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.
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)
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).
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.
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)
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. …
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.
The mourning warblers remained in the shadows. Scroll right to see his eye shine in the third photo.
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.
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.
Orienting by polarized light at sunrise and sunset:
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.
Barred owl, Frick Park, 2 May 2021 (photo by Charity Kheshgi)
Baltimore oriole, Frick Park, 1 May 2021 (photo by Charity Kheshgi)
Chipping sparrow, Frick Park, 2 May 2021 (photo by Charity Kheshgi)
Great-crested flycatcher, Frick Park, 28 April 2021 (photo by Charity Kheshgi)
Northern flicker, Frick Park, 23 April 2021 (photo by Charity Kheshgi)
Blackburnian warbler, Frick Park, 28 April 2021 (photo by Charity Kheshgi)
Purple finch, Frick Park, 2 May 2021 (photo by Charity Kheshgi)
Yellow-rumped warbler, Frick Park, 2 May 2021 (photo by Charity Kheshgi)
Rose-breasted grosbeak, Frick Park, 2 May 2021 (photo by Charity Kheshgi)
Red-winged blackbird, Frick Park, 23 April 2021 (photo by Charity Kheshgi)
Mallard and spotted sandpiper, Duck Hollow, 30 April 2021 (photo by Charity Kheshgi)
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.
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.
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!
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.