Category Archives: Water and Shore

Mallards As Carnivores

Water and Shore
Female mallard (photo from Wikimedia Commons)

9 March 2022

We think of mallards (Anas platyrhynchos) as dabbling ducks that eat plant material and bread tossed by humans(*) but these common ducks are actually omnivorous and opportunistic. Their diet depends on time of year.

On migration and in winter mallards are basically vegetarian, eating seeds, acorns, aquatic vegetation, cereal crops, and in urban areas human-provided bread and birdseed.

Mallard pair looking into water (photo from Wikimedia Commons)

During the breeding season mallards add meat to their diet including gastropods (snails), insects, crustaceans (such as crayfish) and worms.

Mallard eating leopard frog (photo from Wikimedia Commons)

They’ve been known to eat frogs (see above) and in one surprising episode in 2017 a flock of mallards in Romania were observed hunting small migratory birds including grey wagtails and black redstarts.

Fortunately small bird consumption is quite unusual and unnecessary. Males and non-laying females eat only 37% animal matter in the breeding season while laying females consume 71.9% animal matter to meet their energy needs.

I saw a pair of mallards mating at Panther Hollow Lake last weekend so I know the breeding season has begun in Pittsburgh. Laying females will be bulking up on snails, insects and worms.

Meanwhile most mallards are still on migration to their breeding grounds. They will change their diet soon.

Mallard range map (image from Wikimedia Commons)

(*) p.s. Mallards eat bread but it has very poor nutrition and is actually bad for them. See Bread is Bad for Birds.

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

Snowy Egret’s Fishing Feet

Bird Behavior, Water and Shore
Snowy egret in Celebration, Florida (photo from Wikimedia Commons)

7 March 2022

How do you identify a snowy egret among the six white wading birds in North America?

Snowy egrets are the only one of the group whose feet don’t match their legs. Yellow Feet + Black Legs. You can see it even in flight.

Snowy egrets in flight (photo from Wikimedia Commons)

The color combination helps them forage. While their black legs are probably ignored by their prey, the “yellow feet catch the eye of fish and other creatures, drawing them closer or stalling them so the egret can strike,” per Bird Watcher’s Digest.

Here are three of the snowy egret’s five foot-fishing techniques.

Foot stirring:

Foot probing: in slow motion.

Foot dragging: Dangling their feet in the water to make the fish rise up from the depths.

Snowy egrets have 21 techniques for catching fish, the broadest repertoire of all North American herons. They have a lot of tricks up their sleeves.

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

Today’s Flood is Tomorrow’s High Tide

Climate Change, Water and Shore
High tide in Miami, 16 Oct 2016 (photo from Wikimedia Commons)

27 February 2022

Much of the coastal U.S. floods during violent ocean storms but some places, like Miami, flood several times a year during high “spring” or “king” tides because of climate-driven sea level rise. This month a new report from NASA and NOAA recalculates how deep the water will be just 30 years from now. It doesn’t look good.

By 2050, the average rise will be 4 to 8 inches along the Pacific, 10 to 14 inches along the Atlantic, and 14 to 18 inches along the Gulf.

— WIRED Magazine: Sea Level Rise Will Be Catastrophic—and Unequal

As Wired Magazine points out, these amounts are averages because water basin topography, water temperature (warmer water takes up more space), land subsidence, and glacial rebound make unique results for each location.

Comparing just two cities on different coasts neatly illustrates what a striking difference these factors can make. Galveston, Texas, where the land is slumping, could see almost 2 feet of rise by the year 2050. Meanwhile, Anchorage, Alaska, could see 8 inches of sea level drop, thanks to the fact that its land is actually rising following the departure of long-gone glaciers.

— WIRED Magazine: Sea Level Rise Will Be Catastrophic—and Unequal

The report indicates that a 2-foot rise is already locked in for 2100 because of past greenhouse gas emissions. If we don’t stop emitting *now* we can expect an additional 1.5 to 5 feet for a total of 3.5 to 7 feet by the end of this century.

NOAA’s Sea Level Rise Viewer shows Galveston, Texas, below, in three scenarios: current sea level, +2 feet (expected by 2050) and +7 feet (in 2100 if nothing changes). In 30 years Bayou Vista, Tiki Island and Jamaica Beach will be gone. A 7-foot rise by 2100 wipes out most of the area.

