Category Archives: Water and Shore

Greater and White-Fronted

Greater white-fronted geese from Crossley ID Guide to Eastern Birds (image form Wikimedia Commons)

28 November 2022

Over the Thanksgiving weekend 6 greater white-fronted geese (Anser albifrons) showed up in western Pennsylvania — four in Lawrence County and four in Armstrong County.

Though they breed in the arctic around the world, the North American population stays west of the Mississippi. These geese are rare in Pennsylvania.

Range map of greater white-fronted goose embedded from

Their “greater” and “white-fronted” adjectives don’t make much sense unless you know the species they resemble in Europe.

They are “greater” because they are larger than the lesser white-fronted goose (Anser erythropus) that occurs only in Eurasia and is now Vulnerable to extinction.

They are “white-fronted” because they have white feathers on their faces surrounding their beaks, a field mark that distinguishes them from the similar greylag goose (Anser anser), another Eurasian species.

Greater white-fronted goose (detail from the Crossley ID Guide Eastern Birds, arrow added to indicate white front)

Only a handful of greater white-fronted geese are seen in western Pennsylvania in any given year, and then only in late October through early March.

If you see a goose that resembles this one check its field marks carefully. It may be an odd domestic goose, described here:

(images from Wikimedia Commons, map embedded from

Late November Birds at Duck Hollow

Ring-billed gull and common merganser, Duck Hollow, 23 Nov 2022 (photo by Charity Kheshgi)

26 November 2022

This week Charity Kheshgi and I saw ring-billed gulls (Larus delawarensis), a common merganser (Mergus merganser) and a few pied-billed grebes (Podilymbus podiceps) at Duck Hollow. All three species visit the Monongahela River in November when freshwater freezes up north.

Pied-billed grebe in silhouette, Duck Hollow, 23 Nov 2022 (photo by Charity Kheshgi)

The common merganser gave us an opportunity to mentally compare her field marks to a similar bird. Here are some tips.

Female common and red-breasted mergansers are so similar that it takes some practice to tell them apart. Charity’s photos show the common merganser’s two unique field marks:

  • A sharp demarcation between dark head versus white breast / gray back.
  • A sharply defined white under-chin.

Notice the common merganser field marks in three photos.

Common mergansers at Duck Hollow, 16 Nov 2022 (photo by Charity Kheshgi)
Common merganser, not showing its crest, Duck Hollow, 16 Nov 2022 (photo by Charity Kheshgi)
Common mergansers — unique field marks in blue (photo by Charity Kheshgi)

Female red-breasted mergansers (Mergus serrator) lack those sharp lines. The colors blend from one to the other.

Red-breasted merganser (photo from Wikimedia Commons)

Note that the presence of a head crest is not a reliable difference between the two; both can display it.

So here’s a quiz: Which species is in the photo below? Are these common or red-breasted mergansers?

Which merganser is this? (photo from Wikimedia Commons)

p.s. Location, location, location! Of the two species, common mergansers are inland birds more likely in Pittsburgh in November. Red-breasted mergansers concentrate at the coasts and Great Lakes in winter.

(photos by Charity Kheshgi and red-breasted mergansers from Wikimedia Commons)

Eagles Die When We Kill a Weed

Bald eagle portrait (photo from Wikimedia Commons)

6 November 2022

In 1994 dozens of bald eagles were found convulsing, dead or paralyzed near Arkansas’ DeGray Lake. Autopsies revealed the eagles died of a new disease called avian vacuolar myelinopathy (VM) that manifests as brain lesions. The dying spread to Florida, Georgia, the Carolinas and Texas (hashed areas on the map below) and continues to this day. In 2021 scientists discovered what causes VM. It’s a chain of events that begins when we use an aquatic weed killer to control an invasive weed.

VM occurs in watersheds where A. hydrillicola colonizes H. verticillata. Watersheds where VM has been diagnosed (indicated by black crosshatching). Watersheds where H. verticillata has been confirmed to be colonized with A. hydrillicola are shown in red, and watersheds where A. hydrillicola has not yet been observed on H. verticillata are shown in yellow. Watersheds not yet screened for A. hydrillicola, but where H. verticillata occurs, are shown in green. This map, embedded from NIH, is current to fall 2019.

The invasive weed is hydrilla (Hydrilla verticillata) that spreads easily and clogs waterways. It’s a huge problem in many southeastern states, especially in Florida.

Hydrilla at Lake Seminole, Florida (photo from Wikimedia Commons)

Hydrilla hosts a cyanobacteria called Aetokthonos hydrillicola which does not produce toxins by itself(*). However when it comes in contact with bromide-containing aquatic weed killer, meant to kill hydrilla, it produces a neurotoxin.

