If you were to study the Putah Creek in Yolo County, you'd discover a wealth of wildlife, says retired museum scientist Ron Cole. Cole trains students to use field biology techniques and equipment by sending them to the creek that borders the UC Davis main campus and flows through the middle of Russell Ranch, the campus's western agricultural research area. Putah Creek is home to more than a dozen mammals and between 70 and 90 species of birds, depending on the season. About 40 bird species nest near the creek while the remainder pass through on their northern and southern migrations. Over the years a number of surprises have padded down the creek. Although mountain lions are a rare visitor, during the early-'90s drought, the dry creek bed offered a "nice path for travel from Berryessa" for two of the big cats, Cole says. Just two springs ago, a trio of graduate students were boating when they spied a young black bear swimming in the creek near the campus landfill. "It was fully grown and looking for new territory," Cole explains. The bear apparently returned to the hills where there are fewer researchers. Here's a partial list of what Cole and his students have found or documented over the years along the creek in Yolo County: Mammals o Eight to 10 species of bats o Opossum o Raccoon o River otter o Beaver o Columbia blacktail deer o Mink o Black bear o Jack and cottontail rabbits o Gray and ground squirrels o Gophers and moles o Mountain lion Birds o Swainson's, red-tailed and red-shouldered hawks o White-tailed kite o Mallard o Canada goose o Snowy and great egrets o Great blue, black-crowned night and green herons o Nuttall's woodpecker o Great horned and barn owls o Black phoebe o Anna's hummingbird o Oak titmouse o House finch o Western scrub jay o American goldfinch o Yellow-billed magpie