Category Archives: Migration

Are the Swifts Gone?

Chimney swift flying in Austin, Texas (photo by Jim McCullough, Creative Commons license, Wikimedia Commons)
Chimney swift, Austin, Texas (photo by Jim McCullough, Creative Commons license, Wikimedia Commons)

16 September 2021

Because chimney swifts (Chaetura pelagica) eat insects on the wing, they eat while they migrate during the day then roost in chimneys at night. In August they begin leaving Pittsburgh and are gone by early October on their way to South America. Mid-September is usually prime time for watching them swirl and drop into chimneys at dusk.

Last year I was thrilled to watch 1,500 of them diving into the roost at the Cathedral Mansions chimney.

Chimney swifts swirl around the Cathedral Mansions chimney at dusk, Sep 2020 (photo by Michelle Kienholz)

But not this year.

Ever since Hurricane Ida passed through Pittsburgh, chimney swifts have been relatively rare and nearly absent from Cathedral Mansions. Earlier this week Steve Tirone, who watches swifts in Squirrel Hill, commented on the low numbers in his area. We’ve seen flocks of about 20 during the day but not the great numbers we usually expect.

Are the swifts gone? Have you seen large flocks of chimney swifts lately? Where?

(photos from Wikimedia Commons and Michelle Kienholz)

Follow The Chickadees

Black-capped chickadees, 2012 (photo by CheepShot via Wikimedia Commons)

9 September 2021

The first three weeks of September are prime time to see warblers passing through Pittsburgh on fall migration. But finding these small, quiet, often greenish birds among the leaves is difficult.

How to find warblers? Listen for and follow the chickadees. Warblers are often with them.

Learn why in this vintage article: Local and Vocal.

(photo from Wikimedia Commons; click on the caption to see the original)

Some Peregrines Don’t Migrate

Peregrine in flight (photo from Wikimedia Commons by Imran Shah)

7 September 2021

As fall migration continues, raptors swell the southbound stream. At the Allegheny Front Hawk Watch (closest to Pittsburgh), broad-winged hawks peak in September, sharp-shinned hawks in October, red-tails in late October, and golden eagles in November. Peregrines are rarely seen, averaging just 34 individuals per season. Their numbers peak in the first week of October.

Peregrines are rare at the Allegheny Front Hawk Watch because they are not numerous to begin with and the watch is far from their typical migration routes. However, many peregrines are never counted on migration because they don’t migrate at all. It depends on where they breed.

Arctic peregrines are truly migratory. Their food sources — nesting shorebirds, seabirds, and songbirds — leave the arctic from July through September so the peregrines must leave, too. A decade ago The Southern Cross Peregrine Project (SCPP) satellite tracked a dozen arctic peregrines wintering in Chile and found that those that breed in northeastern Canada always leave around the September equinox.

From there, unless major weather diverts them, northeastern arctic peregrines typically fly due south to join the Atlantic Flyway. In the spring they track west and follow the Central Flyway. The map below shows five years of satellite tracking of an arctic peregrine, “Island Girl,” on her migration south from Canada to Chile (red) and returning in the spring (blue).

5-year map of arctic peregrine -- Island Girl -- migration routes (map from Southern Cross Peregrine Project)
5-year map of an Arctic Peregrine’s migration routes (Island Girl map from Southern Cross Peregrine Project) NOTE: As of 2021 frg-org is no longer on the Internet

Meanwhile adult peregrines in eastern North America generally don’t migrate at all. Urban peregrines remain on territory year round because their food supply is constant (pigeons) and actually increases in the fall when migratory songbirds arrive for the winter. Adult peregrines may move a short distance during winter scarcity but not necessarily south. Juveniles definitely wander.

The animated PA Game Commission map below shows nine months of wandering by a juvenile peregrine that hatched at the Gulf Tower in Spring 2002. The bird left Pittsburgh on 1 July and wandered to New Jersey, the Chesapeake, Virginia, Maryland and Pennsylvania. This was only the beginning.

Telemetry map of juvenile peregrine falcon banded at the Gulf Tower in Spring 2002 (animation from PA Game Commission, 2003)
Telemetry map of juvenile peregrine falcon banded at the Gulf Tower in Spring 2002 (animation from PA Game Commission, 2003) This animation is no longer available on the PGC website

Juvenile peregrines wander until they reach maturity at age two, then wander to find a breeding territory. Good nesting “cliffs” are scarce so these floaters may wander for years. When they finally claim a nesting site they won’t leave home unless an even better site becomes available.

Peregrine falcon flies by in Trenton, MI, September 2012 (photo from Wikimedia Commons)

Do Pittsburgh’s peregrines migrate? No. I see them in person and on the National Aviary nestcam from November through February when migratory peregrines are in South America.

