Category Archives: Migration

We Like to Travel Together

Migration
Magnolia warbler and American restart (photos by Steve Gosser)

23 September 2024

This month warblers and thrushes are making long journeys from North America to Central and South America. Every week there’s a new cohort of species and some species pass through at the same time.

Lately I’ve noticed that when I find lots of American redstarts there are also many magnolia warblers. When I find Tennessee warblers there are often Nashville and black-throated green warblers as well.

Nashville, Tennessee and black-throated green warblers travel together (photos by Charity Kheshgi and Cris Hamilton)

Bird banders wondered about this phenomenon, too, so five banding stations including Powdermill Avian Research Center gathered 20+ years of banding data for a long term study of spring and fall migration. They grouped the banding data by season, by mist net and the date-time each bird was captured, and by species. When they examined which species were found together patterns emerged, published in their study Persistent species relationships characterize migrating bird communities across stopover sites and seasons.

Two species captured in the same net at the same time, over and over for a period of 20 years, indicates they are feeding together at stopover sites and are likely traveling together, too.

The study’s chart of fall migrants shows that American redstarts (AMRE) and magnolia warblers (MAWA) are often found together during fall migration (the thick red line). So are Tennessee warblers (TEWA), Nashville warblers (NAWA) and black-throated green warblers (BTNW). [See chart of 4-letter bird banding codes used in the diagram.]

Fall migration chart from Persistent species relationships characterize migrating bird communities across stopover sites and seasons

There’s even a correlation among thrushes. Notice the faint line between Swainson’s thrushes (SWTH) and gray-cheeked thrushes (GCTH), above.

Swainson’s and gray-cheeked thrushes (photos by Steve Gosser and Charity Kheshgi)

This fall I noticed that while many Swainson’s thrushes are traveling through southwestern Pennsylvania I’ve also seen a sprinkling of gray-checked thrushes. The line on the chart is probably faint because gray-cheeked thrushes are far less numerous than Swainson’s.

So who does this blackpoll warbler travel with? His traveling buddy is not on the chart but I can guess.

Blackpoll warbler, Sept 2012 (photo by Marcy Cunkelman)
Blackpoll warbler, Sept 2012 (photo by Marcy Cunkelman)

I’ll bet he travels with bay-breasted warblers. Can you say baypoll?

Read about the study in Audubon Magazine: A New Study Reveals Migration Isn’t a Solo Affair—It’s the Social Event of the Season.

See the full study in PNAS: Persistent species relationships characterize migrating bird communities across stopover sites and seasons.

Refueling on Migration

Migration, Plants & Fungi
Cape May warbler on Devil’s Walking Stick look-alike: Japanese angelica, 6 Sept 2023 (photo by Dave Brooke)

19 September 2024

During my recent journey in southern Spain I appreciated the opportunity to rest and refuel.

This month warblers are making their own long journey at night to Central and South America. When convenient they stop during the day in Pennsylvania to refuel on the fruit in our parks and gardens and on the insects that crawl on the fruit.

Seven years ago I wrote about what attracts them to stopover in our city parks. This vintage article is updated to reflect the real name of their favorite fruit in Frick Park.

Fruits On Migration

More Than a Hawk Watch

Migration, Southern Spain, Travel
Black stork in flight, Algeria (photo from Wikimedia Commons)

12 September 2024: Day 6, Tarifa and birding at the Strait of Gibraltar, WINGS Spain in Autumn. Click here to see (generally) where I am today.

At U.S. hawk watches we track vultures, hawks, eagles, falcons and kites but rarely record other species at the official HawkCount.org. That is not the case at Tarifa where fall migration includes a total of 150,000 white storks (Ciconia ciconia) + black storks (Ciconia nigra).

This short video is the slow motion passage of four raptors. I am not sure of the first one but the others are two booted eagles (Hieraaetus pennatus) and an Egyptian vulture (Neophron percnopterus).

video embedded from Birding The Strait, Tarifa

Watch as huge numbers of soaring birds wait to cross the Strait. Notice the sound track! It is WINDY!

video embedded from Per Stensland on YouTube

Birding at the Strait is more than watching hawks.

p.s. We had a great morning on 10 September at Algarrobo hawk watch with thousands of hawks and eagles plus alpine & common swifts, four black storks, and 22 European bee-eaters.

Seen This Week: Warblers and Late Summer Flowers

Deer, Migration, Phenology, Plants & Fungi
Black-throated green warbler, Frick Park, 14 Aug 2024 (photo by Charity Kheshgi)

17 August 2024

This was a week of still-nesting swallows, pretty flowers, migrating warblers, and many, many deer in the city parks.

Moraine State Park, 11 August. Charity Kheshgi and I were surprised to see cliff swallows still nesting on 11 August at the Rt 528 Boat Launch area. Parents were feeding young at four to five nests.

Cliff swallows with young in nest, Moraine State Park, 11 Aug 2024 (photo by Charity Kheshgi)

Late summer flowers: Best photos this week are butter-and-eggs (non-native), spreading dogbane and blue vervain.

