Investigating behavioural innovation and animal culture in overcoming sudden environmental change

The invasive cane toad Rhinella marina in Australia has been detrimental to many native predators through lethal toxic ingestion. However, reports are emerging that some predators, such as Torresian crows (Corvus orru), can safely consume cane toads by avoiding the toxic glands. Crows potentially have some resistance to the toxin, where ingestion induces sickness but not mortality, allowing rapid learning to take place. They also live in social groups, where innovative behaviours can be shared among their conspecifics. However, the mechanisms and development of this prey behaviour are unknown, including the role of social
learning. The transference of information may be key in C.orru’s ability to
succeed in an environment invaded by toxic prey. Furthemore, we have no knowledge on shifts in population dynamics in C.orru as a result of the toad invasion.
I will investigate behaviours involved in crows safely consuming cane toads in a series of captive learning trials both ahead and behind the invasion front in Northern Australia. Trials will involve exposing individual crows to treatments of either native frogs or various cane toad treatments including intact toads, toads with paratoid (toxic) glands removed, or toads with glands removed but toxins added back in. Social learning will also be explored by replicating cognition experiments on naïve crows that observe their conspecifics exhibiting successful
behaviours. I will also establish C.orru population estimates before, during and after the cane toad invasion in towns where the invasion is expected to spread within the next year.
At the conclusion of my PhD, I expect to have (1) explored mechanisms of this innovative behaviour and determine if it is a result of pre-adaption or rapid learning, (2) Determine the role of social learning in this behavioural innovation and (3) Identify the real-time shifts in populations of C.orru as the toad invasion spreads.