Tuulligjuaq • Common Loon

The common loon is distinguished from the black-throated loon (G. arctica) and the red-throated loon (G. stellata) mainly by its larger size. It usually has a steeper forehead and a bulging forecrown, somewhat similar to the black-throated loon. Its bill is heavier and the back is paler than its hindneck. It is more difficult to separate from the yellow-billed loon, but its breeding plumage has more white markings on the neck and the squares on its shoulders are usually smaller; the non-breeding plumage has darker neck-sides contrasting more sharply with pale areas and bill colour.

https://en.wikipedia.org/wiki/Common_loon

Main Photo Credit: Common Loon by Matthew, 2006. https://www.flickr.com/photos/98023696@N00/199468711. Licenced with CC BY-NC-ND 2.0, https://creativecommons.org/licenses/by-nc-nd/2.0.
Second Photo Credit: Common Loon flying across Canada-U.S. border by Andrew Reding, 2013. https://www.flickr.com/photos/11802018@N07/8614650702. Licenced with CC BY-NC-ND 2.0, https://creativecommons.org/licenses/by-nc-nd/2.0.