Emerging From The Deep

Climate Change, Water and Shore, Weather & Sky
Youghiogheny River dam with lake at normal level (photo from 1993 via Wikimedia Commons)

1 November 2024

In 1944 the US Army Corp of Engineers completed a flood control dam across the Youghiogheny River that created a lake into Maryland. The project included a new bridge for US Route 40 because the Great Crossings Bridge at Somerfield would be submerged and so would the town’s low lying streets and buildings.

map of Youghiogheny River Lake and Recreational Area from USACE via Wikimedia

Normally the lake is full and beautiful. You would never know there was a bridge underneath it.

Beautiful Youghiogheny River Lake (photo from recreation.gov)

But this year a drought in the Youghiogheny watershed has lowered the lake so far that you can walk out on the old Great Crossings Bridge.

video embedded from CBS Pittsburgh on YouTube

This Google Map shows both bridges.

embedded Google Map showing submerged Great Crossings Bridge north of US Route 40

Pittsburgh is not in severe drought so it’s hard to understand how this lake could drop unless you know where the river comes from. The Youghiogheny is a north-flowing river with headwaters in the mountains of West Virginia and Maryland. Notice that the rest of the Monongahela river basin starts in West Virginia as well.

Monongahela River Basin, Youghiogheny highlighted (map from Wikimedia Commons)

The headwaters of both the Youghiogheny and Monongahela have been in drought since early July. At this point the drought is Extreme to Exceptional in western Maryland and West Virginia.

Northeastern US Drought Map, 29 Oct 2024 (map from US Drought Monitor at UNL)

Water levels have dropped in both rivers but the Monongahela cannot afford to get too low because it carries a lot of barge and boat traffic.

Barge moving downstream on the Monongahela River at Duck Hollow, 18 Sep 2023 (photo by John English)

However, there is water upstream to feed the Monongahela. Releases from Youghiogheny River Lake have, in part, kept the Mon navigable.

And so the old bridge emerges from the deep.

p.s. This isn’t the first time the old bridge has been exposed.

There Was Once a Bat on Halloween

Books & Events, Mammals
Little brown bat in flight, Carondelet Park in Missouri, May 2017 (photo from Wikimedia Commons)

31 October 2024

On Halloween 2008 I came across a small bat roosting on a tree in Schenley Park, described in A Bat on Halloween. Every time I pass the tree, especially on Halloween, I look for a bat but the chances of finding one are slim to none.

Little Brown Bat clinging to an oak in Schenley Park on Halloween 2011 (photo by Kate St. John)

Little brown bats (Myotis lucifugus) used to be one of the most common bats in North America but their population in the Northeast has declined 90% since 2006 because of white nose syndrome (WNS), a disease caused by a European fungus that was accidentally introduced by cave explorers near Albany, NY.

The fungus spreads rapidly. It was confirmed county by county in southwestern PA in 2010, 2011 and 2012 and now it spans the continent. Little brown bats were listed as Endangered by the IUCN in 2021.

Where is WNS? (interactive map from whitenosesyndrome.org)

There are far fewer bats in Pennsylvania this Halloween than there were 16 years ago. It is unlikely that I will ever see a little brown bat in daylight again.

Read more about white nose syndrome at Another Alien Invader and whitenosesyndrome.org.

Older Is Wiser On Migration

Bird Behavior, Migration
White stork in flight, Huelva, Spain (photo from Wikimedia Commons)

30 October 2024

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.

White storks on migration at La Janda, Spain (photo from Wikimedia Commons)

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.

This graph from the PNAS study Learning shapes the development of migratory behavior shows how the storks’ efforts changed over time.

The influence of age on migration duration for white storks (Ciconia ciconia) that were born in southern Germany and tracked continuously from early life onward. — from “Learning shapes the development of migratory behavior” at PNAS

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.

White stork in flight, France (photo from Wikimedia Commons)

With age comes experience and changing priorities.

Older is wiser … and more driven.

