This weekend marks the annual Great Backyard Bird Count across Canada.

Running from February 14th to the 17th, volunteers count the birds they see for at least a 15 minute period on one or more days, and enter their checklists on a website set up for the event.

Bird populations have seen an alarming decline across Canada and around the world. North America lost nearly 3-billion birds over a 50 year period according to a recent study.

Staff with the Nature Conservancy of Canada will be participating in the bird count in various parts of the country. Each volunteer or group choses a nearby location to count birds.

Volunteers can count birds outdoors, or through a window.