When the nose doesn’t always know
The world is full of amazing things. Some things we understand, some we don’t, and some we think we understand until we discover otherwise.
Somewhere, sometime, I picked up the “fact” that all birds lack a sense of smell. I’ve shared this with others and come to believe it. It seemed to make sense. Birds are so colorful and sing, so they must use sight and sound. But smell? I never questioned it or researched more.
The uncomfortable but necessary time came when someone told me I was wrong. In fact, all birds have body parts that allow them to smell. It is still unclear how developed this sense is in all birds. Research shows that for some birds a sense of smell is critical to their survival.
How did this idea get started and how did it change? The idea that birds lack a sense of smell can be traced back to John James Audubon. In the late 1700s and early 1800s, Audubon traveled throughout America studying, gathering and painting birds. In 1820, he did two experiments with the infamous scavengers of dead animals, Turkey Vultures.
In one test, he stuffed a deer skin with grass and placed it in a field. He watched vultures fly down, rip open the deer but find not meat to eat. Then he placed a dead pig, which had been sitting in the summer heat for days, under a pile of brush. He watched the vultures fly over but never down to eat the rank-smelling pig. From these experiences he determined that Turkey Vultures can’t smell. They must find food by sight, he concluded. Over time, this idea spread to include all birds and was shared as fact.
It wasn’t until the 1960s that this truth was tested and different results were found. Kenneth Stager repeated Audubon’s experiments and showed that Turkey Vultures actually prefer freshly dead food and appear to smell it miles overhead.
After this discovery, the narrow field of bird olfactory sense appears to be dominated by women. Their research moved the needle away from myth, and more toward what is true. It seems fitting to share their story in March, which is Women’s History Month.
Betsy Bang was a passionate birder and talented medical illustrator. In the 1960s, she examined bird skulls and discovered their nasal passages were very similar to dogs. If a dog uses this trait to explore the world through smell, do birds? That question led her to look at bird’s olfactory bulbs, the part of the brain that receives smells. She discovered some birds had larger olfactory bulbs than others, indicating that smell was more important to some birds than others.
At about the same time Bernice Wenzel also became curious about birds’ sense of smell. As a physiology professor at UCLA, she tested birds’ physical response to smells. Starting with pigeons, she found that bird’s heart rates increased and their brains responded when they were exposed to scented air. Over 25 years of study, she found the same reaction in vultures, quails, penguins, ravens and ducks. She spoke and wrote on this topic extensively.
Gabrielle Nevitt, a sensory ecologist, heard one of these talks and was inspired to study seabirds. She sought out Antarctic-bound ships and, in 1991, she arrived onboard a ship with kites, gallons of fishy-smelling oil and large boxes of tampons. She soaked the tampons in the oil and flew them from kites. Dozens of seabirds were attracted to the odor, which was similar to the smell of marine fish and crustaceans these birds eat.
Nevitt has continued to research ocean-dwelling birds, including petrels, albatrosses, and shearwaters. These birds spend most of their life at sea. Nevitt is finding that these birds use smell to map out where and when to feed in the vastness of the ocean.
This story reminds me that much what we know today is because of the past work of others. We are standing on the shoulders of giants, but the past work didn’t answer all of our questions. The past provides us with a base from which to jump into new ideas. Sometimes that base is wrong, so continue to be curious and ask questions.
This story also reminds me to be humble. There are so many things we just don’t know yet. Sometimes learning feels less like getting things right and more about being less wrong. We do the best we can. As we learn more we do better.
Audubon Community Nature Center builds and nurtures connections between people and nature. ACNC is located just east of Route 62 between Warren and Jamestown. The trails are open from dawn to dusk and birds of prey can be viewed anytime the trails are open. The Nature Center is open from 10 a.m. until 4:30 p.m. daily except Sunday when it opens at 1 p.m. More information can be found online at auduboncnc.org or by calling (716) 569-2345.