Pittsburgh’s peregrines stay close to home.

Read more about Canada-to-Chile migratory peregrines in these vintage articles: Going The Distance and Follow an Arctic Peregrine on Migration.

(photos from Wikimedia Commons; click on the captions to see the originals. Telemetry map of juvenile peregrine falcon banded at the Gulf Tower in Spring 2002 (animation from PA Game Commission, 2003). This animation is no longer available on the PGC website)

Intense Migration at The Straits

Black kites in flight (photo from Wikimedia Commons)

20 August 2021

Raptor migration is underway in Europe and will follow soon in North America. One of the best autumn hawk watches is in Spain at the Strait of Gibraltar, the water gap between Europe and Africa.

Northern Africa looks tantalizingly close — only 9 miles away — but the Strait is too dangerous to cross when the wind is from the east. Called the Levant, it blows 25-45 miles per hour toward the Atlantic, strongly suppresses vertical air motion, and can create an inversion within a few thousand feet of the surface. The birds would be forced into the water if they made the attempt.

3D map of the Strait of Gibraltar (image from NASA via Wikimedia Commons)

A week ago the Levant blew for at least three days forcing migrating birds to stop on the Spanish side. Black kites (Milvus migrans) were thick on the ground 13-15 August as they waited it out.

When the weather changed, Monday 16 August was a fantastic migration day.

Meanwhile songbird migration is heating up in North America. BirdCast shows that last night over 100 million birds flew over the eastern U.S. Tonight’s forecast for Pittsburgh (night of 20-21 Aug 2021) promises to be especially intense. Go birding on Saturday!

Update on Sat 21 August, 11am: What a bust! The birds must have flown over without landing. Lots of robins and blue jays. And it was hot out there.

Snapshot of BirdCast map, 20 Aug 2021 at 00:25

Check BirdCast for migration status in your area. Click here for the Pittsburgh forecast. And get outdoors!

(photos from Wikimedia Commons, embedded tweets from Inglorious Bustards, screenshot from BirdCast; click on the captions to see the originals)

Hummingbird Migration Begins This Month

Ruby-throated hummingbird, Missouri (photo by Andy Reago & Chrissy McClarren via Wikimedia Commons)

6 August 2021

Did you notice that hummingbirds were scarce in Pittsburgh from early June to late July? They were here but they were busy nesting and hunting for insects instead of nectar. They reappeared in the last week of July, bolstered by a new population of juveniles.

Right now our hummingbirds are fueling up on nectar before they begin migration in mid August. Meanwhile they are easy to find at feeders and flowers.

This mob of ruby-throated hummingbirds visited a feeder in Atlanta, Georgia on 4 August. …

Here’s a tree full of hummingbirds in the southern California desert on 29 July. Likely species are black-chinned, Anna’s and Costa’s. …

… and here’s a slow motion video in the same southern California backyard.

Follow hummingbird migration on Journey North’s map. Contribute your own sightings here. Weekly tracking begins August 16.

(photo from Wikimedia Commons, tweets by @Scott_Corry1 and @geococcyxcal; click on the captions to see the originals)

Few Migrating Birds But Some Rewards

Gray-cheeked thrush, Frick Park, 21 May 2021 (photo by Charity Kheshgi)

23 May 2021

This year’s weather has made for a lackluster spring migration season in southwestern Pennsylvania. It was suddenly warm in late April then surprisingly cold in the second week of May. During the cold spell migrating birds avoided us by traveling along the Atlantic coast or up the Mississippi valley and Great Plains.

Their absence here was noticeable. Other than one spectacular birding day on 6 May the rest of the month has had a good mix of species but few individual birds. I find it bizarre to spend three hours birding in mid May and see/hear just one American redstart (Setophaga ruticilla) or one Tennessee warbler (Leiothlypis peregrina).

But there have been rewards. Last week in Frick Park Charity Kheshgi found a couple of gray-cheeked thrushes and two mourning warblers on two different days. One gray-cheeked thrush perched in the open.

Gray-cheeked thrush among leaves, 21 May 2021 (photo by Charity Kheshgi)

The mourning warblers remained in the shadows. Scroll right to see his eye shine in the third photo.

And it’s baby season for robins. Cuteness is its own reward.

p.s. Today (and yesterday) there was an olive-sided flycatcher in Frick Park. Click here to se a photo of one that Charity Kheshgi saw at Presque Isle.

(photos by Charity Kheshgi)

Blue And Green

Indigo bunting, Homewood Cemetery, 5 May 2021 (photo by Charity Kheshgi)

8 May 2021

Now that leaves are on the trees the bluest birds have shown up.

Young oak leaves, Schenley Park, 1 May 2021 (photo by Kate St. John)

Charity Kheshgi photographed an indigo bunting (Passerina cyanea) at Homewood Cemetery on Wednesday 5 May …

… and a cerulean warbler (Setophaga cerulea) at Frick Park on 4 May.