Butter and eggs, in the snapdragon family, Southside Riverfront Park, 12 August (photo by Kate St. John)
Spreading dogbane, Moraine State Park, 11 August 2024 (photo by Kate St. John)
Blue vervain, Southside Riverfront Park, 12 August (photo by Kate St. John)

Warblers at Frick Park: On 14 August Charity Kheshgi and I saw a good flock of warblers on Trough Trail. Blackburnians were still considered rare on the 14th (too early for them) but we found five! Here’s one eyeing a bug on Japanese angelica, a devil’s walking stick look-alike.

Blackburnian warbler, Frick Park, 14 Aug 2024 (photo by Charity Kheshgi)

We recognized distinctive plumage on each of the 5 Blackburnians. As if to prove there were so many, three posed in one shot.

3 Blackburnian warblers in one shot, Frick Park, 14 Aug 2024 (photo by Charity Kheshgi)

We also saw one immature chestnut-sided warbler hanging out in the flock.

Immature chestnut-sided warbler, Frick Park, 14 Aug 2024 (photo by Charity Kheshgi)

Deer: Schenley and Frick Parks, 14 and 16 August

It was a big week for deer in the city parks. I saw 10 in Frick on Wednesday, and 9 in Schenley on Friday. Of the 9, more than half were young or spotted fawns that were born this year. If my tally is representative, the Schenley deer population has doubled itself in just one year.

3 deer in Frick Park, 14 Aug 12024 (photo by Kate St. John)

I believe that the doe in this photo is shedding her summer fur (rusty color) to switch to her winter coat (gray-brown).

Spotted fawn with doe in Schenley, 16 Aug 12024 (photo by Kate St. John)
2 of the 9 deer seen in Schenley on 16 August 2024 (photo by Kate St. John)

Why are deer so easy to see in Schenley Park? Because there is no underbrush to hide them. There are so many deer that they ate all the underbrush. So there’s nowhere to hide.

p.s. The green grass in the photo is Japanese stiltgrass, a plant that deer don’t eat.

Swarms of Swallows

Bird Behavior, Migration, Songbirds
Tree swallow (photo from Wikimedia Commons)

12 August 2024

On Friday I wrote about a swarm of dragonflies. Today it’s a swarm of swallows.

On 31 July my sister watched more than two dozen tree swallows swarm over her yard in Tidewater Virginia. They were feasting on flying bugs for about 20 minutes, and then they were gone.

After they finish breeding, tree swallows (Tachycineta bicolor) gather in ever-growing flocks in July and August and begin their southward migration. In transit they seek out swarms of insects that may include true flies (Diptera), dragonflies and damselflies (Odonata).

Peak tree swallow migration occurs in early to mid-fall. I was at Cape Cod on 1 October 2017 when I witnessed a huge flock at West Dennis Beach. Abundant bugs attracted the tree swallows; abundant swallows attracted a falcon who captured one in his talons (top right of photo below).

Thousands of tree swallows and one falcon with prey, West Dennis Beach, MA, 1 Oct 2017 (photo by Kate St.John)
Thousands of tree swallows and one falcon with prey, West Dennis Beach, MA, 1 Oct 2017 (photo by Kate St.John)

On 6 October 2021, Mike of Mike’s Nature Connection witnessed a similar flock on Cape Cod.

video embedded from Mike’s Nature Connection on YouTube

If you live in the Mississippi or Atlantic flyways, or at their wintering grounds in Florida or Louisiana, there’s still time to see swarms of tree swallows. Watch their annual movements in this weekly abundance animation from eBird.

Tree Swallow Weekly Abundance throughout its range (animation from eBird)

See this map for yourself at eBird Status and Trends > Tree Swallow > Weekly Abundance.

Roost Rings on Radar

Bird Behavior, Migration
Animation of base reflectivity showing roost rings, 2 Aug 2010, 6:10 AM to 7:17 AM (image from NWS Wilmington, OH)

16 September 2024

Our largest swallow, the purple martin (Progne subis), has a very short breeding period in North America. In Pennsylvania they arrive in late April and fledge young in mid July.

Purple martins at Bob Allnock’s in Portersville, PA, July 2016 (photo by Kate St. John)

As soon as the fledglings fly well, adults and young leave the nesting area and spend their nights in a communal roost.

Flocking begins as soon as nestlings fledge; birds of all ages assemble in roosts before fall departure. This may represent nonbreeding activity rather than a specific response to upcoming migration, because the species is highly social and flocks in large roosts throughout the overwintering period. 

— Birds of the World: Purple Martin

Since the breeding period is earlier in the South, roosts in the Carolinas fill up in July and contain so many birds that their early morning departure can be seen on weather radar. This happened last week in Wilmington, North Carolina.

Facebook post from NWS Wilmington, NC on 12 July 2024

The same phenomenon happens at our latitude in August, as shown on radar in Wilmington, Ohio at top.

Learn more about purple martin roost rings in this article from Wilmington Ohio: Roosting Birds Detected By NWS Doppler Radar and this one from Wilmington, North Carolina: Purple Martin Roost Rings on Doppler Radar.

