Category Archives: Migration

Long Distance Migrant to …

Common swifts in flight (illustration by Jos Zwarts via Wikimedia Commons)

12 October 2021

North American birds that eat flying insects migrate to Central and South America for the winter. Where do Asian insectivores go? Until 2015 the winter home of the common swifts that nest in Beijing was a mystery.

Common swifts (Apus apus) breed across Europe and Asia from Ireland to North China. Those from Europe are known to winter in Africa but where do the far eastern swifts go?

Breeding range of the common swift (altered from range map on Wikimedia Commons)

In the spring of 2014 the Beijing Swift Project tagged 31 common swifts with geolocators at the Summer Palace. The birds nested in China, then left in July. When they returned nine months later in April 2015 thirteen were recaptured. Their geolocator data revealed that the swifts had traveled east to the Caspian Sea then south to South Africa, a round trip of 16,000 miles (26,000 km). During those nine months the birds never landed! Their destination is yellow on the map below.

Range map of the common swift from Wikimedia Commons

This tweet from October 2020 shows their journey.

Since Africa is this species’ winter home, those that breed in North China must travel farthest to get there. The journey is so long for Beijing’s swifts that they spend more time in Africa (4 months) than they do in Beijing (3 months).

Read more about the common swifts of China and see their migration maps at the Beijing Swift Project.

Common swift in flight; this one is from Barcelona (photo from Wikimedia Commons)

(photos, maps and illustrations from Wikimedia Commons)

Birding in the Rain

Brown thrasher in a puddle (photo from Wikimedia Commons)

1 October 2021

Pittsburgh has been warm and sunny for a week now and will continue to be pleasant through tomorrow. Then we’ll have to go birding in the rain.

@GetToKnowNature found unexpected beauty in the rain at Sandy Hook, part of the Gateway National Recreation Area in New Jersey that includes the historic Fort Hancock.

Map of Gateway National Recreation Area highlighting Sandy Hook (map from Wikimedia Commons)

The narrow peninsula is a natural stopoff for migrating land birds in inclement weather.

Can you identify the bird songs in the video? The photos provide a hint.

Brown thrasher in the shadows (photo from Wikimedia Commons)

(photos and map from Wikimedia Commons; click on the captions to see the originals)

How Fast Do Songbirds Migrate?

Flock of robins, early morning (photo by Carl Berger Sr on Flickr via Creative Commons license)

27 September 2021

During fall migration warblers pass through Pittsburgh, followed by thrushes, then sparrows. We see them during the day after they’ve flown all night. Where were they yesterday? How far will they fly tonight? How fast are they traveling? What is their destination?

The answers are weather dependent, of course, but they also vary by species. Here are three recent songbird examples.

Wood thrush (Hylocichla mustelina)

Wood thrush in September (photo by Andy Reago & Chrissy McClarren from Wikimedia Commons)

Wood thrushes (Hylocichla mustelina) breed across the eastern U.S. and southeastern Canada, then spend the winter in Central America.

Wood thrush range (map from Wikimedia Commons)

In 2009 a geolocator study of wood thrushes by Bridget Stutchbury found that:

  • Wood thrushes fly more than 311 miles a day on migration. If they fly 8-10 hours per night their air speed is 30-38 miles per hour.
  • They dawdle in the fall by stopping over in the southern U.S. or the Yucatan for one to four weeks before proceeding to their final destination.
  • Wood thrushes return two to six times faster in spring because they barely stop at all.
  • They shorten the trip by flying across the Gulf of Mexico overnight, a distance of 600 miles from the Yucatan to Louisiana.

Where was that wood thrush yesterday? Maybe north of Toronto, Ontario. When he leaves how far will he fly? Perhaps to Lexington, Kentucky.

Blackpoll warbler (Setophaga striata)

Blackpoll warbler in autumn (photo from Wikimedia Commons)

Blackpoll warblers (Setophaga striata) spend a lot of time fattening up before they leave North America for their wintering grounds in Brazil because they fly non-stop over the Atlantic Ocean to get there.

Their route averages 1,900 mi (3,000 km) over open water, requiring a potentially nonstop flight of around 72 to 88 hours. They travel at a speed of about 27 mph (43 km/h).

Wikipedia Blackpoll Warbler account
Blackpoll warbler breeding and wintering range (map from Wikimedia Commons)

Some blackpolls take off from Cape Cod. Some launch from coastal Virginia. Where was that blackpoll yesterday? If you’re asking this in Pittsburgh he might not have been very far north. Where will he be tomorrow? If you’re asking this on the U.S. coast the answer is “over the Atlantic Ocean.”

American robin (Turdus migratorius)

American robin (photo from Wikimedia Commons)

American robins (Turdus migratorius) take their time in the fall. Since they can live year round in much of the U.S. those that leave their breeding grounds (yellow on map) can afford to linger on their way south. Robins leave when the ground freezes or is covered by snow. Some travel as far as Florida, Mexico and Central America but most do not.