Merlin versus Crow: How to Win a Nest

Bird Behavior, Birds of Prey, Crows & Ravens
Merlin, eastern US (photo by Wm.H. Majoros via Wikimedia Commons)
Merlin, eastern US (photo by Wm.H. Majoros via Wikimedia Commons)

29 October 2024

Last spring during the nesting season I was so distracted by peregrines that I neglected to check on a merlins’ nest reported in Highland Park. By the time I got over there the young had fledged, the merlins were gone, and a small group of American crows were inspecting the area and commenting on what they found.

Crows are intensely interested in merlin nests because those nests may have been stolen from crows.

Merlins (Falco columbarius) never build a nest. Instead they search for crow or hawk nests, ideally in conifers, and take them over. If the target nest is unoccupied no problem but merlins are feisty and will try for an active crows’ nest by driving off the incubating female crow. If harassing her doesn’t work, they shout at her all day until another predator shows up and forces her to leave.

This often works because merlins are loud and fearless. They’ll drive away anything that irritates them including this raven (a merlin predator not a competitor).

Merlin attack! Raven flips upside down, Renews, NL, 10 July 2010 (photo by Trina Anderson)
Merlin attack! Raven flips upside down, Renews, NL, 10 July 2010 (photo by Trina Anderson)

However, in southwestern Pennsylvania there are now two species of crows — American crows (Corvus brachyrhynchos) and fish crows (Corvus ossifragus) — and it makes a difference to the merlins’ success.

American crow and fish crow (photos from Wikimedia Commons)

A 2019 study presented at the Wilson Ornithological Society showed that if the merlin nest was successful, chances are the nest had been owned by American crows.

Merlin chicks in nest (photo from Wikimedia Commons)

Behavioral interactions between nest-parasitic Merlins (Falco columbarius) and nest-building Fish Crows (Corvus ossifragus) in a new zone of overlap explains that American crows and merlins have coexisted for millennia so they have forged a working relationship and can reach detente early on. One or the other cuts their losses and nests elsewhere.

Not so with fish crows. Merlins and fish crows are new to each other so they haven’t worked out their differences and continue harassing for a much longer period. Few or none on either side have a successful nest. In the study of 25 fish crow nests in upstate New York, 40% failed due to merlin interference. The study tracked 31 merlin nests and found 66% of those made in fish crow nests did not fledge young.

Autumn and winter are good times for seeing merlins and fish crows in Pittsburgh. It would be interesting to find them interacting in spring and watch what happens.

p.s. Thank you to Don Nixon of PA Merlins for alerting me to this fascinating topic. The paper(*) is by Connor O’H. Loomis and Anne B. Clark (Binghamton University), John Confer (Ithaca College), Kevin J. McGowan (Cornell Lab of Ornithology) but it is behind a pay wall. The fish crow and merlin nesting studies continue beyond 2019 in Ithaca, NY at Cornell Lab of Ornithology.

Yesterday at Duck Hollow

Books & Events, Phenology
Yesterday’s outing at Duck Hollow, 27 Oct 2024 (photo by Charity Kheshgi)

28 October 2024

Six of us went birding yesterday at Duck Hollow and we didn’t just stand around. Here we are on the move to look in the thickets.

Before the rest of us arrived, Claire Staples captured this image of sky, sun and fog on the Monongahela River at 7:55am.

Sky, sun, fog at Duck Hollow, 27 Oct 2024 (photo by Claire Staples)

As 8:36am the sky cleared a bit. Two contrails make dogleg turns to the north.

Sky and fog at Duck Hollow, 27 October 2024 (photo by Charity Kheshgi)

Our Best Bird skulked in a thicket, of course, but kept making noise. He soon became the most photographed bird of the day: a winter wren in shadow and then in the open.

Winter wren in shadow, Duck Hollow, 27 Oct 224 (photo by Jeff Cieslak)
Winter wren in the open periodically scolding, Duck Hollow, 27 Oct 2024 (photo by Charity Kheshgi)

Duck Hollow’s northern mockingbird is still present and noisy.

Northern mockingbird, Duck Hollow, 27 October 2024 (photo by Charity Kheshgi)

We found a bumper crop of honeysuckle fruit along the Lower Nine Mile Run Trail.

