Scallops travel by opening and closing their shells but the direction they move seems counterintuitive. They don’t lead with their hinges. Instead the open edge goes first as they use their eyes to guide themselves.
Scallops’ eyes look like bright beads at the shells’ front edge.
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.
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.
Twitter can you please help? We have a tag that has fallen off one of @mindtheTrapp‘s oystercatchers. Someone visiting Orkney in the last few days seems to have found it and taken it to London. Can you please RT and/or get in touch if you think you can help us get it back! pic.twitter.com/a2IoXzI02h
“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.”
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)
Some birds change their feathers for the breeding season. Others change the color of their skin.
In the non-breeding season, June to December, the bare skin on anhingas’ (Anhinga anhinga) faces is an unremarkable yellowish-brown that blends with their plumage and beaks.
But beginning in January their bodies transition to breeding plumage and their faces turn bright turquoise. Even the normally dull, brown-necked females have resplendent blue-green around their eyes.
Watch their fancy faces in this video from South Carolina.
Avian influenza, also called bird flu, is in the news lately because a highly contagious strain has made it to North America from Eurasia. Though not dangerous to humans, this year’s strain is easily caught by some bird species, most notably chickens. Here’s what it is and what we can do to protect birds.
What is this virus?As USDA explains, “Avian influenza is caused by an influenza type A virus which can infect poultry (such as chickens, turkeys, pheasants, quail, domestic ducks, geese, and guinea fowl) and wild birds (especially waterfowl).” Various strains are always in the wild but the low pathogenicity versions do not cause illness in wild birds or chickens. Every few years, however, a highly pathogenic (HPAI) strain surfaces that is extremely infectious, fatal to chickens, and rapidly spreads in domestic poultry.
This year’s HPAI strain has already devastated many poultry farms.
Which birds have died? USDA is tracking the virus and reports that millions of commercially raised chickens and turkeys have already died this year. As of 7 April 2022 the total death count was more than 24.2 million, the vast majority of which — more than 16 million — were Commercial Layer Chickens. That’s why the price of eggs has gone up. (See USDA commercial and backyard flock statistics here.)
If you are a poultry farmer, have backyard chickens, or have captive birds in a zoo or rehab facility you’ll want to heed USDA’s advice to protect your birds. Accordingly the Pittsburgh Zoo, the National Aviary, and HARP’s wild bird rehab facility in Verona are taking precautions. (See this Post-Gazette article.)
Should we worry about wild birds? Not so much. Wild birds maintain their own social distancing whereas domestic poultry live in crowded conditions on factory farms.
In addition, avian flu is primarily caught by ducks, geese, swans, chickens, wild turkeys, pheasants and quail. Some raptors catch it, though in low numbers. Songbirds are at low risk.
As of 7 April 2022, USDA testing of dead wild birds has found 637 cases in the U.S. 88% were water-related birds, notably mallards and snow geese. 11% were raptors. The highest raptor death toll was among black vultures who roost communally. (See USDA wild bird statistics here.)
Notice the order of magnitude here: 24.2 million poultry deaths versus 637 wild bird deaths.
Interestingly, the species most susceptible to avian influenza are closely related and stand alone in the the phylogenomic supertree below (pale green branch at bottom right = ducks, geese, chickens, pheasants) while those least susceptible are least related to ducks and chickens.
And finally, here are two quotes from the New York Times:
Nearly all the nine billion chickens raised and slaughtered in the United States each year can trace their lineage to a handful of breeds that have been manipulated to favor fast growth and plump breasts. The birds are also exceptionally vulnerable to outbreaks of disease. “They all have the same immune system, or lack of an immune system, so once a virus gets inside a barn, it’s going to spread like wildfire,” said Dr. Hansen, the public health veterinarian.
Andrew deCoriolis, the executive director of Farm Forward says: “Instead of asking how factory farms can prevent infections that originate in the environment, which is how they frame it now, we should be asking how they can prevent infections that originate on factory farms,” he said. “If we keep raising more and more animals in these conditions, we should expect the exact outcome we’re getting because that’s how the system is set up.”
Les Leighton had his camera set up at Canada’s Vancouver harbor when a drama played out in front of him. A gull zipped by with both a bald eagle and peregrine falcon pursuing it in flight. What was it about that gull that attracted two predators at the same time?
Watch the chase and notice the difference between the eagle’s and peregrine’s hunting techniques. Why did both of them give up?
Intersex hen mallard, Duck Hollow, 20 March 2022 (photo by Michelle Kienholz)
22 March 2022
On Sunday at Duck Hollow we saw a female mallard with odd plumage. She was paired with a male mallard but she resembled a male in eclipse plumage. Was this duck a hybrid? Or was it something else?
Intersex hen mallard with her mate, Duck Hollow, 20 March 2022 (photo by Michelle Kienholz)
Michelle Kienholz was so intrigued that she took photos and sent them to the Duck ID group where she learned an amazing thing about female ducks. This odd mallard at Duck Hollow is an “intersex hen.” She is becoming male in a process called spontaneous sex reversal (SSR).
Female ducks are born with two ovaries but only one develops. The left ovary actively pumps out hormones to stifle the male genes, making the bird truly female. If a disease damages the only ovary and it stops producing hormones the female duck spontaneously turns into a male. Experiments have shown that the now-male duck is able to breed and fertilize eggs.
Because most ducks are sexually dimorphic a female with a dead ovary eventually looks male as well. The intersex hen at Duck Hollow is partway through her/his outward transformation, which is why she/he is in eclipse-like plumage.
Notice the clues in her/his feathers that indicate the transition:
tail feathers are black and curly white,
green feathers interspersed on head
breast is darkening (top photo)
color line between neck and breast is becoming white
Intersex hen: tail end is black with white feathers, green feathers on head (photo by Michelle Kienholz)Intersex hen, color line between neck and breast is becoming white (photo by Michele Kienholz)
For more information on bird sex chromosomes see Anatomy: W and Z. For photos of eclipse plumage see Mallards in Eclipse. And here is an article about spontaneous sex reversal in chickens, a problem for chicken farmers.
What looks like a glowing pincushion (above) or piece of plastic in the tweet below is an animal called a nudibranch. It’s not pronounced the way it’s spelled. The “ch” is a “k.” This is a “NEW-dih-brank.”
Nudibranchs are sea slugs whose name means “naked gills” though some of them have no gills at all. From a video at DeepMarineScenes I learned that nudibranchs are …
3000+ species of sea slugs similar to snails but without any shells inside or out,
Found from the poles to the tropics, most often in shallow tropical waters,
Carnivores that eat sponges, corals, anemones, etc.
Range in size from 1/4 inch to 1 foot long,
Use smell and feel to get around. Their eyes sense only light and dark.
Brightly colored from the toxic things they eat.
Toxic themselves. Their color warns off predators.
Their only real predators are other nudibranchs. Yow!
We think of mallards (Anas platyrhynchos) as dabbling ducks that eat plant material and bread tossed by humans(*) but these common ducks are actually omnivorous and opportunistic. Their diet depends on time of year.
On migration and in winter mallards are basically vegetarian, eating seeds, acorns, aquatic vegetation, cereal crops, and in urban areas human-provided bread and birdseed.
Fortunately small bird consumption is quite unusual and unnecessary. Males and non-laying females eat only 37% animal matter in the breeding season while laying females consume 71.9% animal matter to meet their energy needs.
I saw a pair of mallards mating at Panther Hollow Lake last weekend so I know the breeding season has begun in Pittsburgh. Laying females will be bulking up on snails, insects and worms.
Meanwhile most mallards are still on migration to their breeding grounds. They will change their diet soon.
