Category Archives: Migration

Undertail Tells The Tale

Magnolia warbler in fall, Sept 2018 (photo by Dave Brooke)

19 September 2023

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.

Magnolia warbler shows its undertail, May 2019 (photo from Wikimedia Commons)

The “maggie” has a unique pattern on its undertail, easy to see on the free Visual Finders PDF, downloaded from The Warbler Guide. I’ve highlighted the magnolia warbler on this screenshot of Page 15.

Visual Finders Download, Eastern Undertails page from The Warbler Guide I have highlighted the Magnolia tail

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.

Magnolia warbler excerpt from Visual Finders Download, Eastern Undertails page from The Warbler Guide

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.

Underside of a Spring plumage magnolia warbler (photo from Wikimedia Commons)

The undertail tells the tale!

Download Stephenson & Whittle’s free Visual Finders PDF at The Warbler Guide.

(photos by Dave Brooke, diagrams from The Warbler Guide free download)

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.

Flying With The Birds

Ultralight leads whooping cranes on migration (photo from Wikimedia Commons)

15 September 2023

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.

Red-breasted goose and lesser white-fronted goose (photos from Wikimedia Commons)

Nowadays, to raise money for his conservation efforts, Christian Moullec offers tourists ultralight flights with the birds.

Learn what it’s like to take one of his flights in: A Man, a Tiny Aircraft, and a Flock of Geese: Flying Among Birds in France. See the magic in this video from National Geographic.

video embedded from National Geographic on YouTube

Visit Moullec’s website at Fly With Birds.

(credits are in the captions)

Migration! Arrivals & Departures, 14 Sep

Ovenbird, Oct 2020 (photo by Steve Gosser)

14 September 2023

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.

Birdcast Live Migration screenshot for 14 Sep 2023, 5:00am

During this massive movement some species are departing, some arriving. Let’s take a look again at Birdcast’s regional list of Species On The Move, described in detail last month, to learn what we can expect to see.

Noticable Departures: Who Just Left?

Greater and lesser yellowlegs, April 2020 (photo by Lauri Shaffer)

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.

pared-down screenshot of BirdCast Species On The Move, noticeable Last Departures, Upper Midwest & Northeast

Peak Influx: What will we see this week? Warblers!

Nick Liadis checking the age of an ovenbird, Sept 2022 (photo by Kate St. John)

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.

Magnolia warbler in autumn (photo by Steve Gosser)

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!

pared-down screenshot of BirdCast Species On The Move, migration Peak by species, Upper Midwest & Northeast

With so many birds on the move, now’s the time to get outdoors. Be sure to check BirdCast for the latest forecast.

(photos from Steve Gosser, Lauri Shaffer, Kate St. John. Tables are modified screenshots from BirdCast’s Species On The Move for the Upper Midwest and Northeast. Be sure to check BirdCast for the latest data)

Dragonflies Are Migrating

  • Common green darner, Virginia (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 …

video by Marianne Atkinson

… 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. 

Wikipedia: Green Darner

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.

(video from RoundGlass Sustain on YouTube)

p.s. There are 7,000 species of dragonflies on Earth. Only 25-50 species migrate, making this a very unusual feat.

(photos from Wikimedia Commons, video by Marianne Atkinson and an embed from Youtube)

Thousands Glide To Africa

White stork in flight (photo from Wikimedia Commons)

6 September 2023

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.

Among the flocks were hundreds of white storks (Ciconia ciconia), seen in this tweet from Inglorious Bustards.

The storks making the crossing had nested in Western Europe and are heading for Sub-Saharan Africa for the winter.

Range map and flyways of the white stork (map from Wikimedia Commons)

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)

Sleeping On Migration

Sparrow asleep in New Mexico (photo by Larry Lamsa via Flickr Creative Commons license)

31 August 2023

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.

New York Times: Some Migratory Birds Sleep Better Than Others, August 2019

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.

Sardinian warbler asleep on a branch (photo from Wikimedia Commons)

Exhausted warblers hide in thickets and tuck their heads under their wings. This provides much needed rest and protects against heat loss but makes them vulnerable to predators. Interestingly, these same birds sleep less than those in good condition because they have to spend more time foraging.

Bird sleeping with head tucked under wing (photo from Wikimedia Commons)

Some long distance migrants, such as the ocean-going great frigatebird, can sleep in flight.

Great frigatebird in flight (photo from Wikimedia Commons)

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 Stop to Refuel

29 August 2023

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.

Olive-sided flycatcher weekly relative abundance from eBird Status and Trends

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.

(illustration from DeGruyter: Revealing migratory path, important stopovers
and non-breeding areas of a boreal songbird in
steep decline

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)

Massive Migration

White stork flock migrating over Israel, Sept 2007 (photo from Wikimedia Commons)

19 August 2023

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.

Semi-palmated sandpipers on migration in Maine (photo from Wikimedia Commons)

At the Bay of Fundy the flocks can number in the hundreds of thousands in August and early September.

(photos from Wikimedia Commons; tweets embedded)

A Limpkin Irruption?

Limpkin at Moraine State Park, 16 July 2023 (photo by Steve Gosser)

17 August 2023

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 2023 Tim 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”

ABA Rare Bird Alert on Facebook: 8 July 2023, Tim Healy

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.)

eBird map of limpkin sightings in 2023 up until 16 August 2023

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.)

Adult limpkin with 4 young, Winter Haven, Florida, 2014 (photo from Wikimedia Commons)

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)

Migration! Arrivals & Departures This Week

Ruby-throated hummingbird, Annandale, NJ, 5 Sept 2012 (photo by Ellen & Tony via Flickr Creative Commons license)

14 August 2023

A lot of us think that fall migration doesn’t start until the end of August, but guess what? BirdCast resumed migration predictions on 1 August and their regional lists of Species On The Move show an influx of 10 noticeable species this week while five have already left, or are about to. Don’t wait to go birding. Check BirdCast tools to find out why.

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.

The tables are grouped by region with Pittsburgh in the heart of BirdCast’s Upper Midwest & Northeast region. These dates are estimates but they’re good ones. Let’s take a look at who left and who’s coming soon.

Noticable Departures: Who Just Left?

Orchard oriole singing at Frick Park, 26 April 2023 (photo by Charity Kheshgi)

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.)
pared-down screenshot of BirdCast Species On The Move, noticeable Last Departures, Upper Midwest & Northeast

Noticeable Arrivals: What Rapid Influx will we see this week?

Immature ruby-throated hummingbird (photo from Wikimedia Commons)

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.

Common nighthawk photo by Chuck Tague; Canada warbler photo by Kuldeep Singh

Here’s a quick summary of Beginning Arrivals as of 13 August 2023 — same parameters as the departures above.

pared-down screenshot of BirdCast Species On The Move, noticeable Beginning Arrivals, Upper Midwest & Northeast

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.

(photos from Wikimedia Commons, Charity Kheshgi, Chuck Tague, Kuldeep Singh. Tables are modified screenshots from BirdCast’s Species On The Move for the Upper Midwest and Northeast. Be sure to check BirdCast for the latest data)