Every autumn humpback whales (Megaptera novaeangliae) migrate past California on their way to spend the winter off the coast of Mexico. They will linger, however, if they find lots of anchovies. Humpback whales love anchovies.
There were still lots of anchovies when the whales showed up this fall. Robin Agarwal took a whale watch out of Monterey Bay in early October and captured these scenes of lunge-feeding humpback whales.
The anchovies crowded close as the predators approached. The whales forced them to the surface where the tiny fish leapt out of the water to escape.
The whales opened their mouths and anchovies fell in.
About ten years into his career as a digital cartographer Robert Szucs decided to experiment with data visualization and learned how to create strikingly beautiful, digitally accurate maps. He calls them “Maps Reimagined” and explains,
While my maps are always scientifically accurate, I think of them first and foremost as works of art.
The U.S. watershed map above is so detailed that you can pinpoint Pittsburgh in the Mississippi watershed at the conjunction of the Allegheny, Monongahela and Ohio Rivers.
Szucs has also produced collections of elevation, forest and human population maps.
There came a point when I said I can’t look at another green-brown-white elevation map again. I needed some fun. I needed colours. And for not the first or last time, I needed to create the maps I wanted to see.
When we think of the beach in winter it sounds pretty bleak but not if you’re a birder. Shorebirds, sea ducks, loons and gulls leave the icy north to winter on the Atlantic and Pacific coasts where they hang out on beaches or just offshore, especially near jetties.
If you can’t travel far from Pennsylvania, visit the New Jersey shore to see thousands of wintering birds. GetToKnowNature describes what you’ll see in her video “Welcome to the beach in winter.” Click here or on the screenshot below to see it on Instagram (you don’t need an account to see it) or here for YouTube.
(photo from Wikimedia Commons, screenshot from GetToKnowNature video on Instagram)
Tundra swans pass over Pittsburgh in mid November but rarely stop on their way to the Chesapeake and Tidewater North Carolina. I missed seeing them overhead in Pennsylvania so while in Virginia this week I went to visit them at their winter home.
Tundra swans (Cygnus columbianus) breed in the arctic wetlands of Russia, Alaska and Canada and spend the winter in temperate marshes and grasslands, often near the coast.
The internal spinning keeps the core in shape and allows it to continue traveling long after other bubbles have dispersed.
Dolphins and whales purposely produce bubble rings from their blow holes and play with them. They examine and prod the rings, roll them like wheels, speed them up, or nudge them until a smaller ring splits off. They will even bite or swallow the ring or swim through it if it’s large enough.
Divers familiar with the wild animals probably knew about this long ago. The rest of us saw it for the first time at aquariums. Here are some videos.
Video from 2008:
Video from 2010 at Sea World:
p.s. Though scientists have written about dolphins and bubble rings for at least 50 years, BBC Earth published a video only 8 months ago in which a scuba diver placed a bubble machine underwater and filmed the dolphins’ reactions. The narrated script says the dolphins are afraid of the manufactured bubbles and have to learn to be brave. Apparently, the producer was not aware dolphins already know about bubble rings, so why would they be afraid? Sigh. It’s a good example of why you cannot believe everything you hear on TV. Stay curious!
(photos and animation from Wikimedia Commons; click on the captions to see the originals. videos embedded from YouTube)
Sea level is rising overall about 3 millimeters (0.1 inches) per year due to climate change but Chesapeake Bay is rising even faster than the ocean — as much as 4.6 millimeters per year — because the area is still subsiding after the last Ice Age. Some Chesapeake Bay islands are disappearing.
Just across the Virginia line (at the bottom of the satellite images) is Tangier Island whose land mass has shrunk 67% since the 1850s. Its population shrank as well. By now Tangier has only 345 acres and a population of about 470.
Residents are routinely flooded during the highest tides, pictured at top and below.
A 2015 analysis by the U.S. Army Corps of Engineers predicted that Tangier Island will become uninhabitable within 25-50 years, about mid-century.
