Sometimes it is tough to see more than a silhouette of a bird you are trying to identify. When you are looking into a bright sky, the light is often coming from the same direction as you are looking making the bird in question backlit. Even light colored or brightly colored birds can look pretty black. Other times in low light it can be difficult to see much more than a silhouette. For these reasons, and because learning the silhouettes of common birds in your area can help you quickly come to a small list of possible species when you are trying to identify a bird, many field guides and bird identification lessons start with showing the value of learning to identify silhouettes.
Today I was on a walk about an hour before sunset on an overcast day with poor light and not many birds. Many of the birds I did see were silhouetted against a gray sky and got me to remembering the silhouette page on the old Golden Guide and in the Peterson guide books I studied when I was just starting as a birder. Here are a couple of photos I took today.
Admittedly the American crow is a black bird without many clues to identification except for size, shape, voice and behavior, but this silhouette makes the ID instinctual to experienced birders.
This Northern flicker has a very distinctive silhouette even when seen poorly and when little color is seen, the ID is usually easy based on the silhouette shape.
Here is a good online resource to silhouettes on the Cornell University site. http://www.birdsleuth.org/teaching-bird-id/
Good birding.
