This video from the USA is called Carolina Chickadee Sound.
From All About Birds blog in the USA:
Warming Temperatures Are Pushing Two Chickadee Species—and Their Hybrids—Northward
By victoria on Thursday, March 6th, 2014
The zone of overlap between two popular, closely related backyard birds is moving northward at a rate that matches warming winter temperatures, according to a study by researchers from the Cornell Lab of Ornithology, Villanova University, and Cornell University. The research was published in Current Biology on Thursday, March 6, 2014.
In a narrow strip that runs across the eastern U.S., Carolina Chickadees from the south meet and interbreed with Black-capped Chickadees from the north. The new study finds that this hybrid zone has moved northward at a rate of 0.7 mile per year over the last decade. That’s fast enough that the researchers had to add an extra study site partway through their project in order to keep up.
“A lot of the time climate change doesn’t really seem tangible,” said lead author Scott Taylor, a postdoctoral researcher at the Cornell Lab of Ornithology. “But here are these common little backyard birds we all grew up with, and we’re seeing them moving northward on relatively short time scales.”
This video from the USA is about black-capped chickadees.