  • Galveston, Texas at current sea level (map from NOAA Sea Level Rise Viewer)

No matter what happens the results will be unequal. Southern Alaska (blue dots) looks good under both scenarios. The Gulf and Atlantic coasts will be in various degrees of trouble.

The report is sobering because it’s unfolding so soon. If you’re 30 years old now, some Gulf Coast places will be gone by the time you’re 60.

Road Ends in Water (photo by eagle102 on Flickr via Creative Commons license)

Today’s catastrophic flood will be tomorrow’s high tide.

Curious about your favorite coastal places? Look them up on NOAA’s Sea Level Rise Map Viewer.

(images from Wikimedia Commons, NOAA’s Sea Level Rise Viewer and NASA & NOAA’s 2022 Sea Level Rise Technical Report; click on the captions to see the originals)

Scenes from Duck Hollow

Water and Shore
A flock of gulls takes off as a towboat passes, Duck Hollow, 17 Feb 2022 (photo by Jim McCollum)

26 February 2022

Despite Pittsburgh’s overcast skies, winter can be beautiful along the Monongahela River. Jim McCollum often stops by Duck Hollow to capture its many moods.

Ring-billed gulls visit Pittsburgh in winter and on migration to their nesting grounds at the Great Lakes and Canada. In February adult ring-bills look sharp in breeding plumage.

Ring-billed gull on a log tossed up by the river, Duck Hollow, 18 Feb 2022 (photo by Jim McCollum)

This month Pittsburgh had more than 5 inches of rain with several big rain events: 1.02″ on 3 Feb, 1.60″ on 17 Feb, and 1.07″ on the night of 24-25 Feb. When the flood waters receded on 24 Feb they left behind an unusable gift on the remnant mud bank which had never had a picnic table. Soon the water rose again.

A “gift” from the river is deposited on the mud bank, Duck Hollow, 24 Feb 2022 (photo by Jim McCollum)

In addition to gulls Duck Hollow has visiting ducks in winter, including common mergansers (Mergus merganser).

Common mergansers at Duck Hollow, 31 Dec 2021 (photo by Jim McCollum)

And there are always mallards (Anas platyrhynchos) that give the place its name.

Male mallard lands on still water at Duck Hollow, 30 Dec 2021 (photo by Jim McCollum)

p.s. Duck Hollow is at the end of Old Browns Hill Road and across the river from Homestead, near the Homestead Gray’s Bridge (previously called the Homestead High Level Bridge). Click on this link to see it on the map.

(photos by Jim McCollum)

Watch Wading Birds

Quiz, Travel, Water and Shore
Wading birds feeding in Florida (screenshot from MyBarckyardBirding on YouTube)

24 February 2022

Take a visual trip to Florida and watch at least 10 species of birds feeding in a marsh. Notice that some stab at underwater prey, others nibble below the surface, some pick at the shore and some (the pink ones!) swipe their bills side-to-side.

How many of them can you identify? Leave a comment with your answer.

(Note: The embedded video from @MyBackyardBirding is limited it to the first two minutes. Click here to see the entire 13.5 minute video.)

Check back later for my checklist from the video.

(screenshot and embedded video from MyBackyardBirding on YouTube)

LATER. Here’s my list of the birds I saw in the video:

  1. Great egret
  2. Snowy egret
  3. Little blue heron
  4. Tricolor heron
  5. Glossy ibis
  6. White ibis
  7. Roseate spoonbill
  8. Boat-tailed grackle
  9. Lesser yellowlegs
  10. Greater yellowlegs.

From Midway to Mexico

Travel, Water and Shore
Black-footed albatross (photo from Wikimedia Commons)

18 February 2022, San Diego Bird Festival, Pelagic Tour

For most of their lives black-footed albatrosses (Phoebastria nigripes) wander the North Pacific visiting land only to nest.  When they do 97.5% of them breed on the Northwestern Hawaiian Islands, the green swath at the center of the Birds of the World map embedded below.

Breeding and dispersal range of black-footed albatross (map embedded from Cornell Lab Birds of the World)

Of that 97.5%, one third nests on Midway Atoll, especially on Eastern Island which hosts the largest albatross colony in the world.

