Ex-situ conservation and breeding management of Southern cassowaries (Casuarius casuarius)

Sweetman, Zoë Rebecca (2025) Ex-situ conservation and breeding management of Southern cassowaries (Casuarius casuarius). Masters by Research thesis (MSc), Manchester Metropolitan University.

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Abstract

Despite a long captive history, breeding success of Southern cassowaries (Casuarius casuarius) in zoological organisations has been sporadic. Very little is known about their courtship and breeding behaviours, in particularly the part that vocalisations play in courtship display. In addition, as birds can be aggressive towards conspecifics, bringing birds together for the purpose of breeding (mixing) must be timed correctly. Therefore, understanding courtship and reproductive biology in this species is essential to improving management and breeding in zoos. This study examined three aspects of courtship and breeding in Southern cassowaries – courtship precursor behaviour, vocalisations, and hormonal profiles – across multiple birds and institutions. Instances of courtship behaviours and vocalisations were extracted from video footage and audio recordings, respectively. Hormone levels were monitored through non-invasive faecal sampling. I found that both precursor behaviours and vocalisations increased prior to mixing and varied seasonally, increasing in the spring and summer months before dropping in the winter. Rates at which both behaviours and vocalisations occurred differed widely between zoological organisations. Hormone levels showed seasonal changes, increasing between April and October and dropping again in the winter. However, changes in relation to mixing were not observed. There was no clear relationship between behaviour changes and hormone concentrations in the birds studied. Although mixes were successful, with no separation due to aggression, fertile eggs were not produced during the study period. Despite this, observations of Southern cassowary behaviours and vocalisations could still be helpful in determining the correct time for mixing as, anecdotally, when used to time mixes, aggression among conspecifics was limited. Hormone profiling of these birds may also be beneficial as a husbandry tool for identifying potential reproductive problems. Implementing monitoring programmes could help to improve reproductive success and management of this complex and potentially dangerous species in captivity.