EAGER: Climatic drivers of demography and reproductive behavior of tropical birds

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Weather has a large impact on where animals are found and how they live. We know a lot about how seasonal patterns of temperature (winter vs. summer) impact the animals around us, but we rarely consider how seasonal patterns of rainfall might impact animals in considerably different ways. Such impacts are especially likely near the equator, where the temperature is always high and seasons can swing dramatically between "wet" and "dry". This project will test how a tropical bird manages to thrive in an area that experiences periods of extremely high rainfall. This type of study is important for helping us understand how changing climate may impact animals, especially in places like the tropics that contain a large number of species that are found nowhere else. Results of this research have the potential to change how we view the role of climate in the lives of tropical organisms. One of the classic paradigms in tropical ecology is that year-round warmth and humidity frees organisms from climatic stressors and constraints, releasing them from energetic limitations and heightening the importance of biological interactions in shaping life history and behavior. This project is intellectually risky because it challenges this deeply entrenched view. The investigator proposes that precipitation extremes limit fitness and tests the hypothesis that precipitation-fitness relationships are unimodal. The work builds upon more than a decade of studies on a small, tropical, frugivorous, lek-breeding bird -- the White-ruffed Manakin (Corapipo altera) -- in Central American montane forests. The investigator will elucidate responses of manakins to variation in long-term mean precipitation regimes and short-term rainfall events across populations spanning moderately wet to extremely wet forests on both the Pacific and Caribbean slopes of Costa Rica. Mechanistic links will be sought between high rainfall and manakin survival, body condition, and reproduction. Additionally, previously-documented reproductive behavior and lek attributes will be contrasted with data from two new focal populations on the Caribbean slope, testing proposed climatic constraints on sexually-selected behavior at leks. Two PhD students and four undergraduate students will be mentored in research and the team will produce educational materials for use in public schools.