Birds and Their Sense of Smell: Can They Smell?

Birds and Their Sense of Smell: Can They Smell?

Birds are perhaps not known for their sense of smell, but rather their powerful sense of sight and hearing. If you look closely at a bird’s beak, it’s usually quite easy to spot that birds do indeed have nostrils, called nares, which allows them to intake both air and odours. If birds have nostrils, then can birds smell?

For centuries, it had been assumed that birds were not able to smell and that they instead rely on their sight to understand and interpret the world around them. Today, researchers have proven that many species of birds do have a sense of smell and for some, it plays a huge role in their everyday behaviour.

Many bird textbooks and other sources still state that birds have a poor or non-existent sense of smell - this has caused considerable debate and researchers are now trying to ‘rewrite the history books’. With their sense of smell, many birds have 6 senses - taste, smell, vision, hearing, touch and perception of magnetic fields.

Read on to discover more about how and why birds smell and uncover why the topic has become so contentious!

Here you can see the nares on a gooses beak

Here you can see the nares on a gooses beak

Can all birds smell?

The ways birds use their sense of smell is complex and differs massively between species, but there are some telltale signs that many birds employ at least some sense of smell in their day-to-day behaviours.

For example, it’s been observed that many birds will not enter their nests if they smell predators, one example being Blue Tits who avoid the scents of weasels.

Ground foraging birds such as kiwis are observed to smell and feel their food amongst the undergrowth rather than see it, as kiwis have notoriously small and weak eyes amongst birds. Albatrosses are known to smell floating carrion from up to 12 miles away, enabling them to locate food upon the vast ocean without needing to see it.

One of the most interesting examples are European Starlings which can distinguish between different herbs by using their smell, and actually go out of their way to choose certain pleasantly aromatic plants to leave by their nests to attract females.

Researchers are still unravelling the ways in which birds utilise their sense of smell and much of this evidence has been uncovered in the last few years.

Common Starlings can distinguish between different herbs

Common Starlings can distinguish between different herbs

Do birds have noses?

Not exactly, but birds do have nostrils called nares. They don’t have the same nose structure as mammals but instead smell through their nares which also transport air into their respiratory system.

On its way through the nasal cavity, any odours transported by the air are picked up by nerves that convert scents into electrical signals that are picked up by the brain, much in the same way as other animals.

How do birds smell?

Birds intake air through their nares and on the way to their breathing sacs (as birds do not have lungs in the same way that mammals do), odours are likely sensed by olfactory nerves and carried to the brain.

One of the most peculiar aspects of birds’ sense of scent is that it varies hugely between different species, and also does not necessarily correlate with the size of their olfactory bulb, which is the main brain structure associated with smelling (olfaction).

It’s often assumed that larger olfactory bulbs signal a heightened sense of smell, but this isn’t the case with birds. Some birds which have been directly observed to utilise their sense of smell, like the Dark-eyed junco, actually have tiny - even microscopic - olfactory bulbs.

So, whilst birds probably utilise some of the same biological machinery to smell as other animals, there are some crucial differences that remain largely mysterious to science.

A Dark-eyed Junco perched on a stump

A Dark-eyed Junco perched on a stump

How do we know that birds can smell?

The eminent naturalist and ornithologist James Audubon devised an experiment in the 1820s to test whether birds had a sense of smell. By dragging a rotten hog carcass into a field, he observed that wild Turkey vultures failed to be lured in by the smelly bait.

In actual fact, Turkey vultures are only lured to recently deceased carrion, usually animals that died in the last 24 hours or so. The corpse Audubon offered them was far too putrid - the vultures were likely (and ironically) put off by the scent.

The scientific rigour employed in the 1820s was certainly not as robust as it is today and the conclusion “birds can’t smell'' was subsequently written into the ornithology curriculum.

Today, numerous experiments have confirmed that birds do smell and that some employ their sense of smell regularly, not just for survival but for courtship, mating and other purposes.

It’s still commonplace to find these explanations in textbooks; ‘birds can’t smell’ or ‘birds don’t need to smell’ or ‘don’t rely on their smell’, but the evidence is clear.

A group of foraging Turkey Vultures

A group of foraging Turkey Vultures

Can wild birds smell bird seeds?

Seeds do not emit a strong smell and thus, most birds probably do not smell wild bird seeds. Instead, they’ve likely associated the bird feeder or table with food and are alert to any motion there which might signal food.

Can birds smell humans?

There is a longstanding belief that birds will abandon their nests, eggs or young if disturbed by humans because they either see them or smell their presence. Whilst disturbing nesting birds is rarely encouraged except under extraneous circumstances, most birds will take little notice of harmless or accidental interference.

It’s probably not that birds aren’t able to smell or sense something, but more that they don’t associate that smell with danger. If, however, it was a weasel that was rummaging around in a bird’s nest and it left its telling scent behind, then some species of birds would abandon their nest to construct a new one in a safer location.

This shows that birds are informed by scents, but that there are still only specific associations between scents and danger.

Can birds smell food?

Whilst most birds hunt and source food primarily by sight, their sense of smell does also play a part in some species at least.

Several species of birds have been observed to smell food including many parrots, kiwis, albatrosses and vultures.

  • Albatrosses have been observed to smell floating carrion from distances of 12 miles, whereas parrots smell out different forms of fruits and berries when foraging.
  • Vultures use smell to identify how rotten a corpse is and kiwis use smell to locate food as their eyesight is amongst the poorest of all birds.

Many birds can smell food, but it might not be the main way they detect and search for food.

Albatrosses have been observed to smell floating carrion from distances of 12 miles

Albatrosses have been observed to smell floating carrion from distances of 12 miles

Are birds odourless?

Birds are quite hygienic and clean themselves regularly. However, some do secrete oils and other compounds which keep their feathers healthy and these can have a strong odour.

Some bird nests have a very strong smell. Generally speaking, though, birds are relatively odourless animals - even the droppings of a healthy bird generally have a weak smell.

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