The most recent revisions to the migratory bird act can be found online; my favorite part, and the most useful, is the list of species NOT covered by the act. These are the birds I find, use, and adore (along with game birds, and pets). If you decide to scroll to the bottom (or actually read the notes, I don’t know what kind of sicko you are, after all) you will find quite an extensive list, many of which you will also find represented in my artworks.
I collect a lot at wildlife facilities, and the feathers and bone I collect there are from birds that do not inhabit north america or the US.
As for bones, skulls, and incidentals of mammals and reptiles/amphibians- I don’t use anything on the CITES list, I either purchase or obtain my pieces legally; sometimes through roadkill salvage where that’s permitted, by finding natural remains, or by beach combing.
It’s not hard to find beautiful natural objects. Simply taking a walk away from other people is often enough. I use plant materials, as well, and collect those in the same way. There’s something deeply fulfilling about walking, looking, and finding. I will use anything I find in some way, just about- whether for my private collection or for artwork.
I do have an artist’s statement hanging wherever these sorts of works are shown. If you’re at the gallery it’ll be right by the first piece you see when you walk in. I will probably post it up here this time too.