Map of Midway Atoll from Wikimedia Commons

Unfortunately Eastern Island averages only 2.6 meters above sea level. This puts the albatross nests in grave danger. In 2011 a tsunami wiped out 30,000 nests and …

A 2015 study estimated that a 2-meter sea level rise and storm waves—possible in the next century under many climate change scenarios—would flood up to 91% of black-footed albatross nests on the Eastern Island of Midway Atoll.

— Science Magazine: ‘They were destined to drown’: How scientists found these seabirds a new island home

Since black-footed albatrosses don’t reproduce until they are seven years old and then raise only one chick every two years the species will quickly go extinct if they don’t have a safe place to nest, so scientists developed a plan to establish a colony at Guadalupe Island, Mexico, a biosphere reserve off the west coast of Baja California that rises as high as 1,298 meters above sea level.

Location of Guadalupe Island, Mexico, embedded from Google Maps

This Science Magazine video shows how black-footed albatross chicks and eggs were translocated more than 3,500 miles to protect them from future extinction.

Today I’m on a pelagic tour off the coast of California where I hope to see the black-footed albatross, though they are rare at this time of year in the locations we are visiting. Even if we do see one, it is extremely unlikely that it came from Guadalupe Island.

To give you an idea of what a pelagic tour is like, here’s a video from a tour out of San Mateo County, California. Everyone’s focused on the northern fulmar and mention the black-footed albatross as a reference point. A reference point! It would be a Life Bird for me.

Video by Colette Micallef on Shearwater Journeys out of San Mateo County, CA.

UPDATE 21 Feb 2022: As expected, I did not see a black-footed albatross.

(photo from Wikimedia Commons, range map embedded from Birds of the World; click on the cpations to see the originals)

European Ancestry?

Musings & News, Water and Shore
Mallards in Durham, NC (photo from Wikimedia Commons)

31 January 2022

Mallards have always been abundant in western North America so I was surprised to learn that until the 20th century they were rare east of the Mississippi. Here’s how that changed:

Mallards were once rarely encountered throughout much of the Atlantic Flyway. That began to change during the 20th century, as the expansion of agriculture in eastern Canada opened the Boreal forest, creating ideal habitat for pioneering mallards from the west. To the south, in the eastern United States, government agencies and private citizens worked for decades to establish a huntable mallard population through the large-scale release of game-farm birds. Mallard numbers grew exponentially in the east, and by the 1960s, mallards had become the most abundant duck in the Atlantic Flyway.

— ducks.org: The Surprising Genetics of American Black Ducks and Mallards

As the mallard (Anas platyrhynchos) population increased in the East, American black ducks (Anas rubripes) decreased and the two species hybridized. A hybrid is shown below.

Hybrid mallard x American black duck (photo by Dan Mullen via Flickr Creative Commons license)

Questions about hybridization prompted genetic testing. The results were surprising for mallards.

Wild mallards in the eastern U.S. all have game-bird ancestors introduced from Europe. The further east you go, the more European ancestry they have. Mallards in the western U.S., such as this pair in California, have pure western genes.

Mallards in Redwood City, California (photo from Wikimedia Commons)

Eastern mallards of game-farm stock are slightly different than native wild mallards, though it probably takes an expert to tell the difference. According to The Surprising Genetics of American Black Ducks and Mallards (paraphrased below):

  • “Mallards with game-farm ancestry average 10 – 14 ounces less than the wild birds.
  • Their bills have structural differences likely derived from a diet of domestic grains.
  • Males are overly aggressive.
  • Females have a prolonged breeding period, produce excessive numbers of eggs, and show poor nest vigilance.”

The real danger, if there is one, is that native mallards west of the Appalachians are becoming diluted by interbreeding with game-farm descendants. But maybe this doesn’t matter.

What about black ducks? For them the news is happy. Genetic testing showed that pure American black ducks don’t breed with the hybrids so their genes are clear. Instead the hybrid mallard x black ducks breed with mallards.

p.s. Tip of the Hat to Stephen Tirone for alerting me to this interesting article.

