Palmer, R. R. and J. L. Koprowski. 2015. How do Neotropical pygmy squirrels (Sciurillus pusillus) use seasonally flooded forest in the Peruvian Amazon? Journal of Mammalogy DOI:10.1093/jmammal/gyv138.

Tree squirrels are important components of ecosystems but to understand their role, we must learn how squirrels select and use habitat. Tree squirrel species richness is highest in the tropics and, according to the International Union for Conservation of Nature, is also where the greatest number of data deficient species occurs. The Neotropical pygmy squirrel (Sciurillus pusillus) is one of these species. In 2009 and 2010, we conducted distance sampling to estimate population density, we measured vegetation variables to investigate forest characteristics that influence habitat selection at 3 different scales, and conducted observations to obtain knowledge about activity patterns and behavior of Neotropical pygmy squirrels in igapó forest in the Peruvian Amazon. Density of squirrels was 0.10 and 0.14 individuals/ha, respectively, for each year. Squirrel activity peaked at 0800h, individuals were found mainly in the canopy and never on the ground, and frequency of squirrel behaviors differed by time and story level. Squirrels mainly used high and low restinga and areas that had more trees that were ≥ 30 cm diameter at breast height (DBH)/ha compared to random areas in our site in igapó forest. Squirrels used trees that were larger in DBH, taller, and had a larger live crown compared to random trees. Neotropical pygmy squirrels are associated with features related to mature forests.