Category Archives: Water and Shore

What Swans Do With Their Heads Underwater

This week Britain’s BBO Wildlife Trust shared a glimpse into the underwater world of swans and ducks.

Mute swans have such long necks that they can feed on the bottom while floating on the surface. Ducks have to dive.

While the swan is feeding tufted ducks come and go, their bodies so buoyant that their feet must flap continuously to keep them submerged.

If this had been filmed in North America they would be our own species: tundra swans and ring-necked ducks.

(video from Jack Perks via BBO Wildlife Trust)

Courting Cahows

Pair of Bermuda petrels at Nonsuch Island, Bermuda, 31 Oct 2019 (screenshot from Cornell Labs Bermuda Cahowcam)

November is courtship time for one of the rarest seabirds on earth.

The Bermuda petrel (Pterodroma cahow) or cahow (pronounced ka-HOW) ranges across the Atlantic Ocean, returning to land only once a year to court and breed at Bermuda.

Cahows nest in dark burrows which they access only at night, so secretive that they were presumed extinct until 1951 when the last 17-18 pairs were discovered on an isolated Bermuda island.

Every year the odds are against an egg becoming an adult. However the birds’ long breeding lives, 30-40 years, ensure the species will survive as long as there are safe places to nest — and that’s the rub. Rats were eradicated from their breeding colonies but many of the burrows are on islands threatened by hurricanes and sea level rise.

Since 2001 the Cahow Recovery Program has been setting up safe breeding burrows on Nonsuch Island and translocating a few pre-fledgled birds to the burrows in hopes they will return there to breed when they reach maturity at 3-6 years of age. So far so good. There are now 15 pairs on Nonsuch, two of which use burrows equipped with live streaming Cahow cams under infrared light.

November is the time to watch the cameras at Cornell Lab’s Bermuda Petrel Cams. The pairs return to their burrows, prepare the nest, court and copulate. In the video below a pair touches beaks and preens in the courtship behavior called allopreening.

Watch the Cahow cams this month, especially at night. The birds are most active on the darkest nights of the New Moon.

Cahows leave their burrows in December, then the female returns in January to lay her single egg. If all goes well a chick will fledge in July.

The long process of creating and raising a single cahow chick has just begun.

p.s. Here’s an amazing fact about cahows: Notice that the birds have tube-like noses. These structures take the salt out of saltwater so they can drink it. They sneeze the salt out of their noses. There are more amazing cahow facts here.

(screenshot and video from Cornell Lab’s Bermuda Petrel cams)

My Name Is Halloween

Halloween hermit crab (photo from Wikimedia Commons)

Yesterday’s peregrine news pre-empted this Halloween post, so here it is a day late.

The Halloween hermit crab (Ciliopagurus strigatus) lives in cone-shaped shells on coral, rubble, and rocky reefs in the Indian and Pacific Oceans. Just two inches long, he forages at night on meat, carrion, seaweed and algae. His scavenging behavior makes him a useful cleaner-upper in reef aquariums.

However, watch out! The Halloween hermit crab is belligerent. He will …

  • Fight other hermit crabs for a desirable shell.
  • Steal an occupied shell by yanking a weaker hermit crab out of it. (This means death for the homeless crab.)
  • Trample and ruin flat corals,
  • Steal food from the mouths of large corals,
  • Eat docile bottom-dwelling fish in the aquarium.

If this crab is not fed meat, he eats his neighbors.

Not a compliant pet. Scary!

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

Hermit Crabs Get Creative

This video tweeted by @StrangeAnimaIs shows a hermit crab using an abandoned doll’s head as a shell. Why would a crab do this?

In some parts of the world there’s such an acute shortage of shells that hermit crabs use trash instead. This BBC video shows them on a beach in Thailand. Click here to see a crab in a can in Malaysia.

Seashells are missing because people and poachers collect them.

Animals that get creative are the ones who survive. Welcome to the Anthropocene.

Is The Blob Back Again?

Sea surface temperature anomalies in northeast Pacific, 2014 and 2019 (maps from NOAA)

In the fall of 2014 a persistent weather pattern in the northeastern Pacific stopped the normal upwelling of cold water from Alaska to California. Sea surface temperatures rose 7 degrees F.

