To whom it may concern.
A while back there was an article in Scientific American which described how dinosaurs became birds. At the time I wrote an essay for this blog which referred to that article and another older article.
I found the older article on the Scientific American website under the title “how Dinosaurs Shrank and Became Birds,” from Quanta Magazine , June 2015.
I should be noted that birds developed originally at a time when climate became colder, so some dinosaurs developed feathers and became smaller to protect against the colder weather. Others became bigger to also protect against the cold, but this trend worked against them in the longer run.