| While ;Nest mortality rates on restoration and mature forest sites were comparable, indicating that restoration sites are functioning as well as forest sites as breeding habitat, in terms of nest predation. Results for the Spotted Towhee (Pipilo maculatus) indicate that nest predation, in addition to nest parasitism, by the Brown-headed Cowbird (Molothrus ater) may be a critical limiting factor for this population. Results for the Black-headed Grosbeak (Pheucticus melanocephalus) indicate that flood timing influences nest predation, as nest predation rates are lower when the median flood date is closer to the onset of nesting, suggesting that spring floods regulate nest predator populations. This study underscores the importance of large-scale horticultural habitat restoration, combined with naturalization of the river flow regime and reconnection of the river with the floodplain to songbird populations in California's Central Valley. |
