One of the under explored frontiers of birding around the world is an appreciation of those birds that are in plumages not illustrated in existing field guides. The majority of these are those briefly held juvenal plumages, which are generally poorly known. Field guide authors and illustrators may chose to ignore them because of space constraints, since they are usually relevant for only a small portion of the year. One thing is true, soon after each new breeding season arrives, the Bird ID Q&A forum sees a sharp spike in postings featuring oddball juvenile birds. Many of these are remarkably different than the adults. The appearance of juveniles is well known for some groups of birds, such as shorebirds (waders), gulls, terns, jaegers, etc., but for other groups that information is sorely lacking. Birdforum could be a great place for someone to begin to compile a list of images of birds in juvenal plumages. There have been some really good head scratchers from North America and Australia recently. I would urge photographers to try and archive these in the Birdforum gallery, for they are a great potential resource.
Chris
Chris