A long term study of white storks (Ciconia ciconia) in Germany and Austria discovered they improve their migration routes year after year as they gain experience. Older is wiser when it comes to migration.
Back in 2013 researchers fitted more than 250 juvenile white storks with tracking devices that followed each bird as it traveled to its wintering and breeding grounds. As the individuals aged they learned shortcuts, used more direct routes, and moved faster in Spring even though it used more energy.
White storks mate for life and set up housekeeping at age 3 or 4. On the graph we can see that older birds — mated adults — were in a rush to get home but young birds with no nest to reclaim spent time dawdling and exploring.
This week the New York Times described A Feathered Murder Mystery at 10,000 Feet which I cannot resist retelling because peregrines are involved. My story will be in photos none of which are from the real episode. See actual photos and the full story at the link above.
In early 2023 scientists from the University of Amsterdam attached satellite trackers to eight black-bellied plovers that were wintering in the Netherlands (a.k.a. grey plovers, Pluvialis squatarola). The goal was to find out where they breed in the Arctic. Here’s what one looks like in spring.
In late May 2023 the birds were migrating northwest over Sweden at almost 10,000 feet when one of them abruptly changed direction 180 degrees, descended to near sea level and completely stopped moving. When a tracking device sends that kind of news, the bird is dead.
650 feet away from the abandoned tracker was a peregrine nest. (Chances are very good that the scientists did NOT visit during nesting season but the whitewash left on a cliff is a clear indication of who was there in late May.)
The plover died during peregrine breeding season when there were probably young peregrines in the nest so the father bird went hunting up where the food was flying.
It’s not a surprise that plovers fly so high — some species fly even higher on migration — but it is a surprise that peregrines hunt at 10,000 feet. The plover’s tracker provided the first documented evidence.
Just when we think we know everything about peregrines, they surprise us again.
p.s. Please keep in mind that none of these photos are from the actual event!
Though the current distribution of spotted lanternflies overlaps part of the blue headed vireo’s breeding range, an individual vireo might never have seen a lanternfly before he reached Central Park. This particular bird might be taking his first taste.
Spotted lanternflies at Herrs Island, Pittsburgh, 3 August 2024 (photo by Kate St. John)
How can a blue-headed vireo be naive about spotted lanternflies? It’s easy if he hatched this year. Let’s compare three maps.
1. This map of spotted lanternfly (Lycorma delicatula) distribution shows there are no lanternflies in the Adirondacks, Vermont, New Hampshire. Nor are they in Canada yet.
2. Blue-headed vireos (Vireo solitarius) breeding north of NYC nest in Canada, New England and New York state. The vast majority of hatch year blue-headed vireos were born north or outside of the lanternfly’s distribution.
3. Were these naive birds in Central Park this week? This eBird slideshow of blue-headed vireo abundance for the weeks of 18 and 25 October shows that most vireos have left Canada and are moving rapidly out of New York and New England. The bird in Central Park on 22 October was probably born outside the spotted lanternfly zone.
Blue-headed vireo, Weekly abundance, Week of 25 October (from eBird)
Blue-headed vireo, Weekly abundance, Week of 25 October (from eBird)
By now blue-headed vireos have already left southwestern PA and this week they’ll depart from eastern Pennsylvania. Their help with spotted lanternflies will have to wait until next year.
Nashville warbler, Frick Park, 20 Oct 2024 (photo by Charity Kheshgi)
23 October 2024
During fall migration birds are coming and going all the time. Some shorebirds pass through in August, September is warbler season, October is sparrow season, and November should be ducks. When we saw a Nashville warbler in Frick Park last Sunday, eBird squawked “That species has left already. Your bird is Rare! You have to justify it.”
In autumn Nashville warblers arrive in southwestern PA during the first week of September and are completely gone by 18 October. Charity Kheshgi’s photo on 20 October is proof that one still lingered.
Swainson’s thrushes have already come and gone, 13 September to 11 October
Remember when we saw a lot of Swainson’s thrushes a couple of weeks ago? Well, they breed in Canada and only visit the Pittsburgh area briefly on migration, approximately 13 September to 11 October (see the map animation).
Leaving soon: ruby-crowns, chipping and yellow-rumps will be (mostly) gone by 8 November.
This month we’re enjoying ruby-crowned kinglets, chipping sparrows and yellow-rumped warblers but eBird’s weekly abundance maps show that, except for stragglers, these three will leave southwestern Pennsylvania by 8 November. That’s why I was amazed the first time I saw ruby-crowned kinglets overwintering in eastern PA.