American robin range (map from Wikimedia Commons)

When on the move American robins have been clocked at 20-36 mph. They are faster when migrating than when they fly in our backyards.

So where was that robin yesterday? Probably here in Pittsburgh. Where will he be tomorrow? If he decides to fly all night he can reach Lexington, Kentucky with the wood thrush.

(photos and maps from Carl Berger on Flickr and Wikimedia Commons; click on the captions to see the originals)

Waves of Monarch Butterflies

Monarch butterfly on salvia (photo from Wikimedia Commons)

26 September 2021

In mid-to-late September monarch butterflies (Danaus plexippus) pass through western Pennsylvania on the way to their winter home in the Sierra Madre Mountains of Michoacán, Mexico. Last week I saw quite a few flying southwest, one at a time.

Each butterfly travels alone, migrating 50-100 miles a day and resting at night. By the time the eastern population has reached Texas their paths converge.

Monarch butterfly fall migration patterns (map from US Forest Service)

They look for good roosting habitat and end up together, often in pine trees, to wait out the night or bad weather.

Migrating monarch butterflies resting on a pine tree on Fire Island, NY (photo from Wikimedia Commons)

When flight conditions suddenly improve they are spurred to leave. They all depart at once. That’s what happened on 21 September 2021 in west-central Texas after a cold front passed through.

Watch waves of monarchs light up the radar in this Facebook post at Garden Naturally Group.

(photos from Wikimedia Commons, map from US Forest Service; click on the captions to see the originals)

Pittsburgh Lights Out For Birds

Pittsburgh at night in 2016 (photo from Wikimedia Commons)

22 September 2021

Each year up to 1 billion birds die by hitting windows in the U.S. The problem is especially acute during spring and fall migration when thousands of birds pass through North American cities in the dark and are fatally attracted to city lights. This month a coalition of Pittsburgh’s business and conservation organizations joined Audubon’s Lights Out program to protect birds migrating through our area.

Pittsburgh looks beautiful with all the lights on but that beauty is dangerous to migrating birds. Songbirds use celestial light to navigate and are lured by artificial lights, become confused and circle them. Some immediately crash into buildings. Others land in the city and try to leave after dawn but they mistake the reflections of trees and sky for the real thing and fly headfirst into glass and windows. Some are stunned. Half to 3/4 of them die. Warblers and thrushes are especially vulnerable.

Window-killed migratory thrush, Portland, OR, October 2013 (photo from Wikimedia Commons)

This month six Pittsburgh organizations formed a partnership to save the birds: Building Owners and Managers Association of Pittsburgh (BOMA), BNY Mellon, BirdSafe Pittsburgh, Carnegie Museum of Natural History, Pittsburgh Downtown Partnership, and the National Aviary.

partner logos

The National Aviary explains how it works:

Lights Out is a voluntary program that encourages building owners and tenants to turn off as much internal and external building lighting as possible at night, particularly lights on upper floors and lobbies.

The first Lights Out Pittsburgh launched 1 September 2021 with participating buildings BNY Mellon, Carnegie Science Center, Eleven Stanwix, House Building, Law & Finance Building, Point Park University, Union Trust Building, United Steelworkers’ Building, 100 Ross, 20 Stanwix, 600 Waterfront and others turning off unnecessary lighting from midnight to 6 a.m. The initiative runs through November 15. Businesses and households can take the pledge to turn their lights out at any point during the migration season.  

National Aviary: Pittsburgh Joins Lights Out Program to Protect Migratory Birds

BirdSafe Pittsburgh is currently gathering volunteers to document bird fatalities and rescue injured birds. The resulting data will track the progress made by the Lights Out initiative. You can help by visiting to sign up.

How well is Pittsburgh doing just three weeks into the program? We have a long way to go but we are already on our way. This webcam snapshot from Discover The Burgh on this rainy 22 September shows that the BNY Mellon building is dark but not UPMC, Gulf, Koppers, Highmark, PPG and many many more.

Screenshot of Pittsburgh skyline from webcam, 22 Sep 2021, 5:10am

Learn more about Pittsburgh’s Lights Out Initiative at the National Aviary’s press release and at BirdSafe Pittsburgh’s Lights Out webpage.

Check out Pittsburgh’s skyline at any time of day and learn about Pittsburgh’s attractions and favorite spots at Discover the Burgh.

p.s. If you have any contacts at Downtown buildings, tell them about the Lights Out program.

(photos from Wikimedia Commons, logos from BirdSafePgh Lights Out Pittsburgh, screenshot from Discover the Burgh; click on the captions to see the originals)

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?

p.s. Pittsburgh is not alone. This 15 Oct 2021 article in the Washington Post remarks on the absence of migrating swifts in Baltimore + see Kathleen’s comment below about the lack of swifts in Asheville, NC. Uh oh!

(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)