Evolutionary Responses to Climate Change in a Long-Distance Migratory Songbird: The Scarlet Tanager

Overview

In the 21st century, as the climate changes rapidly, many species are left with the uncertainty that their evolutionary processes may not keep pace. Profound consequences will result from the human population’s heavy reliance on the environment, so it is vital to protect species. In this study, a migratory bird species known as the Scarlet Tanager’s (Piranga olivacea) vulnerability to climate change was assessed in terms of its breeding range and morphology. P. olivacea’s geographical dispersion was projected and analyzed using the Species Distribution Model “Maxent”. Locality data for models was obtained from the Global Biodiversity Information Facility (GBIF) from 2000-2020, and April-October in North America. The WorldClim database was used for environmental data to assess P. olivacea’s relationships with minimum and maximum temperature and precipitation, factors impacted by climate change. WorldClim’s future climate data (under RCP 8.5) until 2070 was used to evaluate the Tanager’s future vulnerability. Morphological data from LSU’s Museum of Natural Science was utilized to examine P.olivacea’s morphological evolutionary development. It was hypothesized that Piranga olivacea will attempt to shift its breeding range and morphologically adapt to changing climatic conditions, but ultimately the species’s ability to do so will prove limited. Yet, the findings suggest that minimum temperature is the largest limiting factor in P.olivacea’s breeding range, and thus P.olivacea has the potential to expand its range past historical northern limits as temperatures rise. Findings additionally suggest that P.olivacea may be selecting for blunter wings for travel through dense forest habitats, as well as decreasing its tail length to accommodate for longer migrational distances.