Ruby-crowned kinglet, Frick Park, 20 Oct 2024 (photo by Charity Kheshgi)Chipping sparrow, Oct 2012 (photo by Steve Gosser)Yellow-rumped warbler eating poison ivy berries in 2013 (photo by Cris Hamilton)
Here until 29 November:
Except for a few stragglers, most red-winged blackbirds will leave southwestern PA by the end of November. If you’re desperate to see one in the winter, visit northeastern Ohio near Akron.
Two evening grosbeaks in flight, western Washington State (photo from Wikimedia Commons)
14 October 2024
When North Americans go south for the winter they do it to escape the cold. When boreal finches leave Canada in autumn it’s not about cold, it’s about food.
Winter finches are cold hardy and could stay up north all year but when seed cones and fruit are in short supply they fly south to find food. Every year the Finch Network examines finch food crops across Canada and predicts southward movement by species. Their 2024-25 Winter Finch Forecast came out in late September, summarized below.
This winter we will NOT see these species.
Pine grosbeaks (Never come to southwestern PA anyway.)
Redpolls
White-winged crossbills
Red crossbills
Redpolls (It feels like a very long time since redpolls came to PA.)
Bohemian waxwings (Never come to southwestern PA anyway.)
This year, the majority should leave Canada with a likely moderate flight to the Great Plains and southern United States. … At feeders, they prefer black oil sunflower seeds.
Areas from Manitoba eastward affected by Spruce Budworm infestations have a poor cone crop. Siskins that bred in these areas will be on the move. While band recoveries show siskins will move straight across North America from coast to coast, there should be some small movement south in the eastern half of the United States this fall in search of food.
Evening grosbeak, January 2013 (photo by Steve Gosser)
Spruce budworms caused problems with the cone crop this summer but there were lots of berries. However, the berries gone now so…
Evening Grosbeaks should visit areas from the Maritime provinces south towards Pennsylvania. Areas even further south to the mid-Atlantic states may see grosbeaks this winter.
— 2024-25 Winter Finch Forecast
These species are not finches, but are part of the prediction.
In eastern North America westward to Manitoba the deciduous tree crop (they love acorns on oaks) appears below average with scattered areas of average crops, so expect a moderate to strong flight this fall.
Connecticut warbler banded at Hays Woods with engorged tick above eyering, 8 October 2024 (photo by Nick Liadis, Bird Lab)
9 October 2024
Yesterday while Bird Lab was at Hays Woods, Nick Liadis captured and banded a Connecticut warbler! I was not there to see this rare bird (alas) but Nick sent me a photo. Notice that the warbler has an engorged tick at top right of his eye-ring.
Tick season has returned with a vengeance after a low period during August and September’s drought. Because they cannot live without moisture ticks hang out in humid vegetation, but there was very little available during the drought. All that has changed with the recent rains and black-legged ticks are now active for their mating season which they conduct on the bodies of deer. I was reminded of this yesterday when I saw a deer in Schenley Park with three engorged ticks on its face. (Ewwww!)
Birds that forage on the ground are likely to encounter ticks so its no surprise that the Connecticut warbler and this song sparrow acquired them.
Immature yellow-bellied sapsucker near spotted lanternflies, Frick Park, 6 Oct 2024 (photo by Charity Kheshgi)
8 October 2024
Bird migration was intense over Pittsburgh on Friday night, 4 October, when more than 20,000 songbirds flew south overhead. We saw the results on Saturday morning in Frick Park where a new cohort of species had arrived with good news: Some of them were eating spotted lanternflies!
The new species included ruby-crowned kinglets, white-throated sparrows, yellow-bellied sapsuckers and yellow-rumped (myrtle) warblers. The mix was quite a change from September’s warblers.
Most of the new arrivals were feeding on tiny insects but the juvenile sapsucker, pictured above, was attracted to sweet lanternfly honeydew on ailanthus trees. He was too young to have ever seen a spotted lanternfly but he was curious. “Are these edible?”
Immature yellow-bellied sapsucker looking at spotted lanternflies, Frick Park, 6 Oct 2024 (photo by Charity Kheshgi)
Yes.
Perhaps the sapsucker got the idea from a northern cardinal that ate a lanternfly further down the trail. (I don’t have a photo of that incident; this one is from iNaturalist, New York.)
Yesterday afternoon a black tern (Chlidonias niger) made Allegheny County’s Rare Bird Alert when it was spotted at the main pond at Imperial. Immediately I thought of the black terns I’ve seen during spring migration at the Great Lakes with gorgeous black heads and bellies.
Black terns live in both the New and Old Worlds. The North American subspecies (C. n. surinamensis) spends the winter on the coasts of Central and South America. The Eurasian subspecies (C. n. niger) migrates across the Mediterranean and the Atlantic coast to Africa.
