Hightlights:
Cassin's Vireo (1) - seen on both 4/13 and 14 between 10-11AM feeding and calling from trees surrounding the nectar garden (pics http://www.flickr.com/photos/jerryting/7078103435/).
Yellow Warbler (1) - seen on 4/13 at same spot as above.
Orange-crowned Warbler - seen on both 13th and 14th at the above location.
Hammond's Flycatcher (1) - seen at plum trees behind the nectar garden.
Ash-throated Flycatcher (3) - all seen on 13th at 3 different spots. 1 seen at Muskrat Trail (hiiside - east of the visitor center parking lot with steps leads to the hill top). The 2nd one was seen at Quail Trail hill side right next to the big eucalyptus tree. The 3rd one was seen flycatching and perching on trees surrounding the big pine tree at Hoot Hollow (pic http://www.flickr.com/photos/jerryting/7078761929/in/photostream).
lack-throated Gray Warbler (2)- 1 male seen on 13th around noon in California Buckeye tree beside the picnic area at Hoot Hollow. Today (14th) saw another male at the Bay Oak Tree right next to the side door (with nest boxes) of the Nectar Garden around 10:30AM. It then flew and perched on the tree right beside the Visitor Center gate and even went down to the funtain to drink. Based on the images that I took (pics http://www.flickr.com/photos/jerryting/6932089198/in/photostream the last one was taken on 13th at Hoot Hollow) it seems to me these are 2 different birds.
White-faced Ibis - 9 of them and some in iridescent purple plumage with white face seen at the flooded area southwest of the Kiosk on 13th afternoon around 5PM.

Other mentionables by areas:
Main Marsh in front of the Visitor Center parking lot -
-Cliff/Barn/Tree/Northern Rough-winged/Violet-green Swallow, Common Moorhen, Great-tailed Grachle.
Nectar Garden and surrounding trees - Wilson's Warbler,Bullock's Oriole, Allen's Hummingbird, (possible) Swainson's Thrush, Wrabling Vireo.
Hoot Hollow and Quail Trail - Great Horned Owl (occupied the nest on the big pine tree again this year), Red-shouldered Hawk, Common Raven, Pacific-slope Flycatcher, Western Kingbird (several).
Flooded Areas around the Kisok - Willet, Greater/Lesser Yellowlegs, Cinnamon Teal, Dunlin, Long-billed Dowitcher, American Pipit.

Happy Birding,

Jerry Ting
Fremont