I was contemplating my parakeet the other morning when my wife was cooking something very aromatic, and it occurred to me -- can birds smell? I've never seen Woody sniff his dish of seeds or hold his nose when I open a cat food can, but other animals can smell things, and he has little holes in his beak, so...?
-- Woody's Owner, Chula Vista
It does make you wonder what Woody's little nose holes are for if he can't smell cabbage or cigars. I can't answer with certainty for parakeets, but it's been shown in laboratory studies that most birds' olfactory nerves are stimulated by odors. So you might say that, technically, they do "smell" things. But it's an unusual bird that reacts to an odor. In the grand scheme of things, a bird's senses of smell and taste are relatively unimportant to preserving its life or reproducing its species. Pelicans' nostrils are completely covered, like natural nose clips, I guess. Their olfactory structures are almost nonexistent, so it would appear that a sense of smell serves no purpose for a species that finds its dinner by soaring over the water, looking for fish.
At the other end of the spectrum is the flightless kiwi, the New Zealand bird best known to Americans as the lumpy animal on the shoe polish cans. The bird brains figure it has the best-developed sense of smell of any bird. It's a nocturnal feeder that spends its humble life scuffling through piles of leaves and debris, searching for earthworms. A kiwi's nostrils are at the tip of its beak, and it sniffs its way along the ground as it feeds.
Vultures are the second-best smellers. They like road kill and other dead things, so I don't have to draw you a diagram to explain how critical a vulture's nose is. They use smell to get a general sense of where the corpses are, then use their eyes to find them. Certain sea birds use their sense of smell to locate their nests. Scientists stuffed homing pigeons' nose holes with cotton, then released them. When hardly anybody made it back, they decided that the birds sniff the air to orient themselves to where they are relative to where they want to go. African honeyguides find hives by smelling the wax. A beeswax candle works just as well.
A few more patented Matthew Alice facts will show how taste probably isn't a big deal to Woody either. The average chicken has 24 taste buds. Woody's relatives, parrots, have about 350. Man 9000; rabbits 17,000; catfish 100,000. Don't bother adding gravy to Woody's dinner. He just won't care.