Bush honeysuckle fruit, Lower Nine Mile Run Trail, 27 Oct 2024 (photo by Kate St. John)

Unfortunately …

Invasive honeysuckle berries aren’t strictly bad for birds. They’re an easy food source when birds are in a pinch, but they’re kind of like junk food: Compared to native berries, they have less fat and nutrients that birds need to fuel their long-distance flights. 

— Audubon news: Mystery Solved: Invasive Berries to Blame for Turning Flickers’ Feathers Pink

Our “rare” bird of the day was a flock of 16 fish crows vocalizing as they flew. eBird didn’t believe we could find that many but eBird’s “rare” filter doesn’t know about, or cannot pointpoint, the fish crow phenomenon in Pittsburgh’s East End.

See our checklist of 27 species here https://ebird.org/checklist/S200489956 and below.

Duck Hollow, Allegheny, Pennsylvania, US
Oct 27, 2024 8:30 AM – 10:30 AM … 27 species

Canada Goose (Branta canadensis) 26
Mallard (Anas platyrhynchos) 11
Mourning Dove (Zenaida macroura) 3
Killdeer (Charadrius vociferus) 4
Great Blue Heron (Ardea herodias) 2
Belted Kingfisher (Megaceryle alcyon) 2
Red-bellied Woodpecker (Melanerpes carolinus) 1
Downy Woodpecker (Dryobates pubescens) 3
Northern Flicker (Colaptes auratus) 1
Blue Jay (Cyanocitta cristata) 10
American Crow (Corvus brachyrhynchos) 6
Fish Crow (Corvus ossifragus) 16 Flock heading south for the Waterfront shopping center, vocalizing on their way
Carolina Chickadee (Poecile carolinensis) 2
Golden-crowned Kinglet (Regulus satrapa) 1
Winter Wren (Troglodytes hiemalis) 1
Carolina Wren (Thryothorus ludovicianus) 2
European Starling (Sturnus vulgaris) 8
Northern Mockingbird (Mimus polyglottos) 1
American Robin (Turdus migratorius) 60
Cedar Waxwing (Bombycilla cedrorum) 30
House Finch (Haemorhous mexicanus) 13
American Goldfinch (Spinus tristis) 2
Dark-eyed Junco (Junco hyemalis) 4
White-throated Sparrow (Zonotrichia albicollis) 10
Song Sparrow (Melospiza melodia) 6
Yellow-rumped Warbler (Setophaga coronata) 10
Northern Cardinal (Cardinalis cardinalis) 10

Peregrine Caught Him at 10,000 Feet

Bird Behavior, Migration, Peregrines
Peregrine on the hunt, May 2022 (photo by Chad+Chris Saladin)

27 October 2024

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.

Black-bellied plover in breeding plumage (photo from Wikimedia Commons)

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.

Black-bellied plovers in flight in August (photo from Wikimedia Commons)

The scientists, led by Dr. M.P. (Chiel) Boom, went to Sweden to retrieve the tracker and found it on a ledge in an old quarry.

Old abandoned granite quarry, Rixö, Sweden (photo from Wikimedia Commons)

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.)

Peregrine near nest on Castle Cliff, UK (photo from Wikimedia Commons)

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!

Seen This Week: Autumn Colors

Phenology, Schenley Park, Trees, Weather & Sky
Fall color of pawpaw leaves, Schenley, 25 Oct 2024 (photo by Kate St. John)

26 October 2024

Fall color is so spectacular in Pittsburgh this week that many of us have been snapping pictures everywhere we go. Here are just a few of the colorful leaves and trees I’ve seen in town.

Pawpaw leaves are turning bright yellow in Schenley Park while Virginia creeper is red along the Three Rivers Heritage bike trail at Herrs Island.

Virginia creeper at Herrs Island back channel, 22 Oct 2024 (photo by Kate St. John)

Sunlight reflecting on the water made rippling lights in the trees on 22 October. It was so warm you can hear crickets.

Ripples in the trees, 22 Oct 2024 (video by Kate St. John)

Yesterday in Schenley Park the trees were yellow or red depending on species.

Scene on the Upper Trail, 25 Oct 2024 (photo by Kate St. John)
Scene on the Serpentine, 25 Oct 2024 (photo by Kate St. John)

Not to be outdone by autumn leaves, the sky turned orange at sunrise on Saturday.

