Two recent studies* are cited in evidence:
To find out, Wikelski piloted his plane in circles to observe a flock of 70 storks on sunny spring and summer days. Even when the storks couldn’t see or hear the mowing, he and his colleagues noted, they homed in on mowed fields upwind of them, as if drawn to the smell of the cut grass. To confirm the suspicion, the team sprayed cut-grass smell—a mix of three volatile chemicals—onto fields that hadn’t been mowed recently. The storks came flocking, the team reported on 18 June in Scientific Reports. The work “shows very clearly that these birds rely exclusively on their sense of smell to make foraging decisions,” Whittaker says.
Other bird species may also respond to “calls” from injured plants, recent evidence shows. Two European birds, the great tit and the blue tit, locate insects that are attacking pine trees by detecting the volatile chemicals the stressed trees release, ecologist Elina Mäntylä of the Biology Centre of the Czech Academy of Sciences and colleagues reported in the September 2020 issue of Ecology and Evolution.
All these results show bird olfaction “should not be ignored,” Mäntylä says. Driver adds that they might also point to a new form of natural pest control, in which farmers or foresters could treat threatened flora with chemicals that entice birds to come and gobble up invasive insects.
Other studies suggest olfaction might guide social interactions between birds.Elizabeth Pennisi, “Textbooks say most birds can’t smell. Scientists are proving them wrong” at Science (July 7, 2021)
So “It’s in the textbooks!” is right up there with “Trust the science!”?