There have been quite a few interesting stories about birds, both ancient and modern, these last few weeks so consider this post to be a combination of paleontology and nature news! As usual I will begin with the oldest species and work my way forward in time.
Ever since the first discovery of Archaeopteryx in 1861 most paleontologists have placed the evolution of birds from their dinosaur kin as having happened during the Jurassic period some 145-150 million years ago. A minority of paleontologists have disagreed however, Archaeopteryx, with its mouth full of teeth and a long bony tail is really a lot more like a dinosaur with feathers than a bird, and with no other recognized bird species in the Jurassic the initial evolution of the birds has remained controversial.
A recent fossil discovery from the southeastern Chinese province of Fujian may help to fill in some of the gaps however. In rocks dating back to 149 million years ago researchers from the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences have found a new species of Jurassic bird to complement Archaeopteryx. Their results have been published in the journal Nature.
The find, which has been given the name Baminornis zhenghensis, consists of a bird like shoulder and pelvic bones along with a hand structure more dinosaur like than avian. Most importantly B zhenghensis possesses a short tail ending in a bony structure called a pygostyle that is a feature in some modern birds and is common among birds from the Cretaceous period that followed the Jurassic. In the analysis performed by lead author Wang Min and his colleagues B zhenghensis is considered to be a relative of archaeopteryx while at the same time having a closer relationship to the more modern birds of the later Cretaceous period.
It was during the Cretaceous that the number of bird species grew considerably with recognizable types making their first appearance. In fact a fossil skull that was collected in Antarctica in 2011 has recently been analyzed and classified as a waterfowl, the ancestor of modern ducks and geese. Dated to 69 million years old the skull has been given the name Vegavis iaai. Like the researchers in China who discovered B zhenghensis, the paleontologists who discovered V iaai hope that their find will shed new light on bird evolution.
So much for ancient, i.e. fossil birds now let’s move forward in time to the present because there’s some interesting news about a species of modern bird as well. We all know that many types of birds like to live in large groups that we’ve named flocks. Ducks and geese, pigeons, starlings and penguins are some of the many bird types that live in flocks while other types of birds like eagles, owls and blue jays prefer to just pair up and don’t really socialize that much with other members of their own kind.
Hummingbirds as a group have never been observed to live in large groups. In fact, with the exception of their own mate, hummingbirds have a reputation for being extremely territorial and combative towards other members of their species. Until now that is.
Recently an ornithologist and birding guide in the Andes of Ecuador named Gustavo Cañas-Valle happened upon a cave where he was astonished to find dozens of hummingbirds of the species Oreotrochilus chimborazo both nesting and roosting together. The cave was located on the slopes of the Chimborazo volcano at an altitude of more than 4,000 meters, an extreme environment for any species.
“I thought, this looks like a colony,” Mr. Cañas-Valle recounted. “They were like bees.” In all 23 adult birds along with four chicks were found to be living in that cave. Mr. Cañas-Valle’s discovery has now been published in the journal Ornithology in November of 2024 and is the first ever documented example of hummingbirds living communally but it wasn’t the last. Since his initial find Cañas-Valle has discovered another six caves where specimens of O chimborazo are living in groups, all at extreme altitudes.
The possibility that it is the extreme conditions where they live that has caused O chimborazo to begin living in groups has been suggested by some evolutionary biologists but at the same time they caution not to read too much into the current evidence. As yet there is no evidence of any kind of social behavior where the hummingbirds benefit from their neighbors in such ways as raising the alarum when predators are near or informing the rest of the flock when a food source is discovered. In other words, it appears that at present the birds are just tolerating the other members of their species around them rather than working together as a group.
In either case more research is needed, a closer, more long-term study of this ‘hive’ behavior. Cañas-Valle is convinced that there are other caves with humming birds, perhaps of other species, and the ornithologist is already planning on conducting some surveys.
I look forward to seeing his results and I’ll be certain to let you know about them.