Hyperdispersal is the long-distance movement of individuals after release, also referred to as homing behaviour, panic dispersal, failure to settle and extreme post release movement. Hyperdispersal appears to be common in a range of taxa but is rarely acknowledged as a major factor in translocation failure. We review reported incidences of hyperdispersal in the global literature and compare rates of hyperdispersal among taxa, population demographics, release cohorts, and the success of mitigation techniques. From 151 conservation translocations where animal movements were detailed, we confirmed hyperdispersal in 52.1% of programs. We found numerous definitions used to describe significant post release movement of individuals, with most describing situations where an individual moves away from the translocation site such that it becomes isolated from the rest of the release cohort and is unlikely to contribute to population establishment.

The prevalence of hyperdispersal (percentage of studies) was relatively consistent across taxa (42.9–60%) suggesting that the issue is common and widespread. The prevalence of hyperdispersal is likely significantly underestimated as collar failure is commonly blamed when animals are unable to be located after release. For example, 77% of bird translocations reported incidences where birds could not be located after release but only 44% of bird studies reported hyperdispersal. The incidence (percentage of individuals in a cohort) of hyperdispersal was higher in eutherian mammals (20.2%) than birds, reptiles and marsupials (10.4%, 15.7%, and 10.3%, respectively). However, incidence was highly variable between species even within taxa with some recording hyperdispersal rates of 100%. No significant trends were observed for sex, source population or translocation type, but there were non-significant trends for sex and presence of conspecifics. A range of mitigation techniques were used by practitioners to try and reduce hyperdispersal including temporary confinement, supplementation of resources, and releasing animals in social groups. We outlined the success of each method and found only half of studies testing mitigation techniques found them useful. We suggest that hyperdispersal is an underacknowledged but significant welfare, economic, and conservation issue in translocations and requires specific experimental strategies to understand and address it.