Jahn, A. E. | Search bioRxiv

bioRxiv2024

En route activity of Chilean Elaenia, a long-distance migratory bird in South America

The logistics of measuring activities that occur at fine temporal scales, such as short stopovers that last a few hours, has proven very challenging when studying small migratory birds. Here, we deployed multi-loggers equipped with an accelerometer and thermometer on Chilean Elaenia (Elaenia chilensis) to evaluate their activity patterns while they undertook their annual migration from their Patagonian breeding grounds to non-breeding zones in Brazil. Results show that elaenias can fly at altitudes of >1500 masl and migrate nocturnally, providing the first evidence of this behavior in a Neotropical austral migrant. Although most migration flights lasted less than 8 h, one individual flew non-stop for more than 28 h. Overall activity patterns (e.g., flight and stopover duration) were not substantially different between pre- and post-breeding migration. This technology offers a window into the migratory behavior of small birds that migrate within the Neotropics at a finer temporal scale than previously possible.

ecology↗

bioRxiv2023

Movement-related drivers of exposure to West Nile virus by American robins (Turdus migratorius)

The ecological processes that determine how individual animals become hosts to zoonotic pathogens is a topic of rapidly growing interest. However, how such exposure is mediated by context (e.g., season, location), host behavior (e.g., migration distance) and host demographics is generally poorly understood. We evaluated seasonal exposure to West Nile Virus of American robins sampled in Indiana and compared our results to those of previous studies. Because robins that breed in Indiana are partial migrants (i.e., only a portion of the population migrates), we evaluated their probability of exposure to WNV as a function of whether they migrated or not and of their movement distance. We also tagged a subset of breeding robins with tracking devices to evaluate their potential to disperse the virus between Indiana and other regions of the continent. We found that robins that breed in Indiana are exposed to WNV at a higher rate than that detected in previous studies, but found no correlation between robin exposure and whether a robin migrated or not, nor with migration distance, season, sex, and breeding latitude (for robins overwintering in Indiana). Our tracking data indicate that robins that breed in Indiana migrate several hundred miles to overwinter in the southeastern US. The mean duration of their return to Indiana in spring is 10.3 days, which is less than the maximum infectious period found for robins in previous studies, suggesting that they have the capacity to move WNV long distances in spring. However, we still know little about the physiological capacity of robins to migrate while being infectious, which could inhibit the dispersal of the virus through robin migration. Future research on the physiological, ecological and behavioral factors mediating the exposure of birds to WNV will lend insight into the role that robins and other birds play in the transmission ecology of the virus.

ecology↗

bioRxiv2022

Novel Rickettsia spp. in two common overwintering North American passerines

American robins and dark-eyed juncos migrate across North America, but their contributions to arthropod-borne disease remain poorly characterized. We identified novel Rickettsia spp. in one wintering migrant per bird species related to bellii, transitional, and spotted fever group rickettsiae and suggest spring migration could disperse these pathogens hundreds-to-thousands of kilometers.

ecology↗