Do Birds Have a Good Sense of Smell?

Yes, birds do have a sense of smell, and in some species, it is surprisingly well-developed. While the long-standing myth that birds rely solely on sight and sound has persisted for decades, modern ornithological research confirms that many bird species possess a functional and sometimes highly sensitive olfactory system. This challenges outdated assumptions about avian sensory perception and opens new understanding into how birds navigate, forage, and communicate. The question do birds have a good sense of smell reveals a complex answer: it varies significantly across species, with some relying heavily on scent while others use it minimally.

The Evolutionary Misconception About Bird Olfaction

For much of the 20th century, scientists assumed birds had little to no sense of smell. This belief stemmed from early brain anatomy studies showing that the olfactory bulbs—the parts of the brain responsible for processing smells—were small or underdeveloped in most bird species examined at the time. Early researchers, focusing primarily on songbirds and pigeons, concluded that vision and hearing were the dominant senses in avian life, relegating smell to an evolutionary afterthought.

However, this generalization overlooked the vast diversity among the more than 10,000 bird species worldwide. As neuroimaging and behavioral experiments advanced in the late 20th and early 21st centuries, scientists began discovering that certain birds not only detect odors but use them for critical survival tasks. These findings reshaped our understanding of avian sensory ecology and raised new questions about the role of smell in bird behavior.

Bird Species With Exceptional Olfactory Abilities

Not all birds are created equal when it comes to smelling. Some species have evolved highly refined olfactory systems adapted to their ecological niches. Among the most notable are:

• Procellariiformes (Tubenoses): This order includes albatrosses, petrels, and shearwaters. These seabirds have large olfactory bulbs and tube-like nostrils on their beaks, which help them detect dimethyl sulfide (DMS), a chemical released by phytoplankton when eaten by krill. By following DMS plumes over vast oceanic distances, these birds can locate food sources even in featureless marine environments.
• Vultures: Turkey vultures (Cathartes aura) are famous for using smell to find carrion. Unlike most raptors that rely on sharp vision, turkey vultures can detect the odor of ethyl mercaptan—a gas produced during decay—from miles away. This allows them to locate dead animals hidden beneath forest canopies where visual detection would be impossible.
• Kiwis: Native to New Zealand, kiwis are nocturnal ground-dwellers with tiny eyes and long beaks equipped with nostrils at the tip. This unique adaptation enables them to sniff out insects and worms buried in soil, essentially "smelling" their prey before pulling it out.
• Starlings and Other Passerines: Recent studies show that European starlings use scent to assess the freshness of nesting materials, preferring aromatic herbs that may repel parasites. Similarly, some warblers appear to distinguish between individual scents, suggesting social or reproductive uses for olfaction.

Bird Group	Olfactory Bulb Size	Primary Use of Smell	Example Species
Tubenoses	Very Large	Locating food over oceans	Wandering Albatross
New World Vultures	Large	Finding carrion	Turkey Vulture
Kiwis	Enlarged	Foraging in dark/soil	North Island Brown Kiwi
Passerines (some)	Small to Moderate	Nest selection, mate choice	European Starling
Pigeons & Doves	Small	Limited; possibly homing	Rock Pigeon

How Scientists Measure Avian Olfaction

Determining whether birds can smell—and how well—requires careful experimentation. Researchers use several methods:

• Anatomical Studies: MRI and CT scans reveal the size and structure of olfactory bulbs relative to overall brain volume. Larger bulbs generally indicate greater reliance on smell.
• Behavioral Experiments: Birds are presented with choices between scented and unscented options (e.g., food, nesting material). Preference indicates olfactory sensitivity.
• Field Observations: Tracking birds like albatrosses via GPS shows they follow wind-borne chemical trails, supporting the idea that they navigate using scent.
• Molecular Analysis: Genetic sequencing identifies the number of functional olfactory receptor genes in different species. For example, kiwis have far more such genes than chickens or zebra finches.

These tools collectively confirm that olfaction plays a measurable role in avian life, though its importance varies widely across taxa.

The Role of Smell in Bird Behavior and Ecology

Smell influences multiple aspects of bird biology beyond just finding food:

Navigation and Migration

Some evidence suggests that certain birds may use environmental odors as navigational cues during migration. Seabirds, in particular, could be integrating scent maps with magnetic and celestial navigation systems. Though less studied than other mechanisms, olfactory navigation remains a plausible hypothesis for species crossing open oceans.

