established mate, an established territory and no intruders.
  • Incubation: 33-35 days, June 19 to July 23
  • Nestling phase, 39 to 45 days, July 23 to September 3
  • Fledged young dependent on parents, 4-8 weeks,  September 3 to October 1 or October 29.

There’s barely time to fledge young and begin to teach them before she has to leave for Chile. In fact her kids might leave with her and learn to hunt while traveling.

Arctic peregrines are certainly on a tight schedule!

 

(Island Girl photo by Bud Anderson and Spring 2013 migration tracking map from the Southern Cross Peregrine Project, Falcon Research Group Click on the images to see the originals)

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May 16 2013

A Two Week Trip

Wood Thrush (photo by Steve Gosser)

I heard my first wood thrush this year in Schenley Park on April 24 but the real influx didn’t occur until May 8.  On that morning the wood thrush population in the park doubled overnight.

Each bird made the trip from eastern Honduras or Nicaragua in 13-15 days.  We know where they spend the winter, how long it takes to get here, and the routes individual birds take thanks to ongoing migration studies by Bridget Stutchbury’s University of York team, begun in 2007.

Stutchbury pioneered the use of tiny geolocators, smaller than a penny, that record only two things: the universal date-time (UTC) and the amount of light.  Crunch a year of data and you get sunrise, sunset and day length which reveal the bird’s location each day.  To collect this data, the tagged bird had to return from migration (a 60% chance) and be re-trapped to remove the geolocator (90% success rate, skill required!).

Now that the team has tracked some individual wood thrushes for several years they’ve found that:

  • Wood thrushes fly more than 300 miles a day on migration.
  • In the fall, they may stopover in the southern U.S. or the Yucatan for one to four weeks before proceeding to their final destination.
  • They dawdle in the fall but return two to six times faster in the spring because they barely stop at all.
  • Wood thrushes who live near each other in Pennsylvania don’t scatter when they get to Central America.  A single breeding population from Pennsylvania spends the winter in a narrow band of forest in eastern Honduras and Nicaragua.  If that forest disappears, so will all those wood thrushes.
  • Wood thrushes don’t use local weather cues to determine when to head north.  Instead they have built in endogenous triggers similar to long-distance shorebirds.  Some of their triggers are so accurate that individuals begin northward migration on the same day every year.
  • Though wood thrushes tend to have a favorite departure date they don’t take the same route every year.  The route depends on weather and fitness.
  • First year birds tend to leave the wintering grounds later than those who’ve made the trip before.

So I’ll bet those early wood thrushes are the older, experienced birds who left Central America around April 10.  Two weeks and more than 2,000 miles later they arrived in my neighborhood on the day the rest of the flock left the wintering grounds.

Awesome!

 

For more on these studies, click here for background on the 2010 report and here for their 2012 findings.

(photo by Steve Gosser)

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May 07 2013

Important Rest Stops

Published by under Migration

Bay-breasted Warbler (photo by Chuck Tague)

Birders flock to Magee Marsh, Ohio in May because the birds do, too.  For us it’s exciting to see them so close. For them it’s an important rest stop on their long journey from Central or South America to Canada.

Songbirds migrate overnight and stop before dawn to rest for the day. They may be leisurely in the fall but they make the journey faster in spring.  This bay-breasted warbler travels from Panama or northern South America to Canada, a journey of at least 2,400 miles, and he does it in as little as 17 days.  His longest leg is more than 500 miles non-stop across the Gulf of Mexico.

Rest stops are key.

Imagine you’re driving each night on a long distance journey.  From experience, or because you’re traveling in a group (i.e. flock), you’ve picked the rest stops in advance.  You’re on a tight schedule and you’re not going to stop often.  A few of the rest stops are the last food and fuel for hundreds of miles.  No problem.  You’ve been there before and you know those places are good.

But what if you arrive one night and a crucial rest stop is gone… destroyed?  No gasoline, no food and you’re nearly out of both.   You have no idea where to find a substitute and you’re already tired.  If you’re a bird, this emergency can kill you.

That’s why the warblers at Magee Marsh don’t seem to care about people. They’re hungry and they don’t have much time.  They’re fueling up so they can leave tonight for Canada.

