Here’s a Yellow-rumped Warbler photographed at Prince Edward Island National Park. Most warblers migrate to Central or South America for the winter, but Yellow-rumps stay in the southern United States and northern Mexico. Migration decisions are usually based on food availability rather than cold weather. In this case, Yellow-rumped Warblers are able to digest the waxy berries of Bayberry, Juniper, Wax Myrtle, and others. That allows them to overwinter much farther north than other warblers.