Cyanobacterium on hydrilla produces a neurotoxin in the presence of bromide weed killers (subimage from diagram below + jug composed from spare parts)

Fish and waterbirds, including American coots, eat the hydrilla and consume the neurotoxin. Soon they develop VM brain lesions.

American coot eating hydrilla (photo from Wikimedia Commons)

Bald eagles and other predators eat the fish and coots, often preying on sick ones because they are easy to catch.

Bald eagle hunting an American coot (photo from Wikimedia Commons)

And so bald eagles develop brain lesions and die of vacuolar myelinopathy.

The AVM cycle begins with a cyanobacteria on hydrilla that develops a neurotixin when treated with bromide weed killer (diagram from Wikimedia Commons)

The way to stop the dying is described in this NIH article Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy:

Integrated chemical plant management plans to control H. verticillata should avoid the use of bromide-containing chemicals (e.g., diquat dibromide). [The neurotoxin] AETX is lipophilic with the potential for bioaccumulation during transfer through food webs, so mammals may also be at risk.

— from NIH: Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy

Thus if you use a bromide-containing chemical (e.g. diquat dibromide) to control hydrilla you will unintentionally kill bald eagles.

Diquat aquatic weed killer contains bromide which leads to AVM (image constructed by Kate St. John)

Other solutions for controlling hydrilla without herbicide are highlighted in Florida Today (article and video): Melbourne-Tillman harvests hydrilla to avoid herbicides.

Meanwhile bald eagles aren’t out of the woods yet because we don’t know how long it will take for the neurotoxins to clear from infected lakes.

For more information see the article that inspired this topic: Science Magazine: Mysterious eagle killer identified: A new species of cyanobacteria that lives on invasive waterweed produces an unusual neurotoxin.

(photos and diagram from Wikimedia Commons, map embedded from NIH; click on the captions to see the originals)

(*) The mystery was solved when scientists discovered that the toxin came from bromides that did not occur naturally. From NIH, Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy: “Laboratory cultures of the cyanobacterium, however, did not elicit VM. A. hydrillicola growing on H. verticillata collected at VM-positive reservoirs was then analyzed by mass spectrometry imaging, which revealed that cyanobacterial colonies were colocalized with a brominated metabolite. Supplementation of an A. hydrillicola laboratory culture with potassium bromide resulted in pronounced biosynthesis of this metabolite. H. verticillata hyperaccumulates bromide from the environment, potentially supplying the cyanobacterium with this biosynthesis precursor.”

Rare in Time or Place

Greater yellowlegs, Duck Hollow, 30 Oct 2022 (photo by Lisa Kaufman)

31 October 2022

Birds are considered rare when they show up at a time or place that’s unusual for them. The rarest are the birds out of place, two of which we saw yesterday at Duck Hollow.

The surf scoter (Melanitta perspicillata) first seen at Duck Hollow by John Flannigan on 26 October was still present on the 30th. Autumn is the right time of year to find a surf scoter migrating through Pennsylvania but Pittsburgh is a rare place to find one. Surf scoters nest in Alaska and northern Canada and spend the winter at the coasts.

We saw the scoter yesterday drifting downstream beyond the Homestead Grays Bridge in a view similar to Michelle Kienholz’s photo below. This dark and distant duck with a ‘Roman nose’ and some white on its head/face was a Life Bird for many in the group. (Click here for a better photo by Justin Kolakowski.)

Surf scoter at Duck Hollow, 26 Oct 2022, 5:44pm (photo by Michelle Kienholz)

Our favorite rare bird of the day was the greater yellowlegs (Tringa melanoleuca) that we heard before we found him. Greater yellowlegs had never been recorded at Duck Hollow in autumn and rarely show up in Allegheny County even in spring. They nest in Canada and Alaska and spend the winter near the US southern coasts and in Central and South America.

When we heard his call (similar to audio below) we went down to the shore to find him.

Greater and lesser yellowlegs are similar but our bird’s vocalization, his slightly upturned beak and his behavior were diagnostic.

Generally walks with high-stepping gait; occasionally runs with neck extended. Movements rapid and jerky.

Birds of the World, Greater Yellowlegs

Lisa Kaufman took many photos of him.

The Duck Hollow outing was a success even though we saw only 21 species. Here’s our list.

Duck Hollow, Allegheny, Pennsylvania, US
Oct 30, 2022 8:30 AM – 10:30 AM
Protocol: Traveling, 1.0 mile
21 species, 9 participants.

