We have long been aware that hummingbirds have great eyesight and hearing.  However, biologists have unable to demonstrate that hummingbirds could smell.  However, recent studies conducted by researchers at the University of California Riverside have revealed for the first time that hummingbirds can smell insects that pose a danger to them while they are visiting flowers bearing nectar.  The findings also suggest that this ability helps them avoid danger while feeding.

       According to Erin Wilson Rankin, associate entomology professor and coauthor author of the paper that was published in   the journal Behavioral Ecology and Sociobiology, “This is pretty exciting, as it is the first clear demonstration of hummingbirds using their sense of smell alone to make foraging decisions and avoid contact with potentially dangerous insects at a flower or feeder.”

       The experiment was deceptively simple.  They provided more than 100 hummingbirds the option of feeding at two feeders.  One feeder contained sugar water and another filled with sugar water and additives that indicated that an insect was present.  One additive was formic acid which is produced by some Formica ants.  This chemical is known to be harmful to humans and mammals alike. The other was an ant attraction chemical. Another chemical tested was a chemical left behind when a European honeybee visits flowers. 

       The hummingbirds seemed oblivious to the honeybee-generated chemical.  However, the birds avoided food laced with both of the ant-based chemicals.

       Since all of the feeders were identical, the only way that the birds could differentiate between the feeders was through their sense of smell.

       It seems like every few years we learn something new and fascinating about hummingbirds.  As such, it begs the question, “What will researchers discover next about these amazing birds?”