One of the general features associated with specialised hummingbird-pollinated flowers in the New World is that they often have no scent perceptible to the human nose. This is then interpreted as evidence that hummingbirds have no sense of smell, which strikes me as circular reasoning at best. This “fact” is then frequently repeated in text books and on the web, for example at the Bird Watcher’s Digest site, at The Spruce site, and at the World of Hummingbirds.
However I know of only two research papers that have tested whether or not hummingbirds can smell, both of them short notes; and in both cases they found that the hummingbirds they tested could associate scents with food in artificial flowers. Those studies (with links to the originals) are:
Heringer, H. et al. (n.d. – c. 2006?) Estudo da capacidade olfatória em três representantes da subfamília Trochilinae: Eupetomena macroura (Gould, 1853), Thalurania furcata eriphile (Lesson, 1832) e Amazilia lactea (Lesson, 1832). Unpublished manuscript – possibly a student project (?)
It surprises me that this has been so little studied, given how much research has otherwise been done on hummingbirds. Have I missed any other studies? Clearly vision is more important for hummingbirds when locating food, but that’s not the same as stating that hummingbirds have no sense of smell. Seems to be one of those myths that won’t go away, of which there are many in pollination biology.
Comments welcomed, as always.