Avian phenology and survival
Timing of avian lifecycle events such as migration, breeding, and molt are often structured around climatically-influenced food resources. Determining how birds adapt lifecycle events to climate change and subsequent shifts in food resources represents a central facet of my research. I use long-term bird monitoring data from California, Hawaii, Costa Rica and Brazil to measure changes in breeding and molting phenology, and survival relative to climate. I often rely on model species to disentangle the interactive effects of climate and habitat on survival, and identify putative climatic refugia.
Landscape & community ecology
The development of MacArthur and Wilson’s (1967) Theory of Island Biogeography (where species richness and turnover was estimated by island size and distance to the mainland) energized ornithologists who sought to use the island model to predict avian richness in mainland habitat “patches.” These efforts sometimes failed providing several insights regarding the structure of bird communities in fragmented and degraded Neotropical habitats. These insights include:
Permeability (ease of travel by birds) through human-dominated landscapes between habitat patches influences bird communities within patches. Because variation in permeability around fragments affects bird communities within those fragments, I study bird communities within human dominated landscapes and adjacent habitat patches.
Ecological guild (diet, foraging strategy, etc.) affects a species response to habitat degradation. This topic has been widely explored in the Neotropics. In collaboration with Biodiversity Initiative, I am addressing similar questions in Afrotropical systems.
Seasonal movements of birds have captured the imagination of naturalists for millennia. The advent of diminutive tracking devices ushered in an era of discovery where connectivity between breeding and wintering grounds are continually being revealed. I employ geolocators and other technologies to study long-distance migration as well as study short-distance and upslope migration to better understand post-breeding movements of temperate birds.
Our research documenting the interactive effects of climate and habitat on bird survival was featured on the cover of Oecologia.
Prothonotary Warbler with attached geolocator at a nest box in Baton Rouge, Louisiana. Photo by John Hartgerink.