This California Towhee may be looking for a mate. Why else sing so persistently? Generally, towhees mate and pair up for a whole season, and may stay together for life. They nest in low trees like the coyote bush where this individual was performing.
An interesting trivia about them is that they like to nest in poison oak bushes. The irritant in the leaves doesn’t bother them at all, and they feed on the plentiful berries that the bush produces in spring. Not to worry, there is no PO in the park.