Scientists learn more about hummingbirds and their sense of smell

Hummingbirds are best known for their small yet powerful wings, but did you know they also have an active sense of smell? 

In a recent study done by the University of California, Riverside, and funded by the National Science Foundation, scientists uncovered how hummingbirds use their sense of smell for foraging and protection. The study involved three North American species: Allen’s Hummingbird (Selasphorus sasin), Costa’s Hummingbird (Calypte costae), and Anna’s Hummingbird (Calypte anna). These species are native to the west coast of the United States and are just a small number of the 330 known species of hummingbirds in the world. Scientific specimens of these and other hummingbird species are preserved in the DMNH scientific collections, pictured here.

From left to right: Selasphorus sasin, Calypte costae, and Calypte anna

There have been few studies on the ability of hummingbirds to use the sense of smell. Hummingbirds have olfactory bulbs, but scientists assumed the tiny birds were unable to use them because of their very small size. On the contrary, this study proves that their olfactory bulbs actually play a very important role.

Foraging is a hummingbird’s main objective, and scientists found that scent impacts their choices in locating food. The study suggests that hummingbirds use smell to identify which flowers contain the highest quality nectar. Scientists also noted the hummingbirds avoided flowers containing defensive chemicals often emitted from harmful insects, such as native wood ants (Formica francoeuri), which feed on the same nectar as hummingbirds. The scent of these chemicals was a clear deterrent to the birds, showing that their sense of smell may also play a role in protecting them from harm. By identifying the scent of harmful chemicals, hummingbirds can properly determine feeding areas that best fit their needs.

Through this study, scientists are one step closer to better understanding the importance of scent in the lives of these small yet complex birds. Learn more about the power of a hummingbird’s sense of smell in the paper published by Behavioral Ecology and Sociobiology.


Kim, A.Y., Rankin, D.T. & Rankin, E.E.W. What is that smell? Hummingbirds avoid foraging on resources with defensive insect compounds. Behav Ecol Sociobiol 75, 132 (2021).

Allen’s Hummingbird (Calypte costae)