Do Ducks Have Ears?

Yes. Ducks have ears — a middle ear and an inner ear much like ours — but no ear flap, which is why you have never seen one. The opening sits slightly behind and below each eye under a patch of soft feathers. A mallard hears from about 66 hertz up to 7.6 kilohertz, hears best around 2 kilohertz, hears underwater, and starts listening to its mother several days before it hatches.

Where a duck’s ears are

Ducks Unlimited’s guide to the senses of waterfowl puts it in one sentence: “Waterfowl ears lack external appendages and are located slightly behind and below the eyes.” The feathers over them have a name and a job: “The ear openings are covered with soft feathers, called auriculars, which offer protection and help muffle the sound of the wind when the birds are in flight.” Part the feathers behind a duck’s eye and you find a hole, not an ear as a mammal would recognise it. The wildlife writer Sheena Harvey offers the reason birds went without the flap: “Having external ears would be like trying to hear a conversation with your head sticking out of a car window.” Ducks Unlimited ranks the sense second: “After sight, hearing is perhaps the second most important sense to ducks and geese.” Sight comes first, and it is a strange sense in a duck — see how do ducks see.

Inside: one bone, not three

Behind the opening a bird’s ear is built on a simpler plan than a mammal’s. Britannica’s account of hearing in birds describes “a short external passage, or meatus, ordinarily hidden under the feathers at the side of the head”, and a middle ear in which “the chain consists of an osseous inner element, the columella, and a cartilaginous extracolumella” — a single bone where we have three. The cochlea, the organ that turns vibration into nerve signals, is not a spiral: “The cochlea of birds is similar to that of crocodiles, consisting of a short, slightly curved bony tube within which lies the basilar membrane with its sensory structures.” The ornithologist Roger Lederer summarises it as “instead of three vibration-transmitting bones birds have only one, the columella”.

What a mallard can actually hear

Bird hearing has been measured properly in only a handful of species, and the mallard is one of them. In 2017 the Journal of Comparative Physiology A published an audiogram of three trained mallards, tested with pure tones from 16 hertz to 9 kilohertz. At a moderate loudness, “their hearing range extends 6.85 octaves from 66 Hz to 7.6 kHz, with a best sensitivity of 12.5 dB at 2 kHz.” Lederer gives the human range as 20 to 20,000 hertz, and here the myth of superior animal hearing fails: “at no frequency, including the lowest tested, were the ducks’ thresholds lower than those of humans.” Nor do they hear the very low rumbles some birds detect: “unlike pigeons and chickens, but like budgerigars, mallard ducks do not hear infrasound.”

What ducks are tuned to is each other. A US Geological Survey study that measured hearing in ten diving-bird species by brainstem response found peak sensitivity between 1,000 and 3,000 hertz, and then measured the birds’ own voices: “the peak frequency, i.e., frequency at the greatest intensity, of all species’ vocalizations measured here fell between 1000 and 3000 Hz, matching the bandwidth of the most sensitive hearing range.” The quack and the ear are made for each other; why the quack sounds as it does is in why do ducks quack. Across birds generally, a review presented to the Vertebrate Pest Conference notes that “Avian hearing is most sensitive to sