April 3, 2013 —
Spring is here, even if it seems late for a lot of people. Many animals are getting ready for the warm weather to come. Migration and breeding activities are at the top of the list for many birds, and newly born young of various mammal species will shortly make their appearance.
For many species of animals, their appearance changes from winter to summer. For many mammals, such as the whitetail deer, this change is a practical adaptation for the warm summer months. Deer molt their winter coat and a thinner, redder-hued summer coat takes its place. Other mammals go through similar molts, but a color or other visible change is usually not so obvious.
For some birds, the approach of the breeding season means a molt into vibrant plumage, likely an adaptation to signal and attract prospective mates. For someone unfamiliar with a given bird’s breeding vs. non-breeding plumage, the same bird may appear as two entirely different species. The males (usually with brighter plumage than the females) of some species may exhibit more of a difference between winter and summer.
Many of the birds in our region that exhibit this trait are migratory, and we never see their full breeding plumage because they have moved on to parts north by breeding season. Some species are here year round, and seasonal plumage variations can be readily observed. A frequent feeder visitor, the American goldfinch, is a favorite to observe winter vs. summer plumage. Whether for protection or for show, Mother Nature makes sure her charges are dressed for the occasion.