And that’s why the National Audubon Society, the American Bird Conservancy, the Nature Conservancy, and the Western Hemisphere Shorebird Reserve Network  are all working to preserve stopover sites for migratory birds.

 

(photo by Chuck Tague)

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May 05 2013

On Erie’s Southern Shore

Published by under Migration,Songbirds

Cape May warbler (photo by Bobby Greene)

Cape May warblers are some of the many wonderful birds at Magee Marsh, Ohio this year.

Other highlights on the south shore of Lake Erie include:

  • An eye level look at a cerulean warbler,
  • Discovering that a brown lump in a field was an American golden-plover when he turned around,
  • Finding two soras in the reeds … and then they mated,
  • Seeing a great horned owl nestling with pretty face feathers,
  • And watching a sora cross the road. He made himself into a ball so he looked like a very slow, round muskrat without a tail (was this camouflage?) and risked his life by walking slowly in front of traffic.  Fortunately all the drivers were birders and we stopped to stare and spare his life.

Glad to be here!

(photo by Bobby Greene)

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Apr 07 2013

Major Migration In The Ohio Valley

Published by under Migration

NWS Central Great Lakes radar, 4/7/13, 4:18am (image from the National Weather Service)

The wind was finally from the south overnight.  This morning’s pre-dawn weather radar shows a little rain and a lot of birds.

The blue circles over the cities are radar locations picking up lots of small bodies flying north.  Yes, birds!

If you live in any of these blue circle zones, today would be a great day to go birding — unless it’s storming.

p.s.  There was not a lot of migration activity on the East Coast.  Their wind was probably unfavorable.

(radar image from the National Weather Service Central Great Lakes. Click on the image to see the most recent view.)

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Mar 27 2013

Sniffing Their Way North

Gray Catbird (photo by Alan Vernon from Wikimedia)

Conventional wisdom says that birds can’t smell anything, but this isn’t so.

Did you know they use their sense of smell to guide them on migration and that it’s more important for navigation than magnetic field detection?

Back in 2009 the Max Planck Institute of Ornithology ran an experiment to see which mattered  more.  During fall migration they captured 67 gray catbirds and put tiny radio transmitters on them.  48 were captured at the Princeton field station, 19 were captured in Illinois and delivered overnight to New Jersey.  This presented the Illinois birds with a big navigational challenge.

All of the birds were fitted with tiny radio transmitters and divided into three groups.  One third had scramblers to impair their magnetic field sense, one-third had a temporarily impaired sense of smell, one third had no impairments.

When released to continue their migration, where did the birds go?

The juvenile birds performed as expected.  Having never made the trip before they had no mental map so they flew due south to Cape May and had to cross Delaware Bay at its widest point.

Unimpaired adults and those with an impaired magnetic sense used their mental maps and sense of smell to fly southwest and avoid Delaware Bay.  Even the “blown off course” Illinois birds flew west or southwest to correct for their new location.

But those who couldn’t smell anything were a little lost.  The adults with mental maps fell back on their original inborn guidance system and flew due south.  So, yes, their sense of smell matters a lot more than we expected.

Next month gray catbirds will arrive in Pittsburgh from their winter range in Florida, Cuba and the lands surrounding the Gulf of Mexico.  When they get here, you can be sure they sniffed their way north.

I wonder what they’re smelling…

 

(photo by Alan Vernon from Wikimedia Commons.  Click on the image to see the original)

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Feb 19 2013

Robin Hiatus

Published by under Migration,Songbirds

AAmerican Robin (photo by Chuck Tague)

Have you noticed?  There aren’t many robins in Pittsburgh right now.

In December it was another story.  Every day I watched hundreds feast on the ornamental fruit trees in Oakland.  Their numbers fell slightly in early January, then surged again on the 13th when I saw so many that I recorded their number as (infinity) in my notebook.

But they ate all the fruit and the ground was too frozen to find worms and invertebrates, so they left. If I’m lucky I see one or two robins a day.

This situation is only temporary. The robins wintering in Florida are getting restless. Soon they’ll come north, following the 37oF average daily temperature isotherm and the arrival of the Spring.

You can watch their progress and contribute your own observations on the Journey North website.  Click here to see an animated map of the Robin Wave.