Unusual Visitor at Harrison Hills Park

Migration, Water and Shore

7 July 2024

Yesterday morning Mike Fialkovich found a juvenile yellow-crowned night heron at Harrison Hills County Park. The bird was easy to find in a shallow creek by the Creekside Trail head at Overlook parking lot. By the end of the day 11 eBirders had stopped by to see this unusual visitor. Here’s the bird at dusk.

Yellow-crowned night herons (Nyctanassa violacea) specialize in eating crabs and crayfish, especially at night. They are usually found in salt marshes, forested wetlands, swamps and on coastal islands but they’re not worried about people and will show up on lawns in Florida.

As you can see from their range map, their stronghold is in Central and South America where they live year round. From there this southern visitor is expanding north.

Yellow-crowned night heron range map embedded from All About Birds

Adults explore out of range in the spring.

Yellow-crowned night heron, Cuba (photo from Wikimedia Commons)

Juveniles wander widely, especially in August and September. It seems too early for a youngster to wander up the Mississippi and Ohio Valleys as far as Harrison Hills but yellow-crowned night herons retain juvenile plumage for three years so this bird might not be as young as we think.

And he’s not the first unusual visitor. This yellow-crowned visited in Duquesne in August 2019 and stayed for a week. Maybe this year’s bird will stick around for a while.

Yellow-crowned night heron in Duquesne, PA, 18 Aug 2019 (photo by Amy Henrici)

Sounds Like A Bug

Migration, Songbirds
Clay-colored sparrow singing in Minnesota (photo by Lorie Shaull via Flickr Creative Commons license)

25 June 2024

Today I’m with a group of friends looking for a bird that sounds like a bug in Clarion County, PA.

We’re at Piney Tract, State Gamelands 330, where we expect to hear — and maybe see — grasshopper, field, Henslow’s and song sparrows.

Piney Tract, Clarion County, 1 June 2017 (photo by Kate St. John)
Piney Tract, Clarion County, 1 June 2017 (photo by Kate St. John)

Many grassland sparrows sound like bugs — hence the name “grasshopper” sparrow — but the bird we’re looking for is a clay-colored sparrow (Spizella pallida) who sounds like this:

This bird is special because he’s outside his normal range.

Range map of clay-colored sparrow (image from Wikimedia Commons)

Here’s one in North Dakota.

Clay-colored sparrow in North Dakota (photo from Wikimedia Commons)

Dan Mendenhall saw the bird last Friday so we stand a good chance of finding it. See Dan’s photo here.

Seen This Week: Warblers and Tulips in the Trees

Insects, Migration, Trees, Weather & Sky
Blackpoll warbler, Presque Isle, 12 May 2024 (photo by Charity Kheshgi)

18 May 2024

Best birds this week were seen at Presque Isle State Park on Sunday 12 May while birding with Charity and Kaleem Kheshgi. At Leo’s Landing many of the birds were at eye level including this blackpoll warbler and the barn and bank swallows.

Barn and bank swallows, Presque Isle, 12 May 2024 (photo by Charity Kheshgi)

Even the treetop birds, like this yellow-throated vireo, cooperated for photographs.

Yellow-throated vireo, Presque Isle, 12 May 2024 (photo by Charity Kheshgi)

Was this redstart was looking askance at us? Or eyeing a bug?

American redstart, Presque Isle, 12 May 2024 (photo by Charity Kheshgi)

I had high hopes for the Bird Banding at Hays Woods on Wednesday 15 May but we were in for a surprise. No birds to band! Bummer. 🙁 This restart, banded earlier in the week, shows what we could have seen.

American redstart at Bird Lab banding (photo by Kate St. John)

After we left the banding station we had good looks at a scarlet tanager and found this Kentucky flat millipede (Apheloria virginiensis). It’s colored black and orange because it’s toxic.

  • It secretes cyanide compounds as a defense. Don’t touch it!
  • You might find one perched and dying on top of a twig. That’s because it can host the parasitic fungus Arthrophaga myriapodina which causes infected individuals to climb to an elevated spot before death (per Wikipedia). Eeeew.
Centipede Aphelosia virginiensis, Hays Woods, 15 May 2024 (photo by Kate St. John)

This week there were flowers in the tulip trees (Liriodendron) obscured by thick leaves. This flower came into view when a squirrel bit off the twig and didn’t retrieve the branch.

Tulip tree flower and leaves, 16 May 2024 (photo by Kate St. John)

Instead of rain on Wednesday we had a beautiful sunrise.

Sunrise 14 May 2024 (photo by Kate St. John)

To make up for no rain on Wednesday it’s pouring right now on Saturday.

Don’t Miss These Birds!

Migration, Songbirds

7 May 2024

If you’re wondering whether to go birding, don’t wait! Spring migration has been exceptionally good in the past few days migration. The slideshow, above, shows just a few of the 58 species Charity Kheshgi and I saw at Schenley and Frick Parks on Sunday 5 May.

The birds are here right now and they’re fairly easy to see despite the early leaf cover. They’re on the move. Don’t miss them. It’s time to get outdoors!

p.s. Did you notice that the first two birds in the slideshow are “Nashville” and “Tennessee” ?

(photos by Charity Kheshgi)