This article is from the Birds FAQ, by Lanny Chambers with numerous contributions by others.
Quite likely. Post as complete a description of the bird as you can.
Give the location in which you found the bird, and describe the habitat.
Also describe its behavior and any vocalizations you heard.
Obviously, describing the bird will be easier if you took notes while
observing it, an excellent habit to be in. Most field guides include
a "map of a bird": a schematic drawing of a bird with all the parts of
its anatomy labeled. This picture will help you note the details of an
unknown bird systematically.
Here's a short list of questions which might help you get started on
a "What is this bird" post.
+ Was it the size of a sparrow? Or a robin? Or a crow? Or a hawk?
+ Did it have a long or a short beak? What shape and color was it?
+ What color was its head? Did it have an eyebrow or a ring around its
+ What color was its back?
+ What color were its wings? Did you notice any horizontal stripes on
+ Did it have long or short legs? What color?
+ Was its tail long, like a mockingbird's? What color?
+ Where did you see the bird--not just where geographically, but what
kind of setting: forest, beach, field, parking lot...? What time of
day was it?
+ What was the bird doing? Did it make any sounds?