Strange and wonderful birds

I caught a bit of a nature show on birds: The Life of Birds, part N? with a David-Attenborough-like figure narrating. Some of the birds of New Zealand really caught my eye. Perhaps it’s just as well that the elephant bird or the terror bird are no longer around to dine on us; but it’s a shame that the giant coots, flightless parrots, kiwis, and other birds are so close to extinction.

And the hoatzin! I’d heard vaguely of a bird that had claws on its wings. But I never pictured the way the nestlings climb around on branches. They look very much like prehistoric birds just getting ready to use their feathers for the first time. Gliding from tree to tree has evolved much more often and in more animal taxa than pure flying.

The hoatzin is so adapted to eating masses of low-energy vegetation that it flies poorly. But its wings are well developed. The claws are a juvenile evolutionary trace.

Hope for horseshoe crabs

Falling numbers of migratory birds awakened the wildlife authorities in the eastern U.S. to the vital role that horseshoe crabs play in feeding them on their journeys. The crabs, an ancient lineage dating back 400 million years, were caught by millions to be cut up for bait, pet food, and even fertilizer. To protect them, or to protect their cute feathered predators, catching horseshoe crabs has been restricted or banned by nearby states. The numbers of crabs coming to the beaches to mate and lay eggs have slowly begun to rise from dangerously low levels. Perhaps it’s not too late for them, if people remember to refrain from killing them.

Horseshoe crabs serve another useful purpose. They react violently to meningitis bacteria, so their blood can be used to detect it. They also have a one-step blood-clotting mechanism, so they prove that blood clotting evolved gradually over eons.

Eagle cam

This web camera is focussed on an eagle’s nest. Currently, there’s at least one nestling. But turn down the sound a little: there’s traffic noise.

The Brackendale Eagle Sanctuary in British Columbia has a link to this webcam, stating that it is on Hornby Island. The island is close to Vancouver Island, in Georgia Strait between Vancouver Island and the mainland.

Platypus genome is sequenced

And now we have to put up with newspapers calling the platypus “part bird.” PZ Myers at Pharyngula lets off a little steam in his intro to the platypus genome:

Over and over again, the newspaper lead is that the platypus is “weird” or “odd” or worse, they imply that the animal is a chimera — “the egg-laying critter is a genetic potpourri — part bird, part reptile and part lactating mammal”. No, no, no, a thousand times no; this is the wrong message. … What’s interesting about the platypus is that it belongs to a lineage that separated from ours approximately 166 million years ago, deep in the Mesozoic, and it has independently lost different elements of our last common ancestor, and by comparing bits, we can get a clearer picture of what the Jurassic mammals were like, and what we contemporary mammals have gained and lost genetically over the course of evolution.

Go over and read what the new platypus genome actually tells us about the course of evolution.

Here’s a diagram showing the evolutionary splits. PZ will explain it.

Diagram notes:
Emergence of traits along the mammalian lineage.

• Amniotes split into the sauropsids (leading to birds and reptiles) and synapsids (leading to mammal-like reptiles).
• These small early mammals developed hair, homeothermy and lactation (red lines).
• Monotremes diverged from the therian mammal lineage 166 Myr ago and developed a unique suite of characters (dark-red text).
• Therian mammals with common characters split into marsupials and eutherians around 148 Myr ago (dark-red text).
• Mammal lineages are in red; diapsid reptiles, shown as archosaurs (birds, crocodilians and dinosaurs), are in blue; and lepidosaurs (snakes, lizards and relatives) are in green.
• Geological eras and periods with relative times (Myr ago) are indicated on the left. Myr = “Megayear” or million years.

PZ writes:

This is a fairly conventional picture of our evolutionary history, and I have to emphasize that this paper reinforces the evolutionary explanation for the illustrated relationships.

Scientific logic, executive summary:

if we find a feature in birds that is also present in monotremes, marsupials, or eutherians, it is likely that that feature was also present in our Paleozoic common ancestor….

For instance, one of the unusual (for a mammal) features of the platypus is meroblastic cleavage…. the early [cell] divisions are incomplete — they produce a sheet of cells on top of the large yolk that are cytoplasmically continuous with the yolk cytoplasm…. Birds (archosaurs) and lizards and snakes (lepidosaurs) exhibit meroblastic cleavage. [In contrast, marsupials and eutherians, exhibit complete cleavage from the first division. So] meroblastic cleavage is likely to be a primitive character, one that was inherited from the last common ancestor of synapsids and sauropsids, over 300 million years ago.

Go on and read more: why the platypus isn’t “wierd,” how its venom evolved, what other animals are being sequenced—you know you want to.