We’re in a robin hiatus now but they’ll be back soon.  My prediction is March 5.  What do you think?

(photo by Chuck Tague)

15 responses so far

Jan 15 2013

Look Closely

Published by under Migration,Songbirds

If you merely glanced at this feeder from afar, you might assume all the birds are goldfinches.

They’re all the same size, but the two birds at the top are common redpolls, the latest arrivals in a massive irruption of winter birds.

In western Pennsylvania they’ve joined purple finches, red and white-winged crossbills, pine siskins, evening grosbeaks, and red-breasted nuthatches, all of whom came south because of the drought up north.

I’ve chronicled other irruptions (see list below) but I don’t remember a year in which so many species visited at the same time.  This year the only thing we seem to be missing are snowy owls.

Look closely at your feeders.  You might have some exciting visitors.

(photo by Marcy Cunkelman)

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Dec 04 2012

They’re In The Maples!

Published by under Migration,Songbirds

This was it. If I was going to see an evening grosbeak it had to be this winter while they’re irrupting across Pennsylvania.  I missed them at Marcy Cunkelman’s (above), but flocks of 40 to 80 are reported every day at Dave Yeany’s feeders in Marienville.  Last Sunday I made the 2+ hour trip to see them.

Before I left I studied the sound and appearance of these beautiful birds and learned that their call resembles the chirp of a house sparrow (Click here to hear.  If that link doesn’t work, try this one).

When I arrived at 7:30am I heard loud chirps like a house sparrow who’d taken voice lessons.  Close by I saw and heard a real house sparrow.  Aha!  The grosbeaks were here but I couldn’t see them.

I crossed the street to view Yeany’s feeders but there were no grosbeaks there nor in any of the trees.  Another car pulled up.  Surprise!  Fellow birders Tom and Nancy Moeller from Pittsburgh.

Dave Yeany came out to say hello and assured us the grosbeaks would come in at 8:00am.  They would start in the spruce, then settle in the maples, then come to the feeders.  So we waited.

Sure enough at 8:00am the grosbeaks came to the spruce.  Yay! Life birds at last!  But the light was poor.  Rain was coming.  We wanted to see them closer.  We waited.  By 8:30am the grosbeaks landed in the maples but something spooked them and they flew away.  No!

We had come this far and couldn’t bear to leave without seeing the grosbeaks at the feeders.  It began to rain so we retreated to Moellers’ car. It was nice to be waiting with friends.

When the rain subsided at 9:00am we found 40+ evening grosbeaks in the maples preening and nibbling the buds.  They fluttered down level by level.  At last they came to the feeders.  Here, Tom Moeller captured them surrounding a starling.

 

Thanks to Dave Yeany’s hospitality and advice we waited for the grosbeaks to come to the maples.  Our surprise was that the grosbeaks like to eat sugar maple buds.

People like maple products, too.  Dave Yeany has acres of sugar maples that he taps to create pure Pennsylvania maple syrup.  If you visit when he isn’t home you can buy it from the red cupboard on his front porch.

We had the advantage of chatting with Dave and learning about his additional maple products.  I couldn’t resist the maple cream which I’d never tried before.  It looks like honey butter and it tastes great.  Mmmmmmm! Good!

If you visit Dave Yeany’s evening grosbeaks you’ll find a big flock of beautiful birds and a sweet treat at the end.  In the meantime you can “like” Yeany’s Maple Syrup on Facebook.

 

(Male evening grosbeak by Marcy Cunkelman, Nov 2012.  Flock at the tray feeder by Tom Moeller, 2 Dec 2012.  Photo of Yeany’s delicious maple cream by Kate St. John)

3 responses so far

Dec 02 2012

Another Winter Visitor

Published by under Migration

Here’s another bird that visits western Pennsylvania in winter.

I always see snow buntings near Miller’s Pond in Crawford County — the same place as the rough-legged hawk pictured last weekend — but they can be anywhere that resembles their tundra home.

In summer snow buntings are black and white.  In winter they’re cream and brown to match the vegetation.

Cory DeStein found this one two weeks ago while on a Pitt bird club outing to Imperial grasslands in Allegheny County.

(photos by Cory DeStein)

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