Abstract
Previous studies have shown Olive-sided Flycatchers (Contopus cooperi) to be associated with burned forest, which suggests that wildfire is beneficial to the species. To examine that more closely, we studied the short-term effects (first two years after disturbance) of moderate- to high-severity wildfire on Olive-sided Flycatchers breeding in northwestern California. During summers of 2000 and 2001, we investigated distribution of and compared the relative nest loss, foraging rates, and aerial arthropod biomass at Olive-sided Flycatcher territories in burned and adjacent unburned forest. The probability of postfire site occupancy was best predicted by the presence of pre-existing forest edges (odds ratio = 8:1). Probability of relative nest loss was much higher in the presence of fire (odds ratio = 9:1). Adult female peak foraging rates were nearly twice as high in unburned (2000 = 2.1 attacks min−1, 2001 = 2.5) as in burned (2000 = 1.0, 2001 = 1.5) territories, and relative aerial arthropod biomass was nearly twice as high in unburned (2000 = 1,909 mg 2 m−2 40 days−1, 2001 = 3,200) as in burned (2000 = 1,105, 2001 = 1,751) territories. Although Olive-sided Flycatchers occupied recently burned areas, fire had apparent negative effects on reproduction. Poor reproduction appeared to be partially related to reduced food availability in recently burned areas. Our data suggest a need for detailed investigations of the relationship between Olive-sided Flycatchers and wildfire as postfire forest regeneration progresses.
Short-Term Effects of Moderate- to High-Severity Wildfire on a Disturbance-Dependent Flycatcher in Northwest California
