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:
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.
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I live in B.C. Canada. May 16-19 2020 , my family and I were camping fairly deeply in the bush. There were no flowering bushes , plants or wild flowers in the surrounding pine and fir forest. I put up a hummingbird feeder and within 2 hours a hummingbird came and fed. By the end of 3 days there was 4 birds. I felt sure they must have an extremely sensitive sense of smell otherwise how did they find. our feeder. So I was quite surprised to read that the thought was they had no sense of smell…..
Interesting
Sharon Marano
Thanks Sharon, that’s really interesting. Still lots that we don;t know about even these very familiar birds!
I just saw a hummingbird go to one of my trees that has been recently holed by a wood pecker. The sap is dripping out of the holes in the trunk, but it is otherwise not a place that would be energy profitable to look for nutrients. That’s what got me searching and brought me to this post. I think they must have smelled the sap, otherwise their eyesight is incredible.
Thanks Kris, that’s really interesting. That’s a lot we don’t understand about even these very familiar and well-studied birds.
What would be the anatomical evidence of the ability to smell? Or not? For example we know that domestic dogs see in B&W because they don’t have cones.
Good question Tim. There is a structure in the brain called the “olfactory bulb” and its thought the the size of this reflects the ability of animals to small – see: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4518324/
Sorry, but I can’t for the life of me believe that hummers can’t smell. Humans can change their appearance greatly from year to year…cut your long hair short, gain or lose weight, etc, but we can’t change our natural body scent. It’s like a fingerprint, everyone is different, no two alike. Yet the birds return each year, happily greeting their feeder care-takers, buzzing and dancing around your head, as if to say hello, I made it back! It doesn’t matter what you look like, they still remember you. And I believe that is only possible by our unique body chemistry, and their amazing ability to remember. I’d definiately listen to rock solid science if any were available, but till then, we need to stop saying that and stop spreading an unproven theory. JMO. Thanks so much for posting about this, I was in search for proof when I found your site.
Hi Libby – thanks for the comment, I can only agree! It’s just been one of those ‘facts’ that everyone knows and which isn’t backed up by the science (limited though that is).
I expanded on this and used it as an example of how little we know about some aspects of plant-pollinator interactions in my recent book ‘Pollinators & Pollination: Nature and Society’. If you’re interested you can find it on Amazon etc.
Best wishes, Jeff
Hi Jeff and thanks for the heads up on your book, I’ll definiately grab a copy! I want to learn and understand all that I can on the hummingbirds. I’ve been hanging feeders only a few years and not one of the 10+ year veterans, but do research trying to learn all I can. The smell issue was one of my last stumps I couldn’t wrap my head around. The 2nd link you’ve given is no longer working. If they haven’t removed it and you later update, plz let us know as I’d like to read that one too. Again, thank you so very much for this very needful topic/information, greatly appreciated!
You’re most welcome Libby. If you do get a copy of my book I think that you’ll be intrigued by my story of a Brazilian hummingbird garden.
When I was researching the hummingbird sense of smell section for the book I discovered that the Heringer et al. study was actually presented at a conference in Brazil – this should still work: http://seb-ecologia.org.br/revistas/indexar/anais/viiceb/resumos/318a.pdf
Thank you for this article. Denying that Hummingbirds have a sense of smell while offering up no actual scientific evidence to back this claim has caused me to question this claim for some time. Just as the long standing and often cited myth that fish can only remember for a few seconds. While colors in the red/orange spectrum may catch their attention first, there are a number of other colored flowers that attract them. I’ve never seen a true red or orange morning glory.
This brings another question to mind. Are there flowers that are unsuitable or even toxic to Hummingbirds? If so, would scent be a factor in the rejection of these flowers?
Thanks Katie. It’s a good question and I’m afraid that I don’t know the answer, but it’s certainly possible. As I discuss in my book, flowers are pretty sophisticated structures when it comes to manipulating pollinators!