When that happened, cold water nutrients and organisms stayed too far below the surface to feed the fish, birds and animals that depend on them. Species starved throughout the food chain including crabs, sea stars, salmon, Cassin’s auklets, common murres, and sea lion pups.

Cassin’s auklet takes off (photo from Wikimedia Commons)

This month a similar weather pattern has created a similar temperature anomaly. NOAA says it already ranks as the second largest marine heatwave in the northern Pacific Ocean in 40 years — second only to “the Blob.” (see maps above)

If the weather doesn’t change soon, if the winds don’t pick up and stir the sea, then “The Blob” will be back again and it will be bad news for everything in the northeastern Pacific.

Learn what happened during The Blob of 2014-2015 in this vintage article: Death By Warm Water.

(maps from NOAA, photo from Wikimedia Commons; click on the captions to see the originals)

Turtles Ride Out The Storm

Loggerhead sea turtle off Sandy Point, Abaco, 2006 (photo from Wikimedia Commons)

Loggerhead sea turtles (Caretta caretta) live underwater but must surface to breathe and walk up the beach to lay their eggs. They’re vulnerable to extinction due to loss of nesting habitat, fishing bycatch and vessel strikes. Scientists also wondered: Do tropical storms pose risks for adult sea turtles?

In June 2012 just before Tropical Storm Debby began to spin off of Florida’s Gulf coast, scientists tagged a loggerhead sea turtle with a GPS tracking device. Nicknamed Eleanor, she laid eggs on the beach and returned to the sea near Sarasota. Then the storm arrived.

Would the storm hurt Eleanor? They watched her for clues.

Tagged loggerhead sea turtle returning to the sea after laying eggs, Archie Carr NWR, Florida (photo from Wikimedia Commons)

Before the storm Eleanor saved energy for her next egg-laying excursion by resting on the seabed and only moving when she surfaced for air.

When Tropical Storm Debby arrived, Eleanor was caught in it and swept north by its current. The storm churned for four days with sustained wind speeds of 65 mph. Eleanor was active the entire time.

Tropical Storm Debby, 24 June 2012 (photo from Wikimedia Commons)

Instead of resting she swam, dove, and surfaced. Amazingly, this used no more energy than she would have expended on producing 2% of her next set of eggs. Meanwhile the storm pushed her 62 miles (100 km) north of her nesting beach.

Loggerhead sea turtle (photo from Wikimedia Commons, Creative Commons license)

When the storm was over, Eleanor swam south, found her nesting beach, and laid her next clutch just 250 feet (75 m) from her last one.

Sea turtle tracks after egg laying (photo from Wikimedia Commons)

The study concluded that tropical storms don’t pose much risk to adult sea turtles like Eleanor.

Unfortunately, as researcher Maria Wilson pointed out, “Sea turtle nests are extremely vulnerable to passing storms. The storm that Eleanor easily survived destroyed almost 90% of nests on the beach where she and several hundred other female turtles had laid their eggs.”

The study concluded that when it comes to protecting seas turtles we should focus on protecting nests and helping newly hatched turtles. We don’t need to worry about the adults. They can ride out the storms.

Read more in this article at Science Daily. Note: These are not photos of Eleanor.

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

Watch Out, Miami!

Screenshot from Modeling the Greenland Ice Sheet by NASA Goddard

This summer’s arctic heat wave caused rapid melting of the Greenland ice sheet and raised fears that it may disappear in 1,000 years. If it does, our models for future sea level rise are way too low.

That news was eclipsed this week by Hurricane Dorian’s devastation of the Bahamas and threats to the East Coast. The Carolinas took a beating but Miami, pictured below during Hurricane Irma, was spared.

Hurricane Irma in Miami Beach, 10 Sept 2017 (photo from Wikimedia Commons)

Interestingly, Miami has more to worry about from Greenland than from any hurricane.

On 1 August 2019 CNBC wrote, “The historic heatwave that scorched Europe last week has moved to Greenland, where it’s expected on Thursday to melt away 12 billion tons of water from the ice sheet and irreversibly raise sea levels across the world. … This week’s melt alone is estimated to permanently raise global sea levels by 0.1 millimeters.”

A measurable sea level rise in only one week?! NASA Goddard modeled the future of the Greenland ice sheet in the video below. If all of it melts, the sea will rise 80% more than we expected.

