Tactical deception reduces predation on birds’ eggs

Abstract

n the months leading up to the 1973Yom Kippur War, the Egyptianmilitary staged 40 maneuvers on ornear the Israeli border. Over time,the Israelis learned that Egyptian activitynear the border was not necessarilya threat to respond to, and they ultimatelylet their guard down, only to be surprisedone day when the tanks and troopscrossed the border as part of a coordinatedinvasion (1, 2). In PNAS, Price andBanks (3) show that by using analogoustactical deceptions that rely on teachinganimals not to expect to find food,conservation biologists might be able toreduce predation on vulnerable ground-nesting birds.Conservation biology is a crisis disci-pline that is often at war with forces thatpush species toward extinction. Indeed,a major problem that has resulted fromour systematic killing of carnivoresthroughout the world is that we havecreated disequilibria that let former preyprosper (4). When those prey includepotentially harmful predators, such as rats(Rattus sp.) or hedgehogs (Erinaceuseuropaeus), that may eat bird eggs andnestlings, ground-nesting birds may bethe ultimate losers in this trophic cascade(5, 6).Conservation interventions may includeattempting to kill all the predators, whichraises ethical issues and is often difficult toaccomplish. Nonlethal interventions in-clude captive breeding and reintroductionto recover populations. However, many ofthese interventions fail (7). Failures arecostly and mean that the population is notrescued or recovered. Thus, research toreduce failures and create new nonlethalmeans to recover vulnerable populationsis ultimately a boon to conservationand welfare.Conservation behavior is a subdisciplineof conservation biology that appliesfundamental insights from behavioralbiology to conservation (where the goal istypically to increase small populations)and management (where the goal istypically to decrease overabundant pop-ulations or reduce their deleteriouseffects) (8). Many conservation and man-agement problems can benefit frommechanistic insights into how animalsrespond to stimuli and learn aboutbiologically important events.Previous DeceptionsOrganisms produce smells, and theseunique scents may contain potentialinformation about species, sex, age,identity, and reproductive status.Importantly, both conspecifics andheterospecifics may use these scents tomake biologically informed decisions,and learning is often an importantmechanism in decision making. It isgenerally known that hunters try to at-tract predators with the scents of theirprey, trappers try to attract animals