92 R.E.Johnson 1967 Journal April 28 Tilden Regional Park, Alameda Co., Calif. Scattered clouds, cool early growing warm. 6-10 AM. Zoo 107B field trip. This was the first Zoo 107 Bird Field Trip since March 3 and the change in species & activity is quite noticeable. Kinglets & Fox Sparrows are apparently gone. Black-headed Grosbeaks can be heard singing from all sides. Other new- arrivals (Warbling Vireo, Cowbird, Olive-sided Flycatcher, Bullick's Oriole, Western Flycatcher, Swainson's Thrush, & Wilson Warbler) are also singing but are not so conspicuously present as the Grosbeaks. A pair of bush-tits were observed building a nest. Also a Steller Jay nest was located in a Eucalyptus tree. Species observed: x Bush-Tit Robin x Black-headed Grosbeak x Warbling Vireo Scrub Jay Steller Jay - nest 30 ft up in Eucalyptus tree Cowbird (Brown-headed) American Goldfinch Mourning Dove Bullock Oriole Wren-tit Chestnut-backed Chickadee Calif. Gull - Flock overhead Bewick Wren Song Sparrow