Miami should be especially worried about Greenland. Not only will it add a lot of water to the ocean but it’s location will force the water to rise even more in Miami due to uneven gravitational forces around the globe. Learn more about the relationship between location and sea level rise at Which Glaciers Will Flood Your City?

Map of glacial contribution to sea level rise in Miami (screenshot from NASA JPL)
Map of glacial contribution to sea level rise in Miami (screenshot from NASA JPL)

Watch out, Miami! Greenland is going to make a splash.

(Greenland screenshot and video from NASA Goddard, photo of Miami Beach during Hurricane Irma from Wikimedia Commons, screenshot of glacial contribution to sea level rise from NASA JPL)

In The Doldrums

The doldrums appear as a band of clouds near the thermal equator (satellite image from Wikimedia Commons)

When we say we’re “in the doldrums” we feel depressed, dull and listless. Those with Seasonal Affective Disorder (SAD) — a type of depression related to the change of seasons — may be in the doldrums already though it’s only late August. They’re aware that Pittsburgh has lost an hour and 48 minutes of daylight since the June 21 solstice.

The real doldrums, whose fancy name is the Intertropical Convergence Zone (ITCZ), is dull and listless too. The ITCZ or “itch” is a band of monotonous calm where the north and south trade winds converge. As the winds meet each other they travel straight up, causing windlessness on the surface and clouds above. The calm is a real hazard for sailors who depend on wind to power their ships.

The lack of wind doesn’t mean the weather is beautiful. Rising heat and moisture lead to stacks of clouds, frequent thunderstorms and heavy rainfall. Some of the storms spin away from the doldrums as tropical depressions that become hurricanes.

You can see the ITCZ from satellite as a band of clouds near the thermal equator (photo at top). At this time of year there may be a dense circle in the line of clouds, a newly forming tropical depression.

The ITCZ moves north in the summer especially over land (which is warmer) and south in the winter, causing rainy and dry seasons in the tropics. The map below shows where the ITCZ usually goes; its path in the Pacific is affected by El Nino.

Seasonal variation of the ITCZ or doldrums (map from Wikimedia Commons)

Though the doldrums are deadly calm they can generate too much excitement (storms). Read more about them from the sailor’s point of view at: Seven things you need to know about the Doldrums.

(images from Wikimedia Commons; click on the captions to see the original)

Unusual Visitor In Duquesne

Yellow-crowned night-heron in Duquesne, PA (photo by Oliver Lindheim)

In August 2019 a rare bird showed up every evening at an industrial park in Duquesne, PA. The bird was outside his normal range, but this is not surprising for a juvenile yellow-crowned night-heron.

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

Related to egrets and bitterns, yellow-crowned night-herons (Nyctanassa violacea) live near water and eat mostly crustaceans. Some live year round in Central and South America. Others breed in North America and migrate south for the winter as shown on the map below.

Range map of yellow-crowned night-heron, yellow is breeding range (map from Wikimedia Commons)

However, juvenile yellow-crowned night-herons are great wanderers. As Cornell Lab’s All About Birds explains, “After the breeding season, young birds often disperse to the north or west before heading to wintering grounds.” That’s how they end up in Newfoundland, North Dakota and Duquesne, PA.

At 4pm on Sunday August 18, I went to see him at the industrial park but he wasn’t there because (duh!) he’s a night-heron. So I went back at 7:20pm.

He attracted a small crowd. Five of us watched him roam the sidewalks and grass beneath the pine trees at American Textile Company. He was so unafraid of humans that he walked right past two people standing on the sidewalk. This bird is completely focused on cicadas.

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

To give you an idea how close he came, here are photos from Oliver Lindheim (at top) and Amy Henrici, two of the many birders who’ve made the trek to Duquesne.

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

As soon as the glut of cicadas is over, this bird will be on his way.

UPDATE 26 August 2019: This bird is gone. He didn’t show up on the evening of August 21.

NOTE: If you went to see the yellow-crowned night-heron and you use eBird, please mark his location as the new “Stakeout” Hotspot created specially for him called “stakeout, yellow-crowned night-heron at City Center, Duquesne, PA.

(photos by Oliver Lindheim and Amy Henrici)