If you are looking for wildlife-related experience, there are many wildlife-related volunteer opportunities in the Sacramento area, like CDFW, USGS, USWFS, etc. Many employees at CDFW are UCD alumni and would welcome volunteers. I volunteered briefly at the CDFW regional headquarter in Rancho Cordova last year. There are many experts working in the office and they frequently offer wildlife survey/study trips and classes for you to attend. My supervisor also offered to write me recommendation letters in the future when I left. I think this experience and recommendation from experts in the field will boost your chance of getting into a wildlife biology program. Wish you all the best!