Sunrise, 25 Oct 2024 (photo by Kate St. John)

Sunrise is after 7am now. We’ll “fix” that next weekend when we turn the clocks back.

Do Spotted Lanternflies Taste Good? Yes, Says a Vireo

Bird Behavior, Insects, Migration, Spotted Lanternflies
Blue-headed vireo eating insect in Missouri (photo from Wikimedia Commons)

25 October 2024

This week a migrating blue-headed vireo visiting New York City decided that spotted lanternflies taste pretty good.

If you don’t see the video above, click here: pic.twitter.com/t41vaByIp9

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.

Spotted lanternfly U.S. distribution as of 12 Sep 2024 (map by Cornell CALS via New York State Integrated Pest Management)

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.

Range map of blue-headed vireo (from Wikimedia Commons)

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.

slideshow of blue-headed vireo abundance from eBird Status and Trends

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.

The Future is Almost Here: When the Atlantic (AMOC) Circulation Fails

Climate Change, Water and Shore
Visualisation of the Gulf Stream stretching from the Gulf of Mexico to Western Europe (NASA image from Wikimedia)

24 October 2024

Yesterday I saw a video of a scientist choking up at the prospect of Atlantic Ocean circulation failing. Why is he sad?

(If you don’t see the video above, click on this link.)

The speaker is one of 44 climate scientists who released an open letter this week warning that by 2050 a tipping point will likely cause the Atlantic Meridional Overturning Circulation (AMOC) to fail, making northeastern Europe much colder and ushering in a host of other adverse effects. He is from Britain and 2050 is just 26 years away.

The Atlantic Meridional Overturning Circulation (AMOC) is the main ocean current system in the Atlantic Ocean and a major component of Earth’s ocean circulation. It transports heat and salinity northward and returns cold water to the south. —- paraphrased from Wikipedia

Ocean thermohaline circulation with AMOC extent marked in black. Future failure zone in yellow (from Wikimedia)

Climate scientists have been studying AMOC for decades because they realize that as Greenland melts, it dumps freshwater into the North Atlantic. The freshwater influx slows the northern end of the AMOC and that messes up the whole system.

We (Americans) haven’t paid much attention to this because we think it will only affect Europe but “messing up the whole system” will change the planet completely. Adverse effects include:

  • Northeastern Europe will get much colder
  • A new Ice Age will begin so the entire Northern Hemisphere, ourselves included, will get colder. See Warming Up to the Next Ice Age.
  • The Gulf Stream won’t transport water away from North America (the far end is chopped off) so, within a matter of years, sea level will rise one-to-three feet on the East Coast.
  • The tropical rain belt will move south, disrupting wet and dry seasons in the Amazon and Africa.

This 13-minute video from PBS describes what AMOC is, how it affects us, and what will go wrong when it fails.

2023 video embedded from PBS Terra on YouTube

For a relatively quick synopsis, see The Guardian: ‘We don’t know where the tipping point is’: climate expert on potential collapse of Atlantic circulation.

Birds Coming and Going

Migration
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).

Swainson’s Thrush (photo by Chuck Tague)
Swainson’s thrush weekly abundance throughout its range (animation from eBird)
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.

Red-winged blackbirds foraging on the surface of a pond (photo from Wikimedia Commons)
Golden-crowned kinglets, white-throated sparrows and dark-eyed juncos are winter birds.

According to eBird’s weekly abundance maps:

  • Golden-crowned kinglets arrive by 4 October and leave by 26 April.
  • White-throated sparrows arrive around 1 October and leave in the first two weeks of May.
  • Dark-eyed juncos get here 25 October and leave by 26 April. (I’ve seen a few already.)
Golden-crowned kinglet, Frick Park, 7 Nov 2023 (photo by Charity Kheshgi)
White-throated sparrow, white-striped color morph (photo from Wikimedia Commons)
Dark-eyed junco (photo by Cris Hamilton)

Watch dark-eyed juncos come and go in this eBird weekly animation.

Dark-eyed junco weekly abundance map (animation by eBird)