Mark Twain once said, “it’s not what you know that kills you, it’s what you know for sure that ain’t true.” I wrote a column on turkey vultures several months ago and stated that they were the only bird around with a well-developed sense of smell; the implication being that other birds couldn’t smell at all. It’s been accepted for as long as I can remember that birds, with a few notable exceptions, didn’t bother much with the sense of smell. Compared to mammals, the olfactory bulb, the part of the brain that controls smell, is small and poorly developed in most birds. The idea that birds couldn’t smell can be traced back to one of the greatest bird men that ever lived, Audubon, himself. He performed a test to “prove” that turkey vultures couldn’t smell by hiding a decaying hog under some bushes. No vultures appeared to consume the odiferous, but hidden, offering. He took that as proof that they couldn’t smell it. We now know that vultures can detect even very faint smells of carrion, their normal food, from high in the air and far away. Although vultures can and do eat some pretty nasty dead stuff, they really prefer that their food be fresh dead. The vultures in Audubon’s area were using their well-developed noses to say “no thanks” to his rotten offering.
Recent research I read about in the August/September issue of National Wildlife magazine has poked holes in the prevailing logic on bird’s sniffing abilities. Though the olfactory bulb that controls smell may be small and poorly developed in most birds, it’s there. Other research has shown that even small parts or poorly understood parts of the brain still function at some level. It turns out that many more birds than originally thought use their sense of smell, even though small in comparison to some other creatures. They use it in feeding, breeding and other behaviors.
I have often wondered why birds seem to find food placed for them in specialized feeders, like tube feeders. The tubes look like nothing in nature where they’d find food, but it doesn’t take long for birds to find and begin using a new feeder station. It may be their curiosity when something new appears in their environment, but maybe it’s their sense of smell that tells them there’s food in there. They may not be able to smell a wide range of odors like most mammals, but perhaps their small range is specially keyed to note odors that are important to them in finding specific foods.
Starlings, according to the article, use their limited sense of smell to locate aromatic plants that they bring to their nests in order to repel pests. How do colony-nesting birds know which nest or which young are theirs? Smell is likely part of the answer. It’s now known that the huge wandering albatross can detect the smell of foods like squid from as far away as twelve miles, and follow that plume of scent to its source as they soar over stormy southern oceans on their 11-foot wings.
I’m thankful that my incorrect assumption that most birds can’t smell didn’t kill me, but it reminds me that there are probably some other things that I (and probably most of us) “know for sure that ain’t true!” Which one of those firmly held beliefs “that ain’t true” might be one that could kill me? We must be open to questions and new truths as science and testing reveal them, even when it challenges long-held beliefs or forces us to confront behaviors that aren’t in our best interest. I’m pretty sure that the next few years will reveal other faulty, long-held assumptions, and hope that we’re not too stubborn to be willing to change our thinking and our ways.