Real Science on Old Hill

by Kate Howard

A very very early morning spent counting birds on Old Hill

One of the leading causes of declines in wildlife populations is habitat loss, and land conversion to agriculture is a large source of such loss. If it can be shown that wildlife species provide benefits to farmers, a concept known as ecosystem services, conservation can potentially be a boon for agricultural practices. For my senior thesis as an undergraduate at Humboldt State University, I’m currently looking into the potential of songbirds to offer California wine-grape growers ecosystem services in the form of pest removal. I have been running experiments this summer in Sonoma (on Old Hill Ranch) and Mendocino counties to assess whether songbird predation of larvae (caterpillars) in vineyards is highest closer to the edge of vineyards where they are bordered by natural oak habitat. To do this, I’m placing mealworms pinned to cardboard squares staked to the ground along straight lines through vine rows perpendicular to natural habitat. This essentially simulates a “pest outbreak” of larvae, allowing me to measure predation rates as removal of the mealworms. I came up with the idea based on a study by Julie Jedlicka from UC Santa Cruz, where they deployed bluebird nest boxes and measured the birds’ predation rates. The new spin here is the connection to habitat instead of nest boxes. It turns out, where there are bluebirds, there’s larvae predation! I’m still in the data collection phase of my work, so there is analysis yet to be done, but we have successfully captured video footage of western bluebirds munching on our deployed mealworms in at least one vineyard. All vineyards so far have shown at least some level of predation. As most farmers intuitively know, the more biodiversity the land supports, the better!