Research

Ecosystem (dis)services provided by wild birds on organic farms

American goldfinch_full belly

bird box at say hay

Recently, birds and other wildlife have been blame for outbreaks of food borne disease in humans. In response, many growers in the United States have been pressured to clear natural vegetation from their farms. However, the costs and benefits of birds associated with natural vegetation on farms are largely uncertain. I am working with Bill Snyder and Jeb Owen at Washington State University to assess the net impacts of birds on organic farms. We are collecting poop samples across the western US to analyze diet and pathogen prevalence in wild birds at 40 organic vegetable farms.

 

Causes of decline in endangered Tasmanian songbirds

Shot_By_Angi_Pardalotes-063

forty-spotted pardalote in net Forty-spotted pardalotes are endangered habitat specialists native to Tasmanian, Australia. Recently, I spent 3 field seasons climbing to their nests to monitor their breeding success. With a crews of intrepid field assistants, I camera-trapped for predators, measured aggression for nest hollows with a common competitor, and eventually discovered that a tiny fly parasite was the real problem for forty-spotted pardalotes. Passeromyia longicornis, a native fly parasite, was killing 81% of nestlings, and is now the largest known source of mortality for the species. But  the birds also have lots of other problems including extreme diet specialization on a sugary sap-like excretion produced by white gum trees (Case and Edworthy 2016), and loss of this critical habitat.

 

Long-term survival and characteristics of tree cavities used by bird and mammal communities

mountain bluebirds and tree cavity tree cavity survival figure

Tree cavities are a shared resource for more than 30 species of birds and mammals in interior BC. During my MSc with Kathy Martin at UBC, I studied factors influencing persistence of tree cavities in both mature forest and forests harvested with retention of aspen trees (the primary cavity tree). I also studied changes in tree cavity characteristics over time, which affect their likelihood of use by species including bluebirds, woodpeckers, ducks, and squirrels.