Category Archives: Musings & News

The Most Teeth in North America?

Sperm whale skeleton showing teeth (photo from Wikimedia Commons)

19 September 2022

Adult humans typically have 32 teeth after our wisdom teeth come in at age 12-14, but our count is low compared to other animals.

7-year-old smile with missing tooth (photo from Wikimedia Commons)

Which animal in North America has the most teeth?

The Virginia opossum (Didelphis virginiana) is a contender with 50 teeth in his small mouth. He shows them when he feels threatened.

Opossum showing teeth (photo from Wikimedia Commons)

Some say that sharks have the most teeth but as far as I can tell their tooth count, often lower than 100, is not as remarkable as their tooth replacement. For instance, young lemon sharks replace all their teeth every 7-8 days so that in their lifetimes “the lemon shark Negaprion brevirostris, may produce 20,000 teeth in its first 25 years, and may live as long as 50 years.

The winner of the most-teeth contest are land and sea snails which usually have between 10-15,000 teeth, though some may have up to 25,000. This includes snails in the ocean off the North American coasts.

Studies of the European garden snail (Cornu aspersum), an alien in North America, indicate it has 14,000 teeth. Take a look at his toothy mouth under a microscope and find out why snails have so many teeth at NMH.org: Microscopic look at snail jaws.

European garden snail (photo from Wikimedia Commons)

p.s. Amazingly, the most abundantly land snail found in Pennsylvania, Zonitoides arboreus, has no teeth at all!

Quick gloss snail, Zonitoides arboreus, Edgewater, Maryland (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 Oceana.org

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)

Looking Back: Solastalgia For Birds

(photo from Wikimedia Commons)

6 September 2022

During fall migration bird numbers are at their highest as the adult population is joined by their recent young. I look forward to the variety of fall warblers and large flocks of chimney swifts, but this year — again — there are fewer migrants than I remember. My mood is dampened by solastalgia for birds.

Solastalgia is a new concept developed to give greater meaning and clarity to environmentally induced distress. As opposed to nostalgia–the melancholia or homesickness experienced by individuals when separated from a loved home–solastalgia is the distress that is produced by environmental change impacting on people while they are directly connected to their home environment. 

— US NIH: Solastalgia: The distress caused by environmental change

A 2019 bird population study headed by Cornell Lab of Ornithology quantified what I’ve been sensing. In the 50 years since 1970 North America’s total population of birds dropped by 3 billion. However it feels more recent because it has not been gradual. Half of that loss occurred in the past 15 years.

Fourteen years ago I noticed a decline in common nighthawks (Chordeiles minor) that used to migrate in flocks of 10-20 over my old neighborhood during the 20th century. In 2008 their numbers dropped precipitously. Nowadays I am lucky to see a single bird.

Common nighthawk (photo by Chuck Tague)
Common nighthawk (photo by Chuck Tague obtained in 2015)

Chimney swifts (Chaetura pelagica) were my consolation but now they prompt solastalgia. Two years ago I counted more than 2,200 swifts roosting at Cathedral Mansions chimney during fall migration, but just last year their numbers declined sharply. My highest count in 2021 was only 100. Fifty is my highest count so far this year.

Chimney swift trio (photo by Jeff Davis obtained in 2013)

Solastalgia is aptly summed up: “Sometimes you leave a place. Sometimes it leaves you.

Despite the sense of loss it is still good to be outdoors, it is still lovely to look at birds, and it is healthy to let go of the past and gracefully embrace the present.

For more information on bird decline and some good vibes for the future see 3billionbirds.org.

(see photo captions and links for the credits)

Songbirds Came From Australia

Northern cardinal, singing (photo from Wikimedia Commons)

31 August 2022

Songbirds (Oscines) are the majority of the world’s birds as you can see circled on the supertree below. In August 2016 we found out that all of them originated in Australia. Here’s how it happened.

Phylogenomic supertree of birds, a clockwise spiral from oldest to newest, marked with Australian origins (image from MDPI, July 2019)

The world was a very different place during the Oligocene 35 million years ago. For one thing there was a big gap between Australia and Asia and songbirds’ ancestors could not leave Australia.

Geography of the Oligocene from Wikimedia Commons

Then about 25 million years ago a land bridge formed when tectonic activity forced a patch of islands called Wallacea to the ocean’s surface. Wallacea, now part of Indonesia, bridged the gap and was the first step on the songbirds’ journey. (Ancient Wallacea in yellow below.)

Map of ancient Wallacea from Wikimedia Commons

They made the journey in flying steps, reaching the Western Hemisphere before Eurasia:

  1. Australia (label C below)
  2. Wallacea, an island group in Indonesia (label D)
  3. Southeast Asia and India (label E)
  4. Sub-Saharan Africa (label F)
  5. The Americas (label G)
Steps of songbird radiation from Australasia (map from “Tectonic collision and uplift of Wallacea triggered the global songbird radiation, Nature Communications, 30 Aug 2016) annotation: Wallacea “D” is circled in white

Like this…

Some songbirds were so successful that their DNA is found at each stop in living species across the world. Corvids are one such group.