Mate Selection and Reproduction

In species like storm-petrels and some ducks, individuals emit species-specific scents through preen gland secretions. These odors may signal genetic compatibility or health status, playing a role in mate choice. Female Leach’s storm-petrels, for instance, can identify their mates and chicks by scent alone in crowded breeding colonies.

Nest Defense and Parasite Avoidance

Several bird species incorporate aromatic plants into their nests. European starlings add wild carrot and yarrow, which contain volatile compounds that deter mites and flies. This behavior, known as "nest fumigation," implies an awareness of chemical properties and potential benefits—an indirect use of smell for fitness enhancement.

Parent-Offspring Recognition

In dense colonies where thousands of nests are close together, auditory and visual cues may not suffice for identification. Crested auklets and other colonial breeders use distinctive plumage scents to recognize kin. Chicks also develop unique odors, helping parents avoid feeding the wrong offspring.

Why the Myth Persists: Challenges in Studying Bird Smell

Despite growing evidence, the idea that birds don’t smell persists due to several factors:

• Human Bias: Humans are poor smellers compared to many mammals, so we tend to underestimate olfaction in other animals unless it's obvious (like vultures circling above roadkill).
• Methodological Limitations: Testing smell in flying animals is logistically difficult. Controlled lab conditions may not reflect natural behaviors.
• Focus on Model Species: Much early research centered on pigeons and chickens—species with limited olfactory ability—leading to overgeneralized conclusions.
• Lack of Public Awareness: Popular media and educational materials often repeat outdated facts, slowing public acceptance of new science.

Implications for Birdwatchers and Conservationists

Understanding avian olfaction has practical applications:

• Improved Observation Techniques: Knowing that some birds respond to scents can inform ethical birding practices. For example, using strong perfumes near sensitive species like kiwis might disrupt natural behaviors.
• Conservation Strategies: Protecting chemical cues in ecosystems—such as DMS production in healthy oceans—is vital for tubenose survival. Pollution and climate change can alter these signals, indirectly affecting seabird foraging success.
• Wildlife Rehabilitation: Rehabilitators working with kiwis or vultures should consider olfactory enrichment in enclosures to promote natural foraging instincts.
• Eco-Tourism Design: Viewing platforms near albatross colonies should minimize human odors (e.g., cooking smoke, fuel) that could interfere with nesting birds’ sensory environment.

Debunking Common Misconceptions

Misconception #1: "All birds have no sense of smell."
Truth: While many birds have limited olfaction, numerous species rely heavily on it. Generalizations across 10,000+ species are inaccurate.

Misconception #2: "Birds only use sight and sound."
Truth: Multisensory integration is common. Many birds combine visual, auditory, and olfactory inputs for decision-making.

Misconception #3: "If a bird has a small nose, it can’t smell well."
Truth: External nostril size doesn’t correlate directly with olfactory ability. Kiwis and tubenoses have specialized nasal anatomy optimized for scent detection.

Future Research Directions

Ongoing studies are exploring:

• The genetic basis of olfactory receptor diversity across bird lineages.
• How urbanization and air pollution affect birds’ ability to detect natural odors.
• Whether migratory landbirds use plant or soil volatiles as orientation cues.
• The role of microbiomes in producing socially relevant scents.

As technology improves, we can expect more nuanced insights into how birds experience the world through smell.

FAQs About Birds and Their Sense of Smell

Can pigeons smell?

Pigeons have relatively small olfactory bulbs and limited evidence of scent-based navigation. While they may detect strong odors, they primarily rely on visual landmarks and Earth’s magnetic field for homing.

Do birds smell bad?

Most birds are clean and lack strong body odor due to efficient grooming and feather maintenance. However, some species like hoatzins produce a musky smell from fermenting gut bacteria, earning them the nickname "stinkbird."

Can birds smell humans?

There is no strong evidence that birds detect human scent in the way predators do. However, they associate humans with sounds, movements, and routines. In sensitive species like kiwis, strong human odors might cause stress.

Do scavenger birds smell death?

Yes, particularly New World vultures like the turkey vulture. They detect gases like ethyl mercaptan emitted by decaying flesh, allowing them to locate carcasses from great distances, even under dense canopy cover.

Are there birds that use perfume?

In a sense, yes. Some birds, like crested auklets, produce sweet-smelling plumage scents during breeding season. Others, like starlings, choose aromatic nesting materials that may act as natural insect repellents—functionally similar to using perfume for protection.