Posted by Matthew Kenne (209.163.4.175) on December 21, 2000 at 08:19:33:
If I'm understanding my Pyle Identification Guide correctly (and if not, please correct me), all the nightjars have whitish or buffy tips to the wing coverts until they molt them in the fall of their second year. Sibley shows juveniles of the Nighthawks without illustrating this, but does show it somewhat on the Whip-poor-will juv. Maybe this is more of an "in-hand" feature than a "field" mark?