Birds (class Aves) are bipedal, warm-blooded, egg-laying vertebrate animals. Birds evolved from theropod dinosaurs during the Jurassic period and the earliest known bird is the Late Jurassic Archaeopteryx. Ranging in size from tiny hummingbirds to the huge Ostrich and Emu, there are around 10,000 known living bird species in the world, making them the most diverse class of terrestrial vertebrates.
Modern birds are characterized by feathers, a beak with no teeth, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a lightweight but strong skeleton. All birds have forelimbs modified as wings and most can fly, though the ratites and several others, particularly endemic island species, have lost the ability to fly. Birds also have unique digestive and respiratory systems that are highly adapted for flight.
Many species of bird undertake long distance annual migrations, and many more perform shorter irregular movements. Birds are social and communicate using visual signals and through calls and song, and participate in social behavior including cooperative hunting, cooperative breeding, flocking and mobbing of predators. Birds are primarily socially monogamous, with engagement in extra-pair copulations being common in some species - other species have polygamous or polyandrous breeding systems. Eggs are usually laid in a nest and incubated and most birds have an extended period of parental care after hatching.
Birds are economically important to humans: many are important sources of food, acquired either through hunting or farming, and they provide other products. Some species, particularly songbirds and parrots, are popular as pets. Birds figure prominently in all aspects of human culture from religion to poetry and popular music. About 120-130 species have become extinct as a result of human activity since 1600, and hundreds more before this. Currently around 1,200 species of birds are threatened with extinction by human activities and efforts are underway to protect them. Read more ...
'Hidden Gem' Fossil Of Dinosaur Skin Preserved Like Glass Reveals It Had Scales And Feathers IFL Science - May 21, 2024
A new fossil of the partially feathered dinosaur Psittacosaurus has revealed that these animals had bizarre skin that included both bird-like feathers and reptile-like scales. The first-of-its-kind fossil provides new insights into the evolution from scales to feathers, demonstrating that these animals exhibited 'zoned development' in their skin. The first Psittacosaurus fossil was discovered in 1922, but a more recent discovery was able to reveal - for the first time - quite how peculiar their skin was. Dating back to the early Cretaceous, between 135 and 120 million years ago, it lived at a time when dinosaurs were starting to evolve into birds.
150 Million-Year-Old Dinosaur Had Uniquely Long Legs Never Seen Before IFL Science - September 7, 2023
Paleontologists May Have Found A Missing Branch Between Dinosaurs And Birds Science Alert - September 7, 2023
How Did Birds Get Wings? We May Have Found The 'Missing Link' in Dinosaur Fossils Science Alert - February 28, 2023
Dinosaur fossils featuring arms with a suspect bend at the elbow and wrist could hint at the presence of an unpreserved tendon that underpins all modern avian flight. The evolution of wings powerful enough to lift a vertebrate off the ground is one of the greatest mysteries in paleontology. Pterosaurs are famous for being the earliest known vertebrates to achieve true lift-off nearly 200 million years ago. Yet these massive ancient reptile weren't dinosaurs, leaving the direct ancestors of birds to figure out the whole flying business all on their own. Avian dinosaurs would only evolve much later from two-footed, feathered theropods - 80 million years or more after pterosaurs had already achieved powered flight.
This Ancient Creature Is a Bizarre Hybrid of Dinosaur And Bird Science Alert - January 5, 2023
We can confidently say that birds are dinosaur descendants, though paleontologists are still puzzled as to how this incredible evolutionary event occurred. Now a complete fossilized skeleton of a bird that lived in what is today China around 120 million years ago might help clarify key steps in the transformation process, presenting with a more archaic, dinosaur-like head atop a body that has more in common with modern birds.
New fossil foot analysis reveals the surprising and varied lifestyles of dinosaur bird ancestors PhysOrg - December 21, 2022
For more than 25 years, extraordinary fossils of feathered dinosaurs have been emerging at a tremendous rate from Early Cretaceous (roughly 145 million to 100 million years ago) rocks in China. Fossilized feathers on a slew of species show precisely how feathers changed over time. They transitioned from simple hair-like filaments in ground-dwelling theropods to branching and increasingly more complex modern-style feathers in pennaraptorans (the group most closely related to and including birds), and finally birds themselves. But feathers are only half the story.