(photos from Wikimedia Commons and by Dan Mullen via Flickr Creative Commons license; click on the captions to see the originals)

Mallards Help Plants in Winter

Bird Behavior, Plants & Fungi, Water and Shore
Flock of mallards in Järvenpää, Finland (photo from Wikimedia Commons)

26 January 2022

Since plants are rooted to the ground, the only way they find a new place to live is through seed dispersal. Pressure to find new places is intensified by climate change but a study published this month in Science points out:

Half of all plant species rely on animals to scatter their seeds through hitchhiking in scat, fur, or beaks. When mammal and bird populations decline, so does the ability plants have to disperse their seeds and adapt to climate change. Loss of mammals and birds cuts a plant’s ability to adapt by 60 percent.

— With Fewer Animals to Move their Seeds, plants are stuck in threatened habitats

Mallards to the rescue.

In 2017 study at Utrecht University found that mallards (Anas platyrhynchos) significantly help plants and isolated wetlands by dispersing seeds in winter.

Mallards change their diet during the year, from carnivorous in the breeding season to vegetarian in winter. During migration they stop to eat then disperse seeds later along the way. This particularly helps isolated wetlands that would not gain new seeds otherwise.

Mallards also help every day on their wintering grounds by moving back and forth from roosting to feeding areas. Where there is hunting pressure you might not see this because mallards change their ways: eating at night and hiding at the roost during the day.

Mallards in flight (photo by Imran Shah via Wikimedia Commons)

Mallards are the most abundant duck species on earth and perform this seed dispersal service on four continents: North America, Europe, Asia and Africa.

Find out more at Wintering Ducks Connect Isolated Wetlands by Dispersing Plant Seeds.

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

They Never Get Old

Fish, Frogs, Musings & News, Water and Shore
Juvenile European lobster (photo from Wikimedia Commons)

16 December 2021

Stress makes humans age faster so it’s no wonder that pandemic stress has made many of us feel and even look older.

Unlike us, however, lobsters are biologically immortal. They don’t slow down, they don’t get frail, they don’t die of old age. Lobsters never get old.

Their lack of aging is described in this vintage article from 2014, written at a time that was stressful for my family but turned out happy in the end.

Biological Immortality

(photo from Wikimedia Commons of a juvenile European lobster, closely related to the American lobster)

Why Aren’t The Ducks Here Yet?

Climate Change, Migration, Water and Shore
Mixed ducks in flight, San Luis National Wildlife Refuge, Jan 2008 (photo from Wikimedia Commons)

8 December 2021

Fifteen years ago Pittsburgh birders waited for migrating waterfowl to start arriving in late October and watched as numbers peaked in November and dropped when our lakes froze in December. We remember that schedule and have been visiting wetlands since late October but waterfowl are still scarce. Low variety, low numbers.

Why aren’t the ducks here yet?

In a word, it’s not cold enough.

Except for the few species that are hardwired for more dependable long-distance migrations, such as blue-winged teal, waterfowl are adapted to migrate only as far as is necessary for them to find food, open water, and places to rest. For some species, it may take several consecutive days of freezing temperatures and snow cover to push them southward. 

— Ducks Unlimited: Are Waterfowl Migrations Changing?

Ducks save energy and avoid danger by staying put when conditions allow. They also shortcut their trip north in the spring by not traveling too far from their breeding grounds.

There was no reason for ducks to fly south in October, which was the world’s fourth warmest on record. November was also warm with no highs below freezing in Erie, PA and only four days completely below freezing in typically cold Bismarck, North Dakota. As of Monday December 6 the Great Lakes were completely ice free.

NOAA CoastWatch Great Lakes Ice Analysis. NO ICE as of 6 Dec 2021

So we’ll just have to wait for a week of real winter before we’ll see good flocks of migrating ducks.

Follow the weather up north to get a prediction of waterfowl arrival. Did it freeze in Saskatchewan, Manitoba or Ontario? Did the Great Lakes start to freeze? What about Lake Erie? (click the link to see Great Lakes ice conditions.)

When the ducks get here they might not leave until spring if our lakes stay open.

Mixed ducks in Ohio, March 2014 (photo from Wikimedia Commons)

p.s. Yesterday’s high was below freezing but we’re not having a run of cold weather. Friday’s high will be 52oF, Saturday’s 64oF.

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