I'm putting together a TX trip for next spring, the plan is to fly into San Antonio, run down to the lower coast (Botteri's sparrow), then up the Rio Grande Valley, back north to the Edwards plateau to look for Golden-Cheeked warblers and Black-Capped vireos, and out to Big bend for the Colima, and whatever other neat stuff I can see. (I've already had a winter TX trip so I've seen a bunch of the specialties.) What I'm looking for are recommendations on timing to maximize my chances of seeing the species mentioned. Any assistance with this would be greatly appreciated. Thanks...