Tangier Island will eventually join Great Fox Island under the bay.
Another favorite dolphin game is to ride the pressure wave at the front of a fast moving boat. Called “bow riding,” the bow wave pushes dolphins fast forward without any flapping on their part.
Dolphins like this game so much that they rushed toward the whale watch boat. Robin Agarwal says of this photo, “Pacific White-sided Dolphins and Northern Right Whale Dolphins stampeding towards the boat to bow ride – my favorite sight in the world.”
Here they are bow riding with an “unusual swirl color morph” among them.
Though they breed in the arctic around the world, the North American population stays west of the Mississippi. These geese are rare in Pennsylvania.
Their “greater” and “white-fronted” adjectives don’t make much sense unless you know the species they resemble in Europe.
They are “greater” because they are larger than the lesser white-fronted goose (Anser erythropus) that occurs only in Eurasia and is now Vulnerable to extinction.
They are “white-fronted” because they have white feathers on their faces surrounding their beaks, a field mark that distinguishes them from the similar greylag goose (Anser anser), another Eurasian species.
Only a handful of greater white-fronted geese are seen in western Pennsylvania in any given year, and then only in late October through early March.
If you see a goose that resembles this one check its field marks carefully. It may be an odd domestic goose, described here:
(images from Wikimedia Commons, map embedded from allaboutbirds.org)
This week Charity Kheshgi and I saw ring-billed gulls (Larus delawarensis), a common merganser (Mergus merganser) and a few pied-billed grebes (Podilymbus podiceps) at Duck Hollow. All three species visit the Monongahela River in November when freshwater freezes up north.
The common merganser gave us an opportunity to mentally compare her field marks to a similar bird. Here are some tips.
Female common and red-breasted mergansers are so similar that it takes some practice to tell them apart. Charity’s photos show the common merganser’s two unique field marks:
A sharp demarcation between dark head versus white breast / gray back.
A sharply defined white under-chin.
Notice the common merganser field marks in three photos.
Female red-breasted mergansers (Mergus serrator) lack those sharp lines. The colors blend from one to the other.
Note that the presence of a head crest is not a reliable difference between the two; both can display it.
So here’s a quiz: Which species is in the photo below? Are these common or red-breasted mergansers?
In 1994 dozens of bald eagles were found convulsing, dead or paralyzed near Arkansas’ DeGray Lake. Autopsies revealed the eagles died of a new disease called avian vacuolar myelinopathy (VM) that manifests as brain lesions. The dying spread to Florida, Georgia, the Carolinas and Texas (hashed areas on the map below) and continues to this day. In 2021 scientists discovered what causes VM. It’s a chain of events that begins when we use an aquatic weed killer to control an invasive weed.
The invasive weed is hydrilla (Hydrilla verticillata) that spreads easily and clogs waterways. It’s a huge problem in many southeastern states, especially in Florida.
Integrated chemical plant management plans to control H. verticillata should avoid the use of bromide-containing chemicals (e.g., diquat dibromide). [The neurotoxin] AETX is lipophilic with the potential for bioaccumulation during transfer through food webs, so mammals may also be at risk.
(photos and diagram from Wikimedia Commons, map embedded from NIH; click on the captions to see the originals)
(*) The mystery was solved when scientists discovered that the toxin came from bromides that did not occur naturally. From NIH, Hunting the eagle killer: A cyanobacterial neurotoxin causes vacuolar myelinopathy: “Laboratory cultures of the cyanobacterium, however, did not elicit VM. A. hydrillicola growing on H. verticillata collected at VM-positive reservoirs was then analyzed by mass spectrometry imaging, which revealed that cyanobacterial colonies were colocalized with a brominated metabolite. Supplementation of an A. hydrillicola laboratory culture with potassium bromide resulted in pronounced biosynthesis of this metabolite. H. verticillata hyperaccumulates bromide from the environment, potentially supplying the cyanobacterium with this biosynthesis precursor.”