Canada Goose (Branta canadensis) 2
Mallard (Anas platyrhynchos) 12
Surf Scoter (Melanitta perspicillata) 1 Continuing bird, drifting down stream when we saw it
Common Merganser (Mergus merganser) 5
Killdeer (Charadrius vociferus) 2
Greater Yellowlegs (Tringa melanoleuca) 1 photos by participant Lisa Kaufman
Belted Kingfisher (Megaceryle alcyon) 1
Red-bellied Woodpecker (Melanerpes carolinus) 3
Downy Woodpecker (Dryobates pubescens) 2
Blue Jay (Cyanocitta cristata) 2
American Crow (Corvus brachyrhynchos) 1
Carolina Chickadee (Poecile carolinensis) 5
Golden-crowned Kinglet (Regulus satrapa) 1
White-breasted Nuthatch (Sitta carolinensis) 1
Carolina Wren (Thryothorus ludovicianus) 5
American Robin (Turdus migratorius) 16
Cedar Waxwing (Bombycilla cedrorum) 4
White-throated Sparrow (Zonotrichia albicollis) 11
Song Sparrow (Melospiza melodia) 2
Yellow-rumped Warbler (Setophaga coronata) 4
Northern Cardinal (Cardinalis cardinalis) 5

View this checklist online at

(photos by Lisa Kaufman and Michelle Kienholz)

Dolphins Shed Their Skin Every 2 Hours

Dolphin playing in the wake, Everglades (photo from Wikimedia Commons)

16 October 2022

Dolphins have specialized skin for their underwater lives. The outer layer (epidermis) feels rubbery and is 15 to 20 times thicker than our own. It stays smooth because:

Dolphin skin constantly flakes and peels as new skin cells replace old cells. A bottlenose dolphin’s outermost skin layer may be replaced every 2 hours. This sloughing rate is 9 times faster than in humans. This turnover rate ensures a smooth body surface and probably helps increase swimming efficiency by reducing drag (resistance to movement). Bottlenose dolphin characteristics

Dolphins will even take turns to rub their bodies on corals and sponges, an activity that probably feels good. (video: Why Taking Turns Is Good for Dolphin Skin)

We know these things about dolphins because some have a close association with humans. Veterinarians and trainers take an active interest in the welfare of animals in their care.

Dolphin looking above the water, Kyoto Aquarium (photo from Wikimedia Commons)

Dolphin veterinarians are especially concerned that as dolphins age, their heart health may suffer. This includes the dolphins in the U.S. Navy’s Marine Mammal Program in San Diego.

Photo from 2003: Dolphin wearing geolocator during mineclearance operations, US Navy Marine Mammal Program (photo from Wikimedia Commons)

Last year the Navy asked for proposals to place heart monitors on their aging dolphins to unobtrusively monitor them as they move about in the ocean. There are many challenges to doing so including the dolphins’ skin. Because the skin turns over every two hours nothing can stick to it for long. I wouldn’t know about their skin if I hadn’t heard about the heart monitors.

The vast majority of us rarely if ever seen dolphins in the wild and know very little about their lives. We are mesmerized when we see them this close.

Fascinated by dolphins, Dolphin Bay (photo from Wikimedia Commons)

It’s hard not to love them.

(photos from Wikimedia Commons and from Royal Society Publishing; click on the captions to see the originals)

Eiders In Eclipse

Male common eider in eclipse plumage (photo from Wikimedia Commons)

28 September 2022

In September large, dark brown sea ducks swim in rafts off the coast of Maine. When they aren’t resting on the water they dive for mussels and crustaceans or walk up on the rocks to stand among the seaweed.

Common eiders on seaweed rocks (photo from Wikimedia Commons)

They vaguely resemble the lead field guide pictures for common eider (Somateria mollissima) but their current plumage is motley and variable. Right now common eiders are in eclipse.

Like many ducks and geese, eiders completely molt their tail and wing feathers after the breeding season, rendering them flightless for 3-4 weeks. Flight is restored in time for fall migration, but then they molt their body feathers. All told the process takes 4+ months.

To see eiders in all their glory watch them in breeding plumage from January to early June.

Male and female common eiders in breeding plumage (photo from Wikimedia Commons)

And you’ll see them fly.

Male common eider running to take off, April, East Sussex UK (photo from Wikimedia Commons)

(photos from Wikimedia Commons; click on the captions to see the originals)

Lobster Off the Menu to Save Right Whales

Rescuers work to cut the lines from an entangled right whale, Feb 2014 (photo by Florida Fish and Wildlife Conservation Commission, taken under NOAA permit 20556-01)

14 September 2022

A 6 September 2022 press release announced explosive news for the state of Maine: Lobster should be off the menu to save right whales.

