Assessment of releases of translocated and rehabilitated Yucatán black howler monkeys (Alouatta pigra) in Belize to determine factors influencing survivorship

Outcomes for an arboreal folivore after rehabilitation and implications for management

Wildlife rehabilitation is a critical part of animal welfare that contributes to species conservation. Despite the resources that go into rehabilitation, how animals fare after release from care is unknown. This is particularly true for cryptic arboreal species where specialist diets in care and low detectability in the wild present challenges for both care and post-release monitoring. We evaluated post-release outcomes for koalas and assessed if koalas were fed appropriately while in care. We monitored 36 koalas that had experienced one of three categories of medical intervention (none, minor, major) during rehabilitation. We examined the drivers of (i) koala survival and (ii) movements post-release, and (iii) evaluated variation between the species of browse fed in care versus browse selected by koalas in-situ. Overall, the post release survival rate of koalas was 58.5%, with only koalas that received medical intervention experiencing mortality. A critical threshold for mortality occurred at two weeks post-release and mortality was related to the measurable indicators of low body condition and poor climbing ability at time of release. In the month following their release, animals translocated furthest from their capture point moved the furthest. There was poor overlap between the tree species that koalas were fed in care and those they utilized post-release. We provide recommendations to address critical gaps in rehabilitation practices, as well as priorities for monitoring animals post-release to improve outcomes for arboreal folivores.

Births during 7 years after the translocation of a pair of black-and-gold howler monkeys (Alouatta caraya) to a forest fragment in southeast Brazil

Fecundity in female primates is influenced by the nutritional condition. If when translocated howler monkeys exhibit the same breeding patterns as non-translocated members of the same genus, it is an indication that the translocated monkeys have become well adapted to their release site and that they are likely in good nutritional condition. The objective of this study was therefore to investigate this pattern by recording copulations (over 5 years) and births (over 7 years) after the translocation of a pair of black-and-gold howler monkeys (Alouatta caraya) and to evaluate their gestation period, seasonality of births, and intervals between births. The pair was released in November 2009 on the campus of the University of São Paulo in Ribeirão Preto, São Paulo State, Brazil. Data on copulations were collected from January 2010 to March 2011 and from January 2012 to December 2014. Births were collected from January 2010 to December 2016. During the 5-year observation period, 25 copulations were recorded. Seven births were recorded over a period of 7 years, which included reproduction of the offspring of the translocated pair. Births occurred in the dry season between April and August. The interval between births was approximately 1 year. Our data provide insight into the reproduction of howler monkeys that have been translocated to a new habitat. Translocation can provide a valuable approach for rescuing or restoring Alouatta, whose populations have been detrimentally impacted by long-term habitat fragmentation.