September is a challenging time to go birding. The woods are filled with juveniles, and there are those warblers difficult to identify. In the sky, the identification game is not much easier, as seemingly indistinguishable hawks dot the horizon. It is also a time of transition, and for long last looks at those once vocal neo-tropical summer migrants, whose absence of song contributes to the challenge and demands keener observation from us.

Silent September really began on the second week of August when the summer chorus of bird song ran out of breath and mornings broke eerie quiet. Though quiet, the songbirds had not departed. In fact, they are still with us now. Secretive and unobtrusive, they remain hidden, feeding, and gaining strength for the journey south.

Along the shorelines, whether inland or on the tidal coast, the shorebirds begin to settle in during late summer. Birders turn their attention to them and follow the flow of the ever-changing seasonal cycle. While shorebirds continue to move across the region, wood warblers are accumulating, and although less conspicuous than they were in the spring, they are nevertheless a significant factor during any September birding excursion.

Notorious for the challenge they pose, wood warblers are really a conquerable quest. A test of skill, the difficulty in identification is thought to be a result of molting. However, this is really somewhat of a myth, as warblers actually begin molting immediately after breeding. Instead, it is actually the juveniles that create the fall warbler problem.

In fact, most of the adults have already passed through our region. Specifically, those juvenile warblers that create the most confusion are probably the pine, blackpoll, black and white, bay-breasted, yellow-rumped, and magnolia warblers. Pine warblers are often confused with the blackpoll and the bay-breasted. Female pines have a more uniform color and have gray wings with wing bars. The bay-breasted has dark legs and feet, while the blackpoll has lighter toes.

Blackpoll and black and white warblers are also easy to confuse. The black and white warbler has two streaks or stripes, one above the eye and one below it. The blackpoll has an empty white area below the eye, but it can be greenish-yellow during the molt. To further distinguish these little birds, watch their behavior. The black and white warbler creeps on the tree trunks in a manner similar to the nuthatches.

At first glance, the magnolia and yellow-rumped warblers look similar. Look at the wings; magnolias (males) have large white patches, but the yellow-rumped has thin wing bars. In juveniles, these differences are not always distinguishable, but sometimes the yellow crown of the yellow-rumped predominates. The yellow-rumped warbler has yellow patches on the head, wing, and rump.

Juvenile American redstarts are confusing, too. They often fool birders into thinking they have spotted something much rarer, as they lack the dark black and orange hues, giving an exotic look to these common warblers.

Our coastal location amplifies the September challenge, as many juvenile species tend to hug the shoreline on their first migration. This is especially true of hawks. Unfamiliar with using thermals the way adults do to ride effortlessly from escarpment to escarpment, immature hawks choose the safer route along the coast.

The September challenge is one best appreciated by knowing that we cannot blindly accept what the field guides show us. All birders soon realize that, like humans, no two individuals look exactly alike. Likewise, birds never look exactly like they are depicted in the guides — there are variations, and September birding presents us with the greatest of these.

Robert Tougias is a Colchester birding author. His book “Birder on Berry Lane” is now available. You can ask him questions at roberts90gtias@yahoo.com.