Stock photo of the day: Eurasian griffon vulture

I just stumbled upon this lovely image: Eurasian griffon vulture by Linda Wright.

City songbirds change their tune

Ed Yong of Not Exactly Rocket Science has an article in New Scientist: “City songbirds are changing their tune.” Their calls are becoming harsher, shorter, louder, and simpler. The next thing to find out is whether this is a change in dialect or a temporary change caused by the noise, like shouting in a factory.

See Ed’s blog post, “Ed’s Writing Causes End of Civilization?“

That’s a funny place to see a penguin

The BBC has released a new video of penguin behavior.

Sanderlings running on the beach

Sanderlings are a small species of sandpiper. One of the nicest things about visiting California is that sometimes we see the little sanderlings or perhaps least sandpipers running up and down the beach to pursue and then flee the waves. Grrlscientist at Scientist, Interrupted, has a very nice close-up picture of a running sanderling.

Liaoning fossils

I still don’t have access to my pictures of the fossils from China exhibit in Miami, but some of these look very familiar: “Dragons of Liaoning” on Discover (UPDATED) is about early fossil birds and shows the transition from protofeathers to feathers with shafts to flight feathers.

‘Sleeping Dragon’ posture

Mei Long, the Soundly Sleeping Dragon, is a fossil of a juvenile troodont that demonstrates another link between birds and these dinosaurs. It died in a curled, heat-preserving posture, apparently in its sleep — with its head tucked beneath its forelimb. The posture immediately recalls birds sleeping with head tucked under wing. PZ Myers at Pharyngul has the details and diagrams in his 2004 article, “Mei Long, the Sleeping Dragon.”

Super-raptors at Tetrapod Zoology

Darren Naish at Tetrapod Zoology gives us a run-down on some of the giant raptors that have developed in island ecosystems.

Travel day: Florida to Georgia

Today we drove north from Coral Springs, Florida, to Savannah, Georgia. We took the scenic route part of the way: up some of the coastal islands from Daytona Beach.

On the way up the coast, we saw a couple of sandhill cranes. LotStreetWiz spotted and a roosting osprey by the side of the road.

We reached St. Augustine, Florida (founded 1635) about the time it got dark. There’s the remnants of an old and grim fort there.

We switched back to the main highway. It was dark enough between cities that I could see a lot of stars; in fact I thought I could see the Milky Way, but we didn’t stop for a look.

Dinosaurs of China progress report

I’m back from the Dinosaurs of China exhibit in Miami, which was freakin’ awesome. Pictures were allowed and I took about 500, of which maybe 3 - 5 will be posted. But if you have a question about Chinese dinosaurs, drop me a comment or e-mail and I’ll see if I have something that illustrates it. I tried to take heads, hips, shoulder girdles, feet, etc. as well as whole animals. Small specimens were in glass cases and I don’t yet know how well autofocus (or my attempts to outsmart it) worked.

There was a herd of large Chinese dinosaurs that were unfamiliar to me, plus specimens of early birds Microraptor gui, and some other taxa (fish, insects) and plants.

One of the reconstructed dinosaurs, Dilong paradoxus, is shown in this unrelated image as a bony joint surrounded by traces of its feathers. Because Dilong was feathered, we know that T. rex was probably feathered, at least in the juvenile stage.

Dinosaurs of China

I’ll be off to see the dinos as soon as my camera battery recharges. The Miami marathon is on today so I’ll be avoiding the running route if possible.

The Dinosaurs of China are at the Miami Science Museum: “14 enormous articulated dinosaur skeletons and 52 spectacular individual specimens, including 8 of the most rare feathered dinosaurs and birds from the fossil beds at Liaoning.” More on my visit later.

Florida Everglades: Loxahatchee National Wildlife Refuge

We just got back from a three-hour visit to Loxahatchee National Wildlife Refuge on the northeastern edge of the Florida Everglades. We were allowed to gaze from an observation deck at the real everglades. And we walked happily around earthen dikes of water impoundment areas where waterfowl were plentiful.

The impoundment areas are a test patch of the Everglades ecosystem. Sections are separated by dikes, and the researchers control the water levels to maintain healthy growth of the Everglades vegetation, produce plentiful wild food for native fauna, and discourage invasive species.

We saw broad-winged hawks, black vultures, great blue herons, great white herons, little blue herons, tri-coloured herons, cormorants or anhingas, possibly a green heron, possibly limpkins or wood storks, some dark heron-like birds, egrets, possibly ibises, coots, marsh hens, gallinules, lizards, turtles, and a few alligators basking in the sun. The alligators look at first glance like old tire treads. LotStreetWiz saw a dark snake about five feet long, which whipped away before I saw it.