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?
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.
Today is #WorldMigratoryBirdDay. A good time to celebrate the incredible migration of the Beijing Swift (????). From late Jul until their return in Apr, these birds – that can fit into the palm of your hand – fly c26,000km and cross 20 borders.https://t.co/2xSe8FHlmepic.twitter.com/oL5EBy90ff
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.
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.
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).
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.
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)
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.
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.
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.
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.
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.
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 birdsafepgh.org 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.
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.
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)
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.
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 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) 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.
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.
(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)
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.
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.
#KiteSurfing! Masses of Black Kites swarm and surf the strong easterly crosswind today ! The magic of The Straits!
The easterly wind continues today and the departure gate is still shut for the majority of the soaring migrants. Not thousands, but tens of thousands gather! pic.twitter.com/xLUmHwpebF
When the weather changed, Monday 16 August was a fantastic migration day.
??? #migration here in The #Straits today with @ornid – 18,425 Black Kite, 4,556 White Storks, Booted and Short-toed Eagles, Eleanora’s Falcon, a diff juv Lanner Falcon, Montagu’s and Marsh Harriers, Black-winged Kite and European Honey Buzzards and European Bee-eaters! pic.twitter.com/BqIMqwwwEt
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. …
