Changes in gut microbiota of migratory passerines during stopover after crossing an ecological barrier

Abstract

ABSTRACT The gut microbiota is a large and diverse community of microorganisms that provides many beneficial functions to the animal host; however, any change in the host's external or internal environment can affect microbiota composition. Migratory passerines arriving at stopover sites show highly variable microbiotas, which is likely reflective of the widely different habitats and foods utilized by migrants prior to arrival. If the previous environmental conditions led to the observed initial variability, then the microbiotas of birds should become more similar through stopover when migrants are in the same habitat and able to utilize similar resources. During spring 2014, migratory Swainson's Thrush (Catharus ustulatus), Wood Thrush (Hylocichla mustelina), and Gray Catbird (Dumetella carolinensis) were captured at a site in southwest Louisiana, USA, (1) upon arrival after crossing the Gulf of Mexico and (2) ≥1 day later during stopover. Fecal samples were collected and the microbial communities in the...