Click the white arrows on the right side of photos to see more views.

By the way, today is Migratory Bird Day. Don’t miss this opportunity to get outdoors.

(photos by Charity Kheshgi via Instagram)

How Do They Get Here?

Canada Warbler at Schenley Park, 25 May 2019 (photo by Kuldeep Singh)

5 May 2021

Early May is exciting for Pittsburgh birders as beautiful migratory songbirds arrive in our area. Some come from as far away as South America and are en route to northern Canada. Some stay to nest, others move on. What map are they using? How do they get here?

Much of migration remains a mystery. This list is just a summary of the high points. If you have more to add, please leave a comment!

Basic Onboard Navigation System:

Migratory birds are born with a basic navigation system that improves with experience. First-of-year birds fly south in the fall with these instructions: Fly in [this] direction for [this] long.

Those born with a faulty compass head the wrong way and end up on Rare Bird Alerts.

My Life Bird lark sparrow was found at Seal Harbor, Maine. Though usually a western bird, he flew east instead of south.

Experience:

After a bird has made the trip just once, it remembers the route and retraces it year after year. The lark sparrow in Seal Harbor showed up every September for the typical life span of a lark sparrow. His compass error didn’t hurt him.

Birds can be thrown off course by bad weather but they have additional navigational aids.

“Seeing” Earth’s Magnetic Field:

European robin (photo from Wikimedia Commons)

There’s evidence that birds can “see” Earth’s magnetic field to help them navigate, though we’re not sure how. A 2018 study of European robins and zebra finches reported that a cryptochrome protein in their eyes (Cry4) helps them see the blue light associated with magnetism. Cry4 increases during migration season and ebbs thereafter. Intriguing!

Orienting by polarized light at sunrise and sunset:

Savannah sparrow in Juneau, Alaska (photo from Wikimedia Commons)

Before 2006 scientists knew that birds orient themselves at sunset. Then they learned how.

Researchers from Virginia Tech in Blacksburg and Lund University in Sweden say experiments with savannah sparrows in Alaska show the birds take readings of polarized sunlight at sunrise and sunset and use them to periodically recalibrate their magnetic compasses.

The Baltimore Sun: Sunlight is key for Bird migration

Navigating by smell:

Gray catbird (photo from Wikimedia Commons)

Birds even use their sense of smell! A study of gray catbirds in 2009 showed that those who’d made the trip before used smell to course-correct.

How do they get here? It’s even more amazing than we thought!

To learn more, click the embedded links above.

(photos by Kuldeep Singh, Suunto, and Wikimedia Commons; click on the captions to see the originals)

Frick Park on the Cusp of May

  • Barred owl, Frick Park, 2 May 2021 (photo by Charity Kheshgi)

2 May 2021

Frick Park and adjacent Duck Hollow are two of the hottest birding hotspots in southwestern Pennsylvania. So many birds show up during spring migration that we birders spend hours there in April and May.

Frick’s 644 forested acres are a green oasis halfway through Pittsburgh’s developed metro area. The Monongahela River at Duck Hollow beacons to water and shorebirds while the woods attract songbirds to refuel before continuing north.

screenshot of Pittsburgh, PA regional map, google.com

The Pittsburgh Parks Conservancy map of Frick Park shows how Duck Hollow (furthest point south) connects to the larger park. The birding is so good in that corridor that I often walk from Duck to Frick. If the two locations were a single hotspot their combined species count would probably surpass 200. Click here to download the Frick Park map.

screenshot of Frick Park map from Pittsburgh Parks Conservancy. Click here to download the map

Charity Kheshgi photographs birds at Frick Park and/or Duck Hollow nearly every day. Her slideshow above includes a few of the birds she saw on the cusp of May. See more by following her on Instagram at https://www.instagram.com/charitykheshgi/

p.s. I was there for the Blackburnian warbler but missed the barred owl because I didn’t visit Frick on 2 May. So many birds, so little time!

(photos by Charity Kheshgi, maps from Google and Pittsburgh Parks Conservancy)

Chimney Swifts Are Back In Town

Chimney swifts illustration from Crossley ID Guide to Eastern Birds via Wikimedia Commons

29 April 2021

Yesterday a small flock of chimney swifts (Chaetura pelagica) returned to my city neighborhood and swirled to roost in the Cathedral Mansions chimney.

Though there were only 11 birds, these “cigars with wings” were the leading edge of the huge flocks heading north. Those who nest in Pittsburgh will pair up quickly and start building nests in early May.

How do chimney swifts court and build nests? Check out these Fun Facts About Cigars With Wings.

Chimney swift in hand at banding (photo from Wikimedia Commons)