While many people wonder how birds locate food sources like bird feeders, their sensory world is more complex. Birds do possess a sense of smell, but it’s often not their primary tool for finding bird seed.
Understanding Avian Olfaction
Birds possess an olfactory system, but its development varies greatly across species. The size of a bird’s olfactory bulb, which processes scents, indicates its sense of smell strength; generally, a larger bulb suggests a more developed sense. For many common backyard birds, their sense of smell is relatively weak compared to other senses.
All birds possess an olfactory bulb, though its prominence varies. While some species have a less prominent olfactory system, they still detect odors. The capacity for smell in birds is diverse, ranging from highly acute in some species to barely discernible in others, reflecting their varied ecological needs.
How Birds Actually Find Your Feeder
For most birds visiting backyard feeders, vision is their dominant sense for locating food. Their eyesight is exceptionally keen, allowing them to spot feeders, individual seeds, and other birds from remarkable distances. Many species can perceive ultraviolet light, which allows them to see colors and patterns invisible to the human eye, potentially making certain seeds or feeder designs stand out.
Birds also rely heavily on memory and learned behaviors to find feeders. Once a bird discovers a reliable food source, it remembers the location and returns regularly. They can even learn to associate human routines, such as filling a feeder, with new food availability. Social cues also play a significant role; birds observe each other, and the presence or calls of other birds at a feeder can attract newcomers. This collective behavior often leads to a rapid increase in feeder visitors. For these common feeder birds, the scent of bird seed typically plays a very minor role, if any, in their discovery of the food source.
When Smell Really Matters for Birds
While smell is not primary for finding bird seed, it is highly developed and crucial for certain bird species in specific contexts. Turkey Vultures, for example, possess an exceptional sense of smell, allowing them to locate carrion from great distances. They are particularly sensitive to ethyl mercaptan, a gas released during decomposition, which enables them to find carcasses hidden from view.
Kiwi birds, unique to New Zealand, are nocturnal and rely heavily on smell to forage for insects and worms underground. Their nostrils are at the tip of their long beaks, enabling them to probe the forest floor and sniff out prey.
Seabirds, such as petrels and albatrosses, also exhibit a highly developed sense of smell. They use this ability to detect dimethyl sulfide (DMS), a compound released by phytoplankton, guiding them to rich feeding grounds in the vast ocean. These examples demonstrate the diverse and specialized roles olfaction plays in the avian world, extending far beyond the typical backyard feeder.