Newly Discovered Dinosaur Looks Like a Nightmare Goose Gizmodo - December 2, 2022
Paleontologists discovered a 71-million-year-old carnivorous dinosaur in Southern Mongolia that they believe had a body built for swimming and diving for prey. Though it looks a lot like a modern bird, it’s actually a non-avian dinosaur, meaning it's likely an example of convergent evolution, a phenomenon in which unrelated creatures evolve similar traits.
This Tiny, 120-Million-Year-Old Fossil Has a T. Rex-Like Skull on a Bird Body Science Alert - June 27, 2021
A tiny, 120 million-year-old fossil, discovered in northeast China, is neither bird nor dinosaur but is perched on its own evolutionary branch, somewhere in between. While the 2-centimeter-long (0.75-inch) skull of this little fella holds similarities to much larger dinosaurs like Tyrannosaurus rex, its thin and delicate body looks more like modern-day crown birds, such as sparrows or hummingbirds.
Baby bird fossil is 'rarest of the rare' BBC - March 5, 2018
The chick lived 127 million years ago and belonged to a group of primitive birds that shared the planet with the dinosaurs. Fossils of birds from this time period are rare, with baby fossils seen as "the rarest of the rare". Scientists say the discovery gives a peek into the lives of the ancient, long-extinct birds that lived between 250 and 66 million years ago.
Fossils of 75 million-year-old dinosaur that looked like a mutant swan with a reptilian tail are found by stunned archaeologists in Mongolia Daily Mail - December 7, 2017
A bizarre feathered dinosaur resembling a nightmarish mutant swan has been identified by scientists. The strange creature had a graceful swan-like neck but also scythe-like claws, a reptilian tail, and a beak lined with teeth. Halszkaraptor escuilliei, which lived 75 million years ago, was about the size of a modern swan and is thought to have been semi-aquatic.
How did dinosaurs evolve beaks and become birds? Scientists think they have the answer PhysOrg - September 28, 2017
Once you know that many dinosaurs had feathers, it seems much more obvious that they probably evolved into birds. But there's still a big question. How did a set of dinosaurian jaws with abundant teeth (think T. rex) turn into the toothless jaws of modern birds, covered by a beak? Two things had to happen in this transition, suppression of the teeth and growth of the beak. Now new fossil evidence has shown how it happened.
66 Million Years Ago, Bird-Like Dinosaurs Laid Blue-Green Eggs Live Science - August 31, 2017
A type of bird-like dinosaur that lived in what is now China during the Cretaceous period - about 145.5 million to 65.5 million years ago - laid eggs that had a bluish-green tint, the first evidence of pigment in dinosaur eggs, according to a new study. The well-preserved eggshells belonged to the oviraptorid Heyuannia huangi, and analysis revealed the hints of blue-green color, the researchers said. Oviraptorids were a small-bodied, short-snouted group of dinosaurs with toothless beaks, and are known from fossils found in Mongolia and China. Blue and green egg hues are found in eggs belonging to many types of modern birds, and were long thought to have originated in bird lineages. This new finding, however, implies that egg coloration appeared earlier in the dinosaur family tree, and might have emerged alongside nesting behavior that left eggs partially exposed in nest mounds, rather than buried underground.
Dino-bird fossil had sparkly feathers 'to attract mate ' BBC - November 15, 2016
An extinct bird that lived about 120 million years ago had iridescent feathers that it may have used to attract a mate, fossil evidence shows. The prehistoric bird, which was found recently in China, may have puffed up its feathers like a peacock. The bird's feathers are "remarkably preserved", including the chemical that gave them sparkle. The animal belongs to a group of early birds known as enantiornithines, which lived during the Age of the Dinosaurs. All known specimens come from rocks in Liaoning, China, which have yielded numerous fossils of feathered dinosaurs, primitive birds and pterosaurs.
Ancient birds' wings preserved in amber BBC - June 28, 2016
Two wings from birds that lived alongside the dinosaurs have been found preserved in amber. The "spectacular" finds from Myanmar are from baby birds that got trapped in the sticky sap of a tropical forest 99 million years ago. Exquisite detail has been preserved in the feathers, including traces of color in spots and stripes. The wings had sharp little claws, allowing the juvenile birds to clamber about in the trees. The tiny fossils, which are between two and three centimeters long, could shed further light on the evolution of birds from their dinosaur ancestors.