Following the many World Stamp Show issues, the USPS apparently ran out of stamps to release at major stamp shows. This will explain the August release of four Songbirds in Snow Stamps. The stamps picture the Golden-crowned Kinglet, the Cedar Waxwing, the Red-breasted Nuthatch, and the Northern Cardinal.
The Postal People tell us, “The sight of birds sitting on a snowy tree branch and the sound of their songs and calls bring joy in the depth of winter.”
Though many birds migrate to warmer climates before the snow falls, some hardy birds have ways to cope with the cold. Fluffing their feathers creates an insulating layer of air, and their winter plumage can contain up to 30 percent more feathers than in summer. Many birds are able to slow their metabolism, lower their body temperatures, or even reduce their heart rate to help them conserve energy.