Common raven, Yosemite (photo from Wikimedia Commons)

Others, like waxwings (Bombycillidae), have few DNA traces to show the path they took. Waxwings’ living DNA relatives are found only in Wallacea, North America and northern Eurasia.

Cedar waxwing (photo by Cris Hamilton)

Learn more about songbirds’ amazing journey in these articles:

(blank world map from Wikimedia Commons. photo and remaining maps are credited in the captions, click on the links to see the originals)

Air Pollution Confuses Bees and Butterflies

Honeybee on wingstem (photo by Kate St. John)

18 August 2022

We know that air pollution hurts humans. It is also bad for agriculture in an unexpected way. A study published in early 2022 by the University of Reading revealed that air pollution confuses bees and butterflies and reduces their pollination efforts.

Scientists from the University of Reading, the UK Centre for Ecology & Hydrology, and the University of Birmingham found that there were up to 70% fewer pollinators, up to 90% fewer flower visits and an overall pollination reduction of up to 31% in test plants when common ground-level air pollutants, including diesel exhaust pollutants and ozone, were present.

Technology Networks Applied Sciences: Pollination Reduced As Bees and Butterflies Confused by Air Pollution

The pollutants react with and change the scents of flowers, making them harder to find. “It can just make them not smell anything at all,” said lead author James Ryall.

Perhaps the bees are also confused by the load of particulate pollution that clings to their bodies via static electricity. Read more below.

Air pollution is not just bad for us, it’s bad for our food supply.

(photo by Kate St. John)

World’s Largest Petrified Tree?

Devils Tower, Wyoming (photo from Wikimedia Commons)

16 August 2022

Have you ever seen the Devils Tower in northeastern Wyoming?

I had no idea it existed until Allison Cusick displayed a photo and jokingly described it as the world’s largest petrified tree during his presentation on Botanical Superlatives. I’ve never been there but I was hooked.

The origins of this gigantic “tree stump” are as amazing as its appearance.

Devils Tower National Monument, Wyoming (photo from Wikimedia Commons)

Though no one knows for sure, most geologists agree that it’s a magma intrusion — not a volcano — of rare igneous rock called phonolite porphyry that formed 50 million years ago. At first it was buried underground but erosion has exposed it to stand 1,267 feet above the Belle Fourche River.

Devils Tower National Monument geologic cross section from Wikimedia Commons

The National Park Service describes it as the largest example of columnar jointing in the world.

Closeup of rock columns at Devils Tower (photo from Wikimedia Commons)

The Devils Tower is important to Native American culture and was established as the first National Monument in 1906 by President Theodore Roosevelt. It is one of the few monuments that allows rock climbing.

No it’s not a petrified tree.

Click here for a stunning photo of the Milky Way over Devils Tower at APOD.

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

Fossil in Schenley Park

Closeup #1 of fossil in Schenley Park (photo by Kate St. John)

10 August 2022

Sometime this summer the Department of Public Works placed a large sandstone rock at the base of the stairs behind the Schenley Park Visitors’ Center. The prominent fossil facing the stairs tells a story about life in Pittsburgh 300 to 330 million years ago.

Fossil rock at the base of the WPA stairs, Schenley Park, 6 August 2022 (photo by Kate St. John)

During the late Carboniferous period, while this rock was still sand, a Lepidodendron tree fell on it. Lepidodendron had scales on its branches and trunk that left impressions in the sand, illustrated below in increasingly fine detail.

Lepidodendron artist’s rendering (illustration from Wikimedia Commons)
Lepidodendron trunk or branch and resulting fossil impression (illustration from Wikimedia Commons)

The sand became sandstone and in the early 21st century the rock separated from its fellows thereby exposing the fossil. This rock many have fallen at the Bridle Trail rockslide.

Locations of two closeup photos of the fossil in Schenley Park (photo by Kate St. John)
Closeup #2 of fossil in Schenley Park (photo by Kate St. John)

I have never seen Lepidodendron’s closest living relative, Lycopodium, in Schenley Park …

Lycopodium (ground pine or club moss), Laurel Ridge State park, 30 May 2022 (photo by Kate St. John)

… but I’ll look for it now that I’ve seen its fossil ancestor.

Thank you to Public Works for placing this fossil rock on display in Schenley Park.

p.s. If this Lepidodendron had fallen in a swamp instead of on a sandy beach, it would have become coal. Read about similar fossils at Ferncliff Peninsula in Ohiopyle State Park in this vintage article: Fossils at Ferncliff

(photos by Kate St. John, illustrations from Wikimedia Commons; click on the captions to see the originals)

Common Birds, Exotic Ranges

House sparrow flock in England (photo from Wikimedia Commons)

8 August 2022

Birds move around on their own but some of our most common species came from a different continent or a different habitat and were introduced here by humans. Now you can see both native and exotic ranges in eBird after they made changes this month to the species maps.

