Blog #395 The Dino-Days

What a difference a week, let alone two weeks, make. At 10 to 12 days old, the hatchlings’ buff-colored down was replaced with a dense, wooly second down which will last another 10–15 days. Lani (13 days old), Makani

The hatchlings in their first week lined up for a feeding.

 

Orpheus feeding week-old hatchlings.

 (15 days old), and Moana (17 days old) have entered the transitional and rather disproportionate-looking Reptilian phase. At this stage, they have oversized bluish-grey feet with long, black talons and enormous beaks. The dark, scaly hatchlings with prehistoric-looking deep orange eyes, 

Moana, day 15, is in his/her reptilian phase.

have crops that bulge during mealtimes and pin feathers that stick out all over their bodies. The young know to crouch at danger, suggestive of their ancient theropod lineage of the Cretaceous period, 65 

The three hatchlings huddle in reaction to the parent’s alarm calls.

million years ago...and in Michael Crichton’s Jurassic World. Not all dinosaurs went extinct at the end of the Cretaceous Period. One group survived, and we are fortunate to see their descendants daily—modern birds. 

Feeding the Reptilian-phased hatchlings.

The sudden extinction of non-avian dinosaurs at the end of the Cretaceous has intrigued paleontologists. Discoveries have included shared skeletal features like hollow bones and hips that allow walking upright as well as dinosaur fossils showing feathers and nesting grounds. New finds continue to fill in the bird family tree and shed light on ancient dinosaur behavior.

The widely accepted theory is that an asteroid impact 65 million years ago off the coast of Mexico generated massive tsunamis, with impact debris cutting off sunlight for months, stopping photosynthesis, and causing freezing temperatures. Chemical reactions in the atmosphere caused acid rain and long-term global warming, all of which extinguished non-avian dinosaurs. Contemporaneously, massive lava flows erupted across what is now southwest India. The eruptions probably caused many of the same effects as the asteroid impact. Although most scientists believe that the impact was the final blow for non-avian dinosaurs, both events could well have played a role. 

Most paleontologists have accepted for decades the idea that birds are living dinosaurs. But the discovery of the Bambiraptor has led to some intriguing new ideas about the strong links between birds and dinosaurs. Bambiraptor was probably covered in feathers, and its skeleton was almost identical to that of a modern bird. Even though Bambiraptor was only two feet long and weighed five pounds, it was a vicious raptor that hunted and ate other dinosaurs. 

Model of Bambiraptor, courtesy of SciNews.

Bambiraptor belongs to the group of dinosaurs called dromaeosaurs, which are closely related to modern birds. Dromaeosaurs had feathers and other features like hollow bones that are important for flight. But these dinosaurs could not fly because their limbs were too short to function as wings. Feathers also evolved first in dinosaurs that lived on the ground or climbed trees. These traits were only later used for flight.

Roadrunner, courtesy of Chicago Zoological Society.

A modern Roadrunner is similar to Bambiraptor: it has an S-shaped neck, a pubis bone in the hip that points backward, a V-shaped wishbone, folding arms, and three primary toes.

Eyes to the sky!

Candace

Candace E. Cornell 

cec222@gmail.com

On Osprey Time will soon be moving to a new address. See Blog #396.

Peaceful brooding at Salt Point during sunset.