Today the Monterey Bay Aquarium Seafood Watch program added more than a dozen fisheries, including the U.S. American lobster fishery, to its “Red List” of seafood because they currently pose risks to the survival of critically endangered North Atlantic right whales. Seafood Watch provides recommendations for seafood buyers based on sustainability criteria. … [Currently] more than 25,000 restaurants, stores, and distributors — including Whole Foods, Blue Apron, HelloFresh, Cheesecake Factory, Compass Group, and ARAMARK — have committed to using Seafood Watch ratings to guide purchasing and menu choices and to avoid red-listed seafood.

Press Release from

Mainers reacted angrily. Sadly this clash could have been avoided but instead it unfolded like a slow motion train wreck for at least 20 years. Here’s how we got to this point.

North American right whales (Eubalaena glacialis) are critically endangered with only about 340 remaining on Earth of which only 80 are female. The whales reproduce so slowly that more than one human-caused female death per year will send them to extinction.

Since at least 2001 NOAA Fisheries, which sets rules to protect fisheries and marine wildlife, has known that the second leading human cause of right whale deaths is from entanglement in vertical-hanging fishing gear including gillnets and the ropes of fish and lobster traps.

Illustration of gillnet (image from Wikimedia Commons)
Fishing ropes in Maine (photo by Susan Bell via Flickr Creative Commons license)

The ropes and lines become embedded in the skin. The gear snags more gear and prevents the whale from diving or surfacing completely. The whale dies.

To give you an idea of the threat to right whales read about the entangled mother “Snow Cone” and her calf last January of the coast of Florida.

Entangled right whale “Snow Cone” with her newborn calf, Jan 2022 (photo by Florida Fish and Wildlife Conservation Commission, taken under NOAA permit 20556-01)

Whenever possible rescuers from the Coast Guard and Florida Fish and Wildlife sail out to cut the lines from entangled right whales (photos at top in 2014 and below in 2004) but a portion of rope usually remains with the whale because it’s embedded in a wound.

Right whale entangled in gear off the coast of Florida in 2004, Coast Guard to the rescue (photo from Wikimedia Commons)

Meanwhile NOAA did not make rules for vertical-hanging gear to protect the whales, nor did the State of Maine. Eventually the procrastination caught up to NOAA. “In June, a court ruled that NOAA Fisheriesviolated both the Endangered Species Act and the Marine Mammal Protection Act by failing to quickly reduce impacts of lobster fishing gear on the North Atlantic right whale.” (The Guardian, 8 Sept 2022).

Seafood Watch’s lobster red list may prompt swift action as a shrimp red list did in 2015 for the Louisiana shrimp fishery.

I hope the impasse ends soon, though it doesn’t affect me personally. My husband is a Fish Frowner — no “fishy” smells at home — so I’ve rarely eaten seafood for 40+ years and, given the choice, I prefer shrimp to lobster. So glad the shrimp red list got solved.

(photos from Wikimedia Commons and via Flickr Creative Commons licensing; click on the captions to see the originals)

This! is Shorebird Migration

Semi-palmated sandpiper flock (photo from Wikimedia Commons)

19 August 2022

Check out this swirling flock of semi-palmated sandpipers on migration this week.

Is there a merlin out there?

(photo from Wikimedia Commons; click on the caption to see the original)

All The Avocets

Pied avocet (photo from Wikimedia Commons)

13 August 2022

Around the world there are four species of avocets, genus Recurvirostra.

The pied avocet (Recurvirostra avosetta), above, is native to half of Africa, central Asia to China, and parts of India and Southeast Asia.

The red-necked avocet (Recurvirostra novaehollandiae), below, is native to Australia.

Red-necked avocet, Australia (photo from Wikimedia Commons)

The Andean avocet (Recurvirostra andina) is native to the Andes of South America.

And the American avocet (Recurvirostra americana) is native to North America, shown below in breeding and non-breeding plumage.

American avocet in April (photo from Wikimedia Commons)
American avocets in December (photo from Wikimedia Commons)

Though they look a lot alike, none of them share a continent.

(photos from Wikimedia Commons; click on the captions to see the originals)

Red Knot Family Life

Red knot on northward migration in Sanibel, Florida (photo from Wikimedia Commons)

12 August 2022

Red knots (Calidris canutus) stop in the Lower 48 States on migration and for the winter.

Range map of red knot subspecies (map from Wikimedia Commons)

But they nest in the Arctic so we never see them raise their chicks.

Here’s a quick look at red knot family life.

Notice that there are bands on several of the birds. Red knots are often banded and studied because they are Near Threatened.

By the way, you may have seen a red knot in fall or winter but not recognized it. At that time of year they are not red!

Red knots in Ohio in September (photo from Wikimedia Commons)

(photos and map from Wikimedia Commons; click on the captions to see the originals)