House sparrows and pigeons, both introduced from Europe, are a case in point. In the eBird maps below native range is purple, exotic range is orange.

Introduced to cities: House sparrow (Passer domesticus)
Domesticated and introduced: Rock pigeon (Columba livia)
Feral rock pigeon (photo from Wikimedia Commons)
Explore Species Maps: European Starling (screenshot from eBird)
Reverse journey to Europe: Canada goose (Branta canadensis)

We tend to think that all exotic species were introduced from Eurasia to the Americas. Canada geese made the reverse journey. Europeans actually wanted them. Are they regretting that decision?

Canada geese in Hesse, Germany (photo from Wikimedia Commons)
Exotic on its own continent: House finch (Haemorhous mexicanus)

Captured house finches were illegally transported from California to New York City in the 1940s to be sold as “Hollywood finches” in the pet trade. Just before the law caught up to them, the vendors released the birds on Long Island. The “exotic” house finch population has now spread across the continent. eBird shows it on the map below. Click here and scroll down to see how they spread through the decades.

Male house finch (photo by Marcy Cunkelman)
Exotic within its native range: Northern bobwhite (Colinus virginianus)

The northern bobwhite does not do well in urban and suburban habitats but as a game bird it is raised in captivity and released for hunting in gamelands, agricultural fields and open woods. Have you seen a bobwhite in your backyard? It is an escapee within its “exotic” range.

Northern bobwhite (photo from Wikimedia Commons)
Northern bobwhite range map from eBird; Checkmark in the blue circle to remove escapees from map

Learn more about the new eBird maps at Important Changes to Exotic Species in eBird.

(photos from Wikimedia Commons and Marcy Cunkelman, screenshot maps from eBird; click on the captions to see the originals)

July: If You Can’t Clean Feeders Every Week, Stop Feeding Birds

House sparrow at bird feeder (photo from Wikimedia Commons)

13 July 2022

Mid to late summer is a good time to be a bird in Pennsylvania. Fruit is ripe, seeds are plentiful, insect food is everywhere and for raptors there are plenty of naive young animals to capture. With so much natural food available and with songbirds’ preference for insects in summer, birds are not dependent on backyard feeders in July.

You can safely bring in your bird feeders now. In fact, if you cannot clean your feeders every week, they are unsafe for birds. Highly pathogenic avian flu has ebbed this summer but there is apprehension that it will return during fall migration. And it’s not the only disease that kills birds.

Yesterday I encountered three dead or dying birds in my neighborhood within half a mile of each other: a house finch that fell over unless it propped itself on open wings, a dead fledgling robin standing in the street (below), and a fluffed house sparrow that could not walk.

Frozen in place: dead American robin fledgling standing in the street, 12 July 2022 (photo by Kate St. John)

I have no idea what was killing them. It could have been a different reason for each species. I do know that if it was contagious, finches and sparrows would have spread it at bird feeders.

Clean your feeders every week. In hot weather clean your hummingbird feeder twice a week because the nectar spoils! Are you leaving on vacation? Bring your feeders in so you don’t lure the birds into an unsafe environment.

Feeder cleaning advice from Audubon Society of Western PA, April 2022

Be kind and thoughtful of your backyard birds by keeping your feeders clean.

(photos from Wikimedia Commons, ASWP and Kate St. John)

Bird-Tag Tracks Beachcomber to London

Cata beach on Sanday, the Orkneys (photo from Wikimedia Commons)

27 June 2022

Solar-powered GPS tracking devices for birds can be so accurate that researchers can tell the bird’s location to within 100 meters. The devices keep transmitting even if they fall off, so when a beachcomber collected a discarded tag on a beach in Orkney it tracked him too.

Last winter researchers at University of Exeter attached GPS tracking devices to 32 Eurasian oystercatchers (Haematopus ostralegus) in County Dublin, Ireland to find out how the birds use the public lands. This spring one of the oystercatchers migrated to its breeding grounds on Sanday, Orkney Islands, Scotland. Its tag fell off on the beach on 7 April. The tracker kept transmitting.

Eurasian oystercatcher on the beach (photo from Wikimedia Commons)

At the end of May the tracker started moving again. It visited a campsite and a pizza shop, flew from Edinburgh to Heathrow and came to rest on a residential street in Ealing, London. Stuart Bearhop, Professor of Animal Ecology at the University of Exeter’s Centre for Ecology & Conservation, tweeted this plea for the tag’s return.

“The tags are worth around £1,000 each, so pretty pricey!” said PhD student Steph Trapp who is carrying out the research. “Any we can get back will be really valuable for increasing our sample size and the amount of data we can collect.” 

ITV news: London home unwittingly tracked by GPS bird tag left on remote Orkney beach

News spread quickly. A BBC Radio Five Live listener volunteered to leaflet the Ealing neighborhood. The beachcomber learned what he had collected and was happy to return the tag. Read how the Mystery of Orkney bird tag tracked to London is solved.

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