Is it possible that birds use vision in place of smell? When a fruit or a flower puts out a fragrance could the fragrance be seen in ultra violet ranges? It amazes me how some birds are able to locate food just by flying over. Most birds are said to have very weak senses of smell simply because their olfactory glands are not very well developed. Is it possible that they are just very specific in what they can smell?. I used to have a few plants in my yard that produced tiny berries, somehow when they ripened these unusual birds I seldom ever saw would just appear to feed on the berries, I wouldn’t see them again until the following year.
The specificity question is a very good point and doing a quick Google scholar search one that is being actively researched. Here for example:
https://onlinelibrary.wiley.com/doi/pdf/10.1111/1749-4877.12694
In terms of how they experience that specific smell? No way to know. No reason to think it is experienced as sight but …
Welll… in what way?
Birds not only see a greater range of colors than we do, they also have much greater visual acuity, that is, their vision is in higher definition than ours. They can spot something at a much greater difference than we can. So, sure, when it comes to locating food they are relying on vision and will spot food items at a much greater distance than we are able to. As opposed to, say, a dog which will follow a scent to find food.
I happen to live with a small, colorful bird (he’s a parrot). He definitely responds to the sight of food, including trying to go after food he can see inside of a sealed container. When approaching a food dish he does look intently at the contents, then will touch it with his beak and tongue before eating it. Except when he just wolfs down something familiar. So it’s not just vision they’re using.
There are some birds that do have a good sense of smell - turkey vultures, for example, are known to follow odors. That’s why they’ll circle above a leak in a natural gas pipeline, to them it smells like something dead, which for them means food, and they’re circling looking for a carcass. But those seem to be the exception. Most birds don’t seem to have a good sense of either smell or taste, though they definitely are capable of some smell and taste detection. Your own senses of smell and taste are probably superior to that of the average bird, assuming you’re an average human.
But, although my bird does known some English he is not fluent enough in human language that I can ask him directly how he experiences the world and get an answer useful for the purpose of answering your question.
Thanks for posting that, it might be a few hours before I have time to read it but it does look interesting, and it does address what I am thinking about.
For most birds, they almost certainly do - but they’re not seeing aromatic vapor, they’re just seeing the object itself. They have to see well to fly (and predatory birds have to see well to hunt), so they’re pretty damn good at spotting food as well:
A good example of this is hummingbird feeders. You’re supposed to stock them with plain sugar water. While the water may evaporate, the sugar does not, so you wouldn’t expect them to emit any detectable odor. Hummingbirds find them by looking for the bright colors they are typically made of.
Predatory birds are looking for living prey and hunt from well above, where they’re unlikely to smell what they’re after.
@DSeid has pointed to one exception for tropical birds that use their sense of smell to help find desirable fruit. One other exception is certain vultures that live in forested areas, which are known to find dead animals by smell. They have more difficult time finding fresh meat than they do decaying meat - although, in what must be a frustrating trait for them, they prefer to eat fresh meat. Vultures that live in open terrain are more reliant on their vision.
Vultures have a strong sense of smell used to detect carrion. For many birds smell is not that useful because they search for food from high up and their eyesight is a more valuable tool, but there is the possibility that strong olfactory senses existed in the ancient ancestors of birds that are frequently depicted in movies. More recently large flightless birds were once dominant land predators and a sense of smell would have been more useful for them. The natural history shows the possibility of many variations of ability.
Somewhere on the board the ability of birds to find bird feeders has been discussed. The general conclusion is that bird’s keen sense of sight allows them to locate bird feeders. This seems to be confirmed with the use of clear panels on bird feeders. Presumably bird feeders without visible contents have been tried and less successful.
You are right that most birds do not have a good sense of smell, as far as we can tell. Most birds have a very good sense of vision. Owls rely a lot on hearing, facilitated by their bowl shaped heads.
One bird that does seem to have a good sense of smell is the American turkey vulture, which can smell rotting meat from miles away.
Actually the introduction lists many examples of very specific olfactory cues used across multiple species, not just frugivores and scavengers.
The OP’s speculation that a very specific narrow range may be sensitive and important even if the sense overall is not strongly developed is apparently correct for many examples.
Sorry I have no cite, but ISTR reading of a study where they put out uncovered and camouflaged carcasses, and the results suggested that even tho vultures had a good sense of smell, they seemed to rely more heavily on sight.
There are a TON of fascinating resources on avian abilities. I urge you to check your local library.
Well if we’re going by recollection without cite I’ll throw in that I recall smell brings them in from a distance and the sight of another vulture diving down is the biggest visual cue.
Fair enough. I am likely misremembering. I see turkey vultures may rely on smell more whereas black vultures rely more on sight.
For anyone who really wants to get into the avian olfaction weeds …
“ Recently, Potier et al. (2019) showed that both turkey vultures (Cathartes aura) and Southern caraca- ras (Caracara plancus) interacted more with a stainless- steel perforated ball containing the odor of putrefied meat compared with an odorless but otherwise identical control ball, suggesting that both species are able to use olfactory cues for foraging. Moreover, turkey vultures seemed to disregard associated visual information when it conflicted with the olfactory cue, which is consistent with the suggestion that olfaction is the predominant sense in turkey vultures (Potier et al., 2019).”
But still much more! Mate choice, predator detection, nesting material, and so on. Despite less than generous olfactory bulbs they do use smell well.
No I have not read the whole thing. Might though. It is interesting.
Could birds possibly use spectrometry more than we think they do?
“Spectrometry”, here, just means “color vision”. We already know birds’ color vision is better than ours, but much worse than a full spectroscope. It’s not that hard to test.
Instead of a full spectroscope what about very specific colors, has this been tested?
Yes.
Keeping in mind that there are something like 11,000 species of birds so any following statement should be considered a general rule with exceptions and not a mandate…
Most birds see a larger spectrum than mammals, including humans, do. They can see all the colors we can see AND into the near ultraviolet. While we humans have three types of cone cells to detect color birds have four,
Pretty much in any way you can imagine birds have better vision than we do - they can see farther, have a larger visual field, more colors… the only way in which their vision is less than ours is in low light. Birds have poor night vision and their eyes take longer to adjust to darkness than ours do. (Exceptions to this last could include night hunting birds, but those often have exceptional hearing and rely on that a great deal)
Operative term is “most birds,” the aforementioned owls tend to be nocturnal and most are completely color blind - meaning they see shades of grey, not even the relatively impoverished color vision that many mammals have vs. humans. Conversely they have a much better developed night vision, and are much better at detecting movement.
Measuring the genetics (opsin expressing genes) is a way to determine whether an animal may or may not have certain capabilities, but things like behavioral tests are also supporting evidence for an actual usable ability to discriminate hues.