I had forgotten how stunning the vista is at the Santa Margarita bluffs. This access is separate from the old river access and is a short if potentially steep hike from a caliche road (the steep bit can be skirted through some cenizo and thorny brush with caution). I was last in this area in the early 80's (!). This is a private ranch with an admission fee and requires pre-arrangement for a visit; contact me for information until I get an email address to share. The view is spectacular; I'm not sure this iPhone panorama does it justice.
Looking upstream - north - the spillway at Falcon Dam is in the distance, and Salineno and Chapeno are in between. The riparian corridor is intact on both sides of the river, and easily birded with a good scope.
I didn't see any Red-billed Pigeon, but this vista is perfect for watching for them - and seeing the White-winged Doves that sometimes fool unwary birders that only see them from below. Muscovy Duck fly low to the water, so you'd have to concentrate on the river to catch a view of them before they are past you.