Bay-breasted warbler, Bird Lab banding at Hays Woods, 24 Sep 2024 (photo by Kate St. John)
28 September 2024
As I mentioned in Meet the Baypoll, I visited Bird Lab’sHays Woods banding station on Tuesday where I had up close looks at warblers and thrushes. Stars of the show were a bay-breasted warbler and a blackpoll captured in the same mist net. I got good photos of the bay-breasted warbler (Setophaga castanea) both front and back. I think he’s more confusing from the back.
Bay-breasted warbler, Bird Lab banding at Hays Woods, 24 Sep 2024 (photo by Kate St. John)
Bay-breasted and blackpoll warblers side by side, Bird Lab banding at Hays Woods, 24 Sep 2024 (photo by Nick Liadis)
Tuesday was a big day for Tennessee warblers (Leiothlypis peregrina). At least six were banded while I was there. They are hard to identify in autumn because so many of them are unremarkable immature birds without the classic dark olive back and gray head of breeding males. For example …
Tennessee warbler, Bird Lab banding at Hays Woods, 24 Sep 2024 (photo by Kate St. John)
… and another example, though this one has a dark olive back.
Tennessee warbler, Bird Lab banding at Hays Woods, 24 Sep 2024 (photo by Kate St. John)
During the banding process the bander fans the bird’s wings to look for its wing molt stage, a method for aging the bird. Here’s a close look at a Tennessee warbler’s wing.
Tennessee warbler in bander’s hand, wing fanned to examine molt, Bird Lab banding at Hays Woods, 24 Sep 2024 (photo by Kate St. John)
And finally, Tuesday was also a big day for Swainson’s thrushes (Catharus ustulatus). In the hand you can easily see the bird’s identifying feature, its buffy eye ring, but I was surprised by two things I’d never noticed before:
Swainson’s thrushes have a two-tone beak. The lower mandible is not as dark at the face as it is at the tip.
Swainson’s thrushes are small birds, though larger than warblers.
Swainson’s thrush, Bird Lab banding at Hays Woods, 24 Sep 2024 (photo by Kate St. John)
As I said before, if you’d like to see birds up close during fall migration, visit Nick Liadis’ Bird Lab website and scroll down to the list of three banding locations — Hays Woods, Upper St. Clair and Twin Stupas in Butler County — with instructions for contacting him to set up an appointment.
Learn more about Bird Lab on Wednesday 2 October when Nick Liadis presents Studying Migration Across a Landscape Gradient: Bird Banding in Urban, Suburban, and Rural Habitats at the Three Rivers Birding Club meeting at Beechwood Farms (and on Zoom).
Don’t forget to support Nick’s efforts with a donation at Bird Lab’s GoFundMe site.
Baypoll = Bay-breasted warbler (left) + Blackpoll warbler (right). photo by Nick Liadis, Bird Lab banding station at Hays Woods
26 September 2024
Two species of North America’s fall warblers are so easy to mistake for each other that the pair has gained a nickname. Meet the “baypoll.”
On Tuesday I visited Bird Lab’sHays Woods banding station for an up-close look at fall migrants. That morning Nick Liadis and Shana banded magnolia warblers, Swainson’s thrushes, Tennessee warblers, ovenbirds and many other species. Best Birds were the two pictured above, found in the same net at the same time: a bay-breasted warbler and a blackpoll warbler. Were they traveling together? Maybe. See yesterday’s blog.
These two species look so much alike in autumn that birders joke that they’ve seen a baypoll when they aren’t sure which one it is. Baypoll = BAY-breasted / blackPOLL. eBird doesn’t accept that designation, of course, but it’s useful for describing our frustration.
How can you tell the two apart?
In non-breeding plumage the bay-breasted warbler (Setophaga castanea) has bold wingbars with a dark bar between them and often, but not always, a faint bay (chestnut) wash on its flanks. It also has dark feet and an unstreaked breast. Compared to other warblers the bay-breasted looks long and bulky, not petite.
Blackpoll warblers (Setophaga striata) are striped, striata, where the bay-breasted is not. Even when the stripes are faint you’ll see them at the sides of the breast. Wingbars on blackpolls are pronounced but not as emphatic as on the bay-breasted. Blackpolls have a more definite eyeline than bay-breasted, but the real clincher for a blackpoll is its yellow-orange feet! The bird may have dark legs but it always wears golden slippers. I have spent many frustrating minutes waiting for a blackpoll to show me its feet.
Notice the feet on both birds in the top photo, sticking out above the bander’s thumb.
So next time you see a baypoll, check out its feet.
If you’d like to see birds up close during fall migration, visit Nick Liadis’ Bird Lab website and scroll down to the list of three banding locations — Hays Woods, Upper St. Clair and Twin Stupas in Butler County — with instructions for contacting him to set up an appointment.
