Emigration orientation of juvenile pond-breeding amphibians in western Massachusetts

We studied the emigration of juvenile age-class individuals of four species of pond-breeding amphibians at 14 seasonal ponds over four consecutive years in western Massachusetts. Emigration orientation of each species was non-uniform for the majority of pond-years examined. While orientation was decidedly non-uniform in most individual pond-years, combining data from successive years led to a more uniform distribution for each of the study species, although in no case did it actually become statistically uniform. Additionally, while the exact orientation of each species at each pond differed among years in almost all cases, there were some directions with consistently greater than or less than expected use across years for all ponds. Similarly, despite overall differences in orientation of individuals among ponds for a particular species, or among species at a particular pond, there were some consistent directional biases (positive and negative) across ponds and across species. Overall, our results suggest that while there are some consistent patterns in emigration among years, species, and ponds, variability in orientation over time and space is the norm. Thus, there is a need to acquire data over several years and several ponds before reaching conclusions regarding orientation patterns and making informed conservation decisions.