Category Archives: Water and Shore

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)

Move-In Day

Caribbean hermit crab hiding in his shell (photo from Wikimedia Commons)

If you’ve noticed a lot of traffic in the City of Pittsburgh and a few street closures in Oakland here’s why: This week is Move-In Day at every university in town — six of them.

Move-In Day is our annual human effort at something that hermit crabs do all the time. Because they outgrow their shells hermit crabs are frequently in the housing market. When lots of them need a new shell they get organized and all move-in at once. It’s called a synchronous vacancy chain and takes only a few minutes once it starts to roll.

Click the link to read more about Hermit Crab Move-In Day. It’s fascinating!

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

Spiny Tongues and Glowing Beaks

Puffin with a beakful of fish (photo by Steve Garvie, Creative Commons license on Flickr)

There are many cool things about Atlantic puffins (Fratercula arctica). Here are two things that might come as a surprise.

(1) When Atlantic puffins fly back to their nests to feed their hungry chicks they need to carry as many fish as possible. How do they clamp them in their beaks? They press their spiny tongues on the fish to hold them against the roof of the mouth.

(B) We think puffins’ beaks are beautiful but we’re seeing only half of it. Where we see yellowish stripes the puffins see glowing ultraviolet. Read more about their colorful beaks in this article from Audubon.org.

Atlantic Puffins engaged in (a) billing behaviour, which is associated with sexual signalling (Photo: T. Finch). We identified photoluminescence on the cere (arrow) and lamellae of Puffins found deceased in (b) UK and (c) Canada.

Atlantic Puffins engaged in (a) billing behavior; (b, c) photoluminescence of the bills in UV light (Photo: T. Finch from “Photoluminescence in the bill of the Atlantic Puffin Fratercula arctica,” scientific figure via ResearchGate).

(photo with fish by Steve Garvie, Creative Commons license on Flickr; puffins ‘billing’ in courtship and UV glowing beaks from Photoluminescence in the bill of the Atlantic Puffin Fratercula arctica via Researchgate)

From Hawaii to Alaska

Bristle-thighed curlew, Midway Christmas Bird Count, 2012 (photo by Bettina Arrigoni, Creative Commons license on Flickr)

Bristle-thighed curlews are so rare and hard to find that they’ve been called the birders’ Holy Grail. The word “Tahiti” in their scientific name, Numenius tahitiensis, tells us why. These birds are Pacific Islanders. Their remote breeding location in Alaska was not discovered until 1948.

Adult bristle-thighed curlews spend only two months on their breeding grounds at the central Seward Peninsula and Yukon Delta. They arrive in late May and begin nesting almost immediately.

Bristle-thighed curlew in Alaska, June 2016 (photo by Aaron Budgor, Creative Commons license on Flickr)

When the eggs hatch in June, the chicks are precocial and soon walk off the nest. At 3+ weeks old they learn to fly but they aren’t independent yet. At 5 weeks their parents leave them with a few caretaker adults and depart for the staging grounds at the Bering Sea.

Bristle-thighed curlew chick in Alaska, July 2014 (photo by T.Lee Tibbitts USGS via Wikimedia Commons)

There they fatten up for the first leg of their journey home — a non-stop 2,500 mile flight to Laysan, Midway Atoll in the Hawaiian islands. For some curlews the final destination is much further, as shown on the map below. (Red spots are breeding range, white arrow is first stop, blue circles are wintering locations.)

Bristle-thighed curlew range (base map from Wikimedia Commons)

Young curlews follow the adults a few weeks later. They won’t return to Alaska until they’re three to four years old.

This year I happened to visit Hawaii and Alaska on the same schedule as the bristle-thighed curlews. My Life Bird curlew was a fly-by at Kahuku Golf Course, Kauai on February 28, photographed here by Michael McNulty. Then I saw curlews again near Nome, Alaska in June.

Bristle-thighed curlew at Kauai, 28 Feb 2019 (photo by Michael McNulty)

Every year the curlews travel from Hawaii to Alaska. With a worldwide population of only 7,000 birds and sea level rise due to flood their home islands, this amazing bird is vulnerable to extinction.

p.s. Bristle-thighed curlews are closely related to whimbrels, whom they resemble. We saw and heard both species in western Alaska.

(photos by Bettina Arrigoni, Aaron Budgor, Michael McNulty and Wikimedia Commons; click on the captions to see the originals)

The Closest Family Ties

Transient killer whales near Unimak Island, eastern Aleutian Islands, Alaska

Flying home from Alaska, 24 June 2019

Before my trip to Alaska I rarely thought about killer whales because I’d never had a chance to see them. Now I have and they are quite impressive.

Killer whales or orcas (Orcinus orca) are the largest oceanic dolphin, occurring around the world. Some are resident, some transient, others live offshore. Offshore orcas travel the wide swaths of ocean shown on the map below.

Orca range map from Wikimedia Commons

Killer whales are apex predators but what they eat depends on their lifestyle. Resident whales eat fish and are very vocal because fish don’t run away when they hear an orca. Transient whales eat marine mammals, especially seals, and are silent because seals flee at the sound of a killer whale.

Like other dolphins, killer whales are very intelligent and highly social. They swim with their families their entire lives. The family groups are matrilineal, lead by the eldest mother and made up of her sons, daughters, grandchildren and even great-grandchildren. Her knowledge and traditions guide her family long after her reproductive years and actually insure that her children live longer than those whose mothers died.(*)

Resident killer whales of the Pacific Northwest are so well studied that scientists recognize them as individuals from their unique saddle patches behind their dorsal fins. Censuses indicate the population is in decline. The killer whales’ food source, chinook salmon, is also in decline. Are these whales starving? A NOAA Fisheries study in British Columbia used a drone to find out.

From the drone’s photos and videos, scientists could tell if an orca was thin and weak or plumb and strong. During the study they filmed two brothers swimming together, just as they had their entire lives. One was very thin and the two were vocalizing a lot as they swam south. Eventually the weak brother dove and was never seen again. His brother swam back alone, vocalizing on the way. It appears that he accompanied his dying brother during his last moments.

Watch this 11 minute NOAA video to learn more about the resident killer whale population in the eastern North Pacific. Read more about them at NOAA Fisheries.

Unmanned Aerial Vehicle Offers a New View of Killer Whales from NOAA Fisheries on Vimeo.

Killer whales have the closest family ties.

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

(*) Killer whales live into their 90s and are one of only three animals that go through menopause. Humans and pilot whales are the other two.