The blackpoll’s transoceanic path was proven in a 2015 study by Bill DeLuca and the Vermont Center for Ecostudies. VCE writes:
Bill DeLuca (Northeast Climate Science Center) and VCE solved this great modern-day avian mystery. Using light-level geolocators attached to Blackpoll Warblers in Vermont and Nova Scotia, DeLuca and colleagues documented the longest distance non-stop overwater flights ever recorded for a migratory songbird. During October, Blackpoll Warblers initiate a ~3-day non-stop transoceanic flight of ~2500 km from the north Atlantic Coast to Hispaniola and Puerto Rico. Radar data show migrating songbirds fly at 2,600 to 20,000 feet while making this journey. After a few weeks, they fly onto Columbia or Venezuela where they overwinter. Their spring migration route takes them over Cuba to Florida, where they journey up the eastern US seaboard to reach their breeding grounds in late May.
Notice in this eBird abundance map for the week of 2 Nov that blackpolls are:
bunched up on the East Coast from Massachusetts to North Carolina
at a stopover on Puerto Rico and
early migrants have already arrived in South America.
Watch them throughout the year in this eBird abundance animation.
Of course I wondered if blackpoll warblers sleep in flight during their 3 day transoceanic trip, but we won’t find out any time soon. Blackpolls are way too small to wear the sleep monitoring gear used on the great frigatebird.
(photo from Wikimedia Commons, maps from eBird Weekly Abundance; click on the captions to see the originals)
Joe, Sam and Jared joined me yesterday morning on an adventure to see Bird Lab at Hays Woods. The weather was perfect as we walked more than half a mile to the banding station. There we found Nick Liadis and his assistants about to do the second net-check of the day.
The mist nets that capture songbirds are set up in “alleys” of vegetation where birds might fly across. If a bird doesn’t see the net and tries to fly through, it falls into the pocket of extra netting material where it waits to be retrieved. Banders check the nets every half hour.
Captured birds are brought back to the banding table in cloth bags to keep them calm. Our group watched as Nick prepared to band three birds from the recent net check.
Each bag contains a surprise. The first was a recaptured Cape May warbler (Setophaga tigrina), originally banded on 20 Sep when it weighed 10.9g. Yesterday it weighed 13.8g for a gain equivalent to the weight of a ruby-throated hummingbird. Such a small bird in Nick’s hand, below.
It was the second Cape May warbler recapture this fall. The first one increased its weight by 50% in two weeks. About the first one, Nick wrote:
A cool recapture from my Hays Woods banding station! This Cape May Warbler was banded on 9/13 and we captured her again two weeks later. She originally weighed 11.6g and today weighs 15.4g. Interesting to see how long some of these birds hang around. I’d imagine she’ll be on her way very soon.
— Nick Liadis message, 27 Sep 2023
Next on the agenda was a hatch year (meaning “hatched this year”) male black-throated blue warbler (Setophaga caerulescens). His color was blue, but not vibrantly so, and his throat had tiny white flecks on it. I had seen a dull bird like this in Frick Park last week and didn’t realize that meant he was young.
At each successive net check new species showed up.
The hatch year hermit thrush (Catharus guttatus) shown at top was a sign that the mix of migrant species is changing. The insect eaters are nearly gone while the fruit and nuts migrants have arrived (*see note).
The hatch year female house finch, below, was probably born at Hays Woods. Many house finches in the eastern U.S. are permanent residents. Perhaps she will be, too.
By 10:00am we’d been there an hour, it was getting hot (the high yesterday was 85°F!) and the birds were less active. Three of us hiked to the overlook and returned for one more net-check. This time only one bird was captured, a hatch year house wren (Troglodytes aedon) that Nick had banded on 9 August. This bird has spent the last two months foraging at Hays Woods and soon it will migrate to Central or South America.
Thanks to Jared Miller for sharing his photos, shown above.
Bonus Bird: After the banding, a rare bird at Duck Hollow:
At 10:30am I received an alert that a migrating American avocet (Recurvirostra americana) was hanging out at Duck Hollow. Avocets in Allegheny County are One Day Wonders. I had never seen one here because I waited a day to go see them. So I made the short trip from Hays Woods to Duck Hollow and digiscoped this lousy picture. The light was too bright to see its faint orange color but you get the idea.
p.s. (*) Two of the phases of fall migration: ** Insect eaters such as warblers, flycatchers, swifts and swallows migrate through in September because the bug population is going to die when cold weather hits. ** Fruit and nut eaters, including thrushes and sparrows, pass through in October.
Right now warbler migration is at its autumn peak in southwestern Pennsylvania but, as usual, the birds are hard to identify. Their fall plumage is dull and confusing, they move fast so we never get a good look at them, and we don’t get much practice because many of them are here only in September. And then they’re gone.
