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.
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.
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.
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.
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
After a limpkin was discovered yesterday afternoon in a small cove at Moraine State Park (first ever in Butler County!) western PA’s birding world spun on its axis and quickly went to find it. Many saw the bird yesterday including Steve Gosser who shared his photo above.
Limpkins (Aramus guarauna) are very, very rare this far north. Primarily from South America, these mussel and snail-eating wading birds have extended their range only to Florida where they live year round.
So what is a limpkin doing here? And not just “here.” A limpkin showed up at Middle Creek Wildlife Management Area last month and was still there last weekend. Two limpkins were in opposite corners of Ohio.
In fact, limpkins have been doing this crazy Northern Summer Visit thing for a long time but it appears they’ve ramped up since 2016. On 8 July 2023Tim Healy posted a map of Limpkin Firsts in North America at the ABA Rare Bird Alert on Facebook. (The color descriptors are for the map.) “Hot Limpkin Summer forever! Keep it going! Who’s next? Green: home base Blue: historical first records Orange: 2016-2022 first records Red: 2023 first records”
This eBird map shows where they’ve been in 2023 up until 16 August. (I’ve marked the Butler County sighting as a red asterisk.)
Is this an irruption of limpkins similar to the winter irruption of snowy owls? Maybe…
Young night-herons often do an out-of-range dispersal at the end of the breeding season when first-year birds explore to the north, then head home or die during their adventure. Perhaps limpkins are doing it, too. Perhaps they’ve had so much breeding success that there are extra limpkins to try it. (This family of 5 was photographed in Florida in 2014.)
It will take some research to know the answer. The limpkins aren’t saying.
(photos by Steve Gosser and from Wikimedia Commons, maps from Wikimedia and eBird)
Species On The Move uses two decades of eBird data to calculate movement from start to finish within four regions: Upper Midwest & Northeast, Gulf Coast & Southeast, Great Plains, and West. Of course they list First Arrival, Peak, and Last Departure but my favorite markers are:
Noticeability: *** Three asterisks mean we’re really likely to notice this species.
Rapid Migrant Influx: A few may be here already but numbers increase rapidly on this date.
Rapid Departure: Numbers drop quickly on this date though a few will linger.
Have you noticed that orchard orioles, northern rough-winged swallows and willow flycatchers are basically gone? They started leaving in July, then rapidly departed in the first week of August. Yellow warblers and purple martins are not far behind. They’ll leave this week.
The screenshot below is a quick summary of rapid departures as of 13 August 2023. It shows:
Upper Midwest and Northeast region
Pared down to Noticeable birds (*** or **)
Sorted by Rapid Migrant Departure date
Not including some goodies such as Louisiana waterthrush, alder flycatcher and least bittern. (They’re on the website but not “Noticeable” for my pared-down screenshot.)
Noticeable Arrivals: What Rapid Influx will we see this week?
If you haven’t seen them already ruby-throated hummingbirds will make a rapid influx today, 14 August.
The larger region will see increased numbers of common nighthawks and Canada Warblers but in Pittsburgh it’s usually the last week of August.
Here’s a quick summary of Beginning Arrivals as of 13 August 2023 — same parameters as the departures above.
The tables change every day, dropping past dates and picking up new species in the future, so check out BirdCast’s Species on the Move to find out what’s happening near you.
p.s. How will you know if it’s worth going birding? Check BirdCast Migration Tools for forecast maps, live maps and alerts.