Category Archives: Water and Shore

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.

Two Puffins And A Unicorn

Tufted puffin in Alaska (photo from Wikimedia Commons)

Alaska Birding with PIB: Pelagic tour at Kenai Fjords National Park 19 June 2019

Last summer I went to Newfoundland to see the only puffin we ever think about in eastern North America, the Atlantic puffin (Fratercula arctica). In the Pacific there are two more puffins and a closely related bird that’s like a unicorn. Today I hope to see all three.

Atlantic or Pacific, the first thing to know about puffins is that all of them are pelagic. They spend most of their lives far out at sea and only come to land in the breeding season when they look their very best. If you want to see a puffin you have to visit their homes in early summer. Otherwise they’re gone.

The tufted puffin (Fratercula cirrhata) is the largest of them, more powerful than cute. Almost double the weight of the Atlantic puffin, his breeding plumage includes a bright orange beak, white face, and long golden head plumes. His extensive breeding range makes him relatively easy to find on coasts and islands from California to Japan. At their breeding colonies each pair digs a burrow up to five feet deep where they raise a single chick per year.

The horned puffin (Fratercula corniculata), below, resembles the Atlantic puffin but he’s 40% larger, has a mostly yellow beak, and feather “eyebrows” like horns. There’s no danger you’ll mix them up in the wild. The horned puffin is only in the Pacific, the Atlantic puffin is only in the Atlantic.

Horned puffin (photo from Wikimedia Commons)

The horned puffin also differs in his nesting strategy. These pairs don’t burrow to make a nest. Instead the female lays her single egg on scree in a rock crevice or on a cliff. Horned puffin breeding colonies range from (rarely) British Columbia to Alaska to the Sea of Okhotsk (Russia and Japan).

And finally there’s the unicorn.

The rhinoceros auklet (Cerorhinca monocerata) is not an auklet at all but the closest relative of puffins. Slightly larger than an Atlantic puffin he has a large orange bill with a single horn protruding from it, leading some to call him the unicorn puffin.

Rhinoceros auklet (photo from Wikimedia Commons)

The rhinoceros auklet nests on offshore islands from California to the Gulf of Alaska to Korea and Japan. You’ll see them on the water during the day but not on land. Instead they fly home at night with fish to feed their chicks. As they arrive at the nesting colonies they run the gauntlet of gulls waiting to steal their food (see video below). Perhaps that’s why they come home only at night.

The unicorn has a different lifestyle but he’s a puffin nonetheless.

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

Arctic Terns Have Short Legs

Arctic tern (photo from Wikimedia Commons)

Alaska Birding with PIB: Birding Anchorage to Denali 14 June 2019

The first time I saw an Arctic tern was on a bird outing at Cape May, New Jersey in May 2004. It was the only Arctic tern perched in a big flock of common terns. How to pick it out of the crowd? “Look for the tern with the short legs.”

Arctic, common and Forster’s terns are in the same genus so it’s a challenge to identify them, especially since we don’t get any practice with Arctic terns in Pittsburgh.

In Alaska, terns are simpler. There are only four species: Common tern is very rare. Caspian tern is the only one with a big carrot-red bill. Arctic terns are everywhere and Aleutian terns look different.

Famous for their long distance Arctic to Antarctic migration, Arctic terns (Sterna paradisaea) are pale gray and white with uniformly silver gray upper wings, small round heads, short dark red bills, and short red legs. In the breeding season they have very long white tail streamers.

Arctic tern in flight (photo from Wikimedia Commons)

When they’re breeding Arctic terns are quite vocal. If you get too close to a nest they shout and dive bomb you. How close is too close? On the tundra where they nest alone, you may not know there’s a nest until you’re under attack.

Arctic tern in flight (photo from Wikimedia Commons)

Aleutian terns (Onychoprion aleuticus) are uncommon and local but easy to identify because they’re dark gray with white tails, white foreheads, black legs, black bills, and white edging on their wings. There’s no mistaking who they are when they’re standing.

Aleutian terns pair (photo from Wikimedia Commons)

You can see the Aleutians’ white foreheads in flight.

Aleutian tern in flight (photo from Wikimedia Commons)

Even though it’s not a useful field mark in Alaska, Arctic terns are still the ones with the short legs.

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

Make Way For Ducklings

On the morning after her eggs hatch, the mother mallard leads her ducklings to water where they’ll be safe. Unfortunately in the city there are unexpected hazards on the way.

Sometimes she walks over grates that are too open for her ducklings and they all fall in. In Phoenix, Arizona the Fire Department rescues ducklings at least once a year.

When her family is reunited Mother Mallard leads them away.

Mother mallard leads her ducklings after rescue, 1 July 2006 (photo by Starbuck Powersurge on Flickr, Creative Commons license)

p.s. Notice that she’s fanning her tail to show white feathers. Perhaps her ducklings cue on that signal.

(video by Woodside Homes Arizona on YouTube. photo by Starbuck Powersurge on Flickr, Creative Commons license

When Puffins Become Photographers

Happy news for a Happy Friday.

This amazing video posted on Twitter by @bryony6912 was filmed at Skokholm Island UK, Britain’s first bird observatory and the densest Manx shearwater colony on Earth. There are lots of other seabirds there including Atlantic puffins.

When puffins become photographers. 🙂

Mallard Moms Are On The Nest

Only two weeks ago the mallard flock at Duck Hollow was large and busy with males and females feeding in pairs. Back then the flock was usually 20+ birds but now it’s half that size and mostly male. The females are missing. They’re on the nest.

Female mallards (Anas platyrhynchos) nest on the ground laying one egg per day until the clutch is complete, about 10 eggs.

Though she doesn’t build the nest the mother mallard pulls nearby vegetation toward her body to line the nest bowl. When she begins incubation she plucks down from her breast to surround the eggs and cover them while she’s gone. The eggs hatch in 28 days.

Only the females incubate eggs while the males watch from afar. Except for a recess in early morning and late afternoon, female mallards are hidden all day — if they’ve chosen a good nest site.

In urban settings the ladies choose some creative places, as in the video above and this photo under a stairway in Madison, Wisconsin.

Mallard nesting under a stairway in Madison, Wisconsin (photo from Wikimedia Commons)

Three days before they hatch the mallard chicks call back and forth with their mother from inside the eggs. On hatch day all of them emerge within 6-10 hours. Next morning their mother leads them to water for their first swim. See all of this in Ian Oland’s video, above.

So don’t be surprised when you don’t see female mallards at Duck Hollow in early April. Right now the mother mallards are on the nest.

(video by Ian Oland on YouTube. photo from Wikimedia Commons; click on the caption to see the original)

Golden Camouflage

European golden plover in Iceland (photo from Wikimedia Commons)

The world’s three species of golden plovers — European (Pluvialis apricaria), American (P. dominica) and Pacific (P. fulva) — are so stunning in golden breeding plumage that they stand out when we look at them. How do these ground-nesting birds avoid predation when they look so obvious?

They’re wearing golden camouflage.

Above, a European golden plover is easy to see from the side, but blends into the background in the photo below, matching the tundra.

European golden plover blends into the background (photo from Wikimedia Commons)

Speckled golden plumage hides them while they’re incubating. (American golden plover below)

American golden plover matches the ground (photo from Wikimedia Commons)

And their chicks are perfectly camouflaged to match the tundra habitat. Can you find the chick in the photo below?

Who knew that gold can look like moss?

(photos from Wikimedia Commons; click on the captions to see the originals. Embedded tweet from @CrowsAndCompany)