Feb 28, 2005 — Great Gray Owl invasions, also called "irruptions", happen about once every ten years. But this one is the largest on record. Brian Sullivan is the project leader of the website, ebird.org, at the Cornell University Lab of Ornithology. Birders have posted Great Gray sightings from Minnesota to Montreal. Sullivan says it was only a matter of time until one was spotted in New York. Great Grays are one of the largest owls in North America, and they have a mysterious air about them. They're also known as the "Great Gray Ghost" and the "Phantom of the North". Sullivan told David Sommerstein despite those monikers, they're active during the day as well as night.