What is THAT bird? This is the annual cry of frustration from many a birder during fall migration, when spring’s flashiest male birds are sporting more muted attire. These birds have had a very busy spring and summer finding a mate, defending their territory and raising chicks – all of which requires an enormous amount of energy singing and producing showy feathers to attract a mate. Now with those tasks behind them, they have some time to be more practical. They aren’t calling as much – often they are silent. No need to sing and make your presence known to a predator as your territory and family are no longer at stake. And no need to have those flashy feathers to find a mate, so molting those for a less obvious outfit can be a very practical life saving technique.
But what makes the male birds less of a target by being more subtly colored, also makes them harder to identify as they may look much different in the fall. The folks at Princeton University Press come to the rescue with a downloadable page of images of all warblers found in the eastern US in their fall plumage. Yes, all on one page, so you can compare each one, study the fall markings of these birds, and even laminate it to use in the field. To download this pdf and quit trying to guess which bird is which, click here. If the guide just doesn’t do the trick, they also have a book with detailed info on warbler identification — The Warbler Guide written by Tom Stephenson & Scott Whittle.