BirthsData for Aotus azarae

Births and fates (presumed dispersal, confirmed dispersal, death, still in natal group, or unknown) of offspring born in each of 30 social groups of Azara’s owl monkeys (A. azarae) at the Owl Monkey Project study site in Formosa, Argentina between 1996 and 2021. We classified the absence of an individual from its natal group between 1997 and 2020 in one of three categories: presumed dispersal, confirmed dispersal, or dead. A “presumed dispersal” refers to an individual, 18 months or older, missing from its natal group that was not seen again outside of the natal group. We chose 18 months as the minimum age for a potential dispersal because this is the youngest age when an offspring in the study population has been confirmed to leave the natal group and survive independently. We use “confirmed dispersal” for an individual that, after leaving its natal group, we observed ranging solitarily, or living as an adult in a new group. We distinguish between presumed and confirmed dispersal because, while it is reasonable to presume that a missing offspring > 18 months has dispersed, it is still possible that some of them may be missing because they died while still in their natal groups. We classified an individual less than 18 months old as “dead” when missing from its natal group; those 18 months or older were considered “dead” when observers found the remains within the home range of the natal group.