In conversations about wild deer in Australia we are routinely confronted with a number of myths.

Most of them are well worn and whilst bemusing, are no surprise to hear. 

Every once in a while we get one which is novel. Today’s ‘myth’, from our National Broadcaster is certainly that.

ABC Radio Adelaide are faithfully reporting about “Feral deer ‘cultivating’ olive trees in Adelaide Hills as the pest plant strangles vegetation”, the report goes on to air claims by 'environmentalist' Peter Bird that fallow deer are:

Eating olives

Scratching out impressions in the ground

Regurgitating the olive seeds into the impressions

Covering them back up

Waiting for the rain to water them in

Defecating on top of them to fertilise them.

"So they're harvesting the seeds, they're pre-treating them, covering them up, watering and fertilising them. They tell us that humans started cultivating olives about 6,000 years ago, but I suspect the fallow deer have been doing it a lot longer than that."

It all sounds a little bit far-fetched…that’s because it is.

Fallow deer are extraordinary and adaptable animals, but they haven’t quite evolved from being wild, mixed feeders to forming agrarian societies.

A search of 1,430 scientific articles could find no research or literature to support Mr Bird’s extraordinary claim. That is despite both fallow deer and olives both being endemic to the same parts of the world.

What the science did show us is that, in Israel, where olive trees (Olea europaea) are both abundant and culturally significant, there was no evidence of fallow deer playing a role in the dispersal of olive seeds.

A 2016 study, looking specifically at the role of re-introduced fallow deer in endozoochory (the dispersal of seeds, spores or organic material by an animal) found limited evidence of the deer being a potential vector for thirty-six plant species – olives weren’t one of them...they didn’t rate a mention in an exhaustive, extensively referenced study.

It’s not terribly concerning that individuals come up with weird and wonderful theories such as these, in fact it can be quite amusing.

It is a worry however that they get airtime and uncritical reporting on the public broadcaster.

Not a great use of our 19 cents a day.

Reference:

Endozoochory by the Persian fallow deer (Dama mesopotamica) reintroduced in Israel: species richness and germination success.

Royi Zidon, Hagar Leschner, Uzi Motro and David Saltz