Numerous aspects of the biology of Fork-tailed Flycatchers are poorly known. Promising research questions include:
1. Why do migrants of the nominate subspecies (savana) use two wintering areas in northern South America (Jahn et al. 2013)? Other recent studies on passerine migration have revealed extensive movements throughout winter, the causes of which are still poorly understood.
2. What types of movements do different populations/subspecies undertake and how did migration evolve across the species’ range? Fork-tailed Flycatcher populations vary from resident to partially migratory to completely migratory across the species’ extensive range. Comparisons of migratory strategies and related physiological, behavioral and morphological traits among these populations could lead to novel insights on the evolution of bird migration under different environmental conditions.
3. What is the functional purpose of the long tail? Research on the relationship between morphological traits (e.g., tail length) and behaviors such as rate of extra-pair fertilization in different Fork-tailed Flycatcher populations could yield valuable information on the evolution of morphological traits under different selection pressures.