This year it dawned on me that the magnolia warbler (Setophaga magnolia) is super-easy to identify if all you see is its butt, as shown at top and below.
Note that the magnolia warbler is the only warbler with a white belly, white undertail coverts, white undertail and a large black straight-edged tip on the tail. It looks as if this warbler was dipped tail first in black paint.
On some juveniles the tip is dark gray but the pattern is the same.
So this view is the best way to identify a magnolia warbler.
I highly recommend the 560-page The Warbler Guide by Tom Stephenson and Scott Whittle which I use at home after noting the warbler’s key features in the field. In my opinion the book is indispensable if you take photographs.
For nearly 30 years ultralights have been used to establish safe migration routes for endangered geese and cranes as they are reintroduced to the wild.
In 1993 ultralight pioneer Bill Lishman, along with Joe Duff, conducted the first ever human-led bird migration by guiding a small flock of young Canada geese from Ontario to Virginia. His experiment proved that young geese imprinted on an ultralight will follow the aircraft and learn the migration route. After leading the birds just once, in one direction, the geese knew the route and returned on their own in the spring.
Christian “Birdman” Moullec was the first to do it in Europe when he guided lesser white-fronted geese (Anser erythropus) from their future breeding grounds in Sweden to new wintering grounds in Germany in 1999. He has since led red-breasted geese (Branta ruficollis) and many other species.
Nowadays, to raise money for his conservation efforts, Christian Moullec offers tourists ultralight flights with the birds.
Pittsburgh’s bird migration forecast looks great for three days in a row. Last night through Friday night will see a huge passage of birds overhead with excellent birding opportunities today, Friday and Saturday.
Here’s what migration radar looked like at 5:00am this morning.
Lots of species left recently but most of them were shorebirds. Since Pittsburgh doesn’t have a shore we rarely see those listed below. Occasionally a lesser or greater yellowlegs is reported but don’t expect to find one now.
Here’s a quick summary of rapid departures as of 14 September 2023 in a screenshot from BirdCast. Note that cedar waxwings are here right now but will rapidly depart around 27 September. Yellow-billed cuckoos on the list because I always hope.
Peak Influx: What will we see this week? Warblers!
For the Upper Midwest and Northeast region, 13 to 17 September is the peak of warbler migration.
I’ve featured the ovenbird because yesterday (last night!) was its peak influx point. No surprise then that Nick Liadis banded one yesterday at Hays Woods during Linda Roth’s 40 Acres a.k.a. Hays Woods Enthusiasts live stream. Check it out here.
And if you thought you’d seen a lot of magnolia warblers already, the next few days will be exceptional. They reach their regional peak influx on Sunday.
Here’s a screenshot of the Noticeable Peak Influx as of 14 September 2023. Note the exclamation point next to magnolia warbler in the chart below!
With so many birds on the move, now’s the time to get outdoors. Be sure to check BirdCast for the latest forecast.
Common green darner, Virginia (photo from Wikimedia)
Variegated meadowhawk, California (photo from Wikimedia)
Black saddlebags, California (photo from Wikimedia)
Global skimmer, Laos (photo from Wikimedia)
Spot-winged glider, Texas (photo from Wikimedia)
10 September 2023
On the evening of Friday 8 September, Marianne Atkinson noticed hundreds of dragonflies patrolling a field near her house in Dubois, PA. Other folks as much as 20 miles away were commenting on the same thing and posting videos online. What were these bugs up to? Marianne sent me her video …
… and this Facebook post from the McKean County Conservation District explaining the phenomenon. Dragonflies are migrating.
The green darner is the most common migratory dragonfly in Pennsylvania but is only one of 16 migratory species in North America. The five main migrants are pictured in the slideshow at top and listed below from Donna L Long’s website.
Green darners have a multi-generational migration. The individuals we see flying south right now will not return but will be the grandparents of those who journey north next spring.
Recent research has indicated that the annual life cycle of green darner (Anax junius) is likely composed of at least three different generations. The first generation emerges in the southern end of its range in early spring and migrates northwards through spring and summer. The second generation emerges in the northern end of its range in summer and migrates southwards in fall. The third generation occurs in the south during the winter and does not migrate.
When dragonflies migrate during the day in Pennsylvania they follow the same flight paths and fly on the same prime migration days as the hawks. I often see dragonflies at hawk watches where I’m glad they’re eating mosquitos and flying ants on the wing.
Green darners seem to go far but for real long distance the global skimmer wins the prize, migrating from India to Africa across the Indian Ocean! It also occurs in North America.
The migration spectacle at the Strait of Gibraltar is still underway as thousands of birds stretch their wings and fly to Africa. They can see their goal from the European side but sometimes the wind is a brutal wall that prevents their crossing. On 4 September the wind was right and they didn’t have to flap. Thousands glided south to Morocco.
569 White Stork cruised out to Africa just above us! 570 European Honey Buzzards, as 222 Booted Eagles, increasing numbers of Short-toed Eagles & 274 European Bee-eaters dodged migrating Pallid & Common Swifts! pic.twitter.com/OxrulL3BZ2
The storks making the crossing had nested in Western Europe and are heading for Sub-Saharan Africa for the winter.
Fifty years ago white storks were extinct in most of Western Europe and this spectacle at the Straits died with the absent birds. Reintroduction programs in the late 20th century brought them back to a growing population of now 224,000 to 247,000 European white storks.
For those who lived through the lean years, their tears at the Straits are tears of joy.
(credits are in the captions including links to the sources)
Migration is exhausting work and since warblers migrate at night, they must rest and refuel during the day. Food and good cover are both essential at their rest stops. Sleeping is a dangerous activity where predators lurk.
A study published in Current Biology, August 2019, revealed one way that migrating warblers manage these dangers and demands: They adjust their sleep postures depending on their physical condition and physiological needs. Plump, well-muscled birds tend to sleep with their heads held upright, while scrawnier warblers tuck their heads into their feathers, a posture that makes them more vulnerable to predation but helps them conserve their much needed energy.
Fit warblers can afford to be vigilant. They puff up and sleep in a watchful posture, sometimes out in the open. This makes them ready to escape at a moment’s notice.
Some long distance migrants, such as the ocean-going great frigatebird, can sleep in flight.
A 2016 study equipped great frigatebirds (Fregata minor) with EEG equipment and proved that they sleep while flying though they get less sleep in the air than on land. Read more in this vintage article.
It would be nice to safely sleep while doing other things. Yawn! I’m ready right now.
(photos from Wikimedia Commons, see links in the captions)
Olive-sided flycatchers (Contopus cooperi) are rare birds in Pittsburgh. Not only have they declined 78% since 1970, but they are only present on migration and then just one or two per season. When three individuals were found on the same day, Friday 25 August, in Allegheny County it was rare indeed. These three were not the same bird:
Sewickley Heights Borough Park at 8:20am, seen recently on Monday 28 Aug
Hartwood Acres, Saxonburg Fields at 10:50am
Homewood Cemetery at noon
Though olive-sided flycatchers nest from Alaska to Newfoundland and southward into the Cascades and Rockies, not much is known of their migration routes. In the fall the eastern birds generally flow westward within Canada, then hang a left at Minnesota and migrate through the Great Plains and eastern Rockies. You can see their relative abundance from the 3rd week of August through the 3rd week of October in this slide show.
Alaska’s breeding olive-sided flycatchers are declining rapidly and have one of the longest migrations of any flycatcher — from Alaska to Peru. Migratory stopover sites are very important for their survival but nobody knew where they went so a study team, headed by Julie C. Hagelin, decided to track the birds’ migration by catching them in mist nets and attaching geolocator backpacks.
What they discovered when the birds returned is that Alaskan breeders fan out across the Rockies on their way south, some as far east as Texas, before they head through Mexico to South America. They also found 13 important stopover sites that are critical to the birds’ survival on migration. Their favorite spots are slightly different in Central America in fall versus spring. Two of the 13 sites are in the U.S. Cascade Mountains. All the sites are on these maps.
Pittsburgh never figures heavily in the olive-sided flycatcher’s travel agenda though this year we seemed to be an attractive stopover. Our birds probably come from breeding sites in eastern Canada.
Are our olive-sided flycatchers stopping at the same places in Central America as the Alaskan group? We won’t know until some runs a similar study in eastern Canada.
(photo from Wikimedia Commons, abundance maps from eBird, stopover maps from DeGruyter; origin links are in the captions)
Fall migration is underway across the Northern Hemisphere. Some birds migrate alone or in small flocks that don’t attract much attention. Others gather in such massive flocks that they are hard to miss.
At pinch points along their migration routes from Europe to Africa, white storks (Ciconia ciconia) travel in very large flocks like the kettles of broad-winged hawks in North America. Two such pinch points are in the airspace over Israel, above, and at the Strait of Gibraltar.
In this short video white storks are about to cross the Straits from Spain to Morocco but hit a wall in the air — the levant wind blowing from the east — so they wheel back. They did not leave Spain that day.
In North America semipalmated sandpipers (Calidris pusilla) migrate in massive numbers from their breeding grounds in the Arctic to the shores of South America.
One highlight on our @EagleEyeTours trip to New Brunswick is a visit to Johnson Mills Shorebird Reserve. Besides the incredible Bay of Fundy tides, we witnessed the spectacle of 65+ THOUSAND Semipalmated Sandpipers roosting, flocking and doing synchronized aerial acrobatics. pic.twitter.com/6aqAJUtt9p