Three days ago on April 20th, the post reported on the tactics used by sheep in maintaining optimum vigilance so as to avoid being eaten while eating. Ducks have similar problems when it comes to ending up as dinner. Zimmer et al of the U of Strasburg have just published their study on duck tactics (1). Tufted ducks, teals and mallards were all recruited to the program. It must be stressed that none ended up as that well-known French dish, Canard a l’Orange, (a recipe is given in reference 2).
The whole time budget for the ducks was recorded. That is the times that they allocated to watching, eating, preening and sleeping. This was for control groups, and groups that had a quiet period followed by a period of predation activity, followed by a period free of disturbance. As mentioned above none were actually eaten and predation was simulated by a fast moving model monster truck rushing at them like a fast moving terrestrial predator determined to dine on duck today. ( The truck was an E-Zilla FWD Hot-bodies™ for the nerdy who wish to check the results at their local duck pond.)
The groups of disturbed ducks, that is those who thought that the radio controlled truck had come to eat them, spent less time eating or preening. The fascinating result is that they did not spend more time keeping watch. So what did they do to balance the budget? They slept.
Sleeping may not seem to be the best strategy to avoid being eaten. However, ducks are light sleepers, and although they may not sleep with one eye open, they do frequently open one eye to take a peek and then it's back to sleep. This peek, sleep, peek cycle make it difficult to creep up on them. Perhaps this is why we invented shotguns?
- http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0018977
- http://www.foodnetwork.com/recipes/emeril-lagasse/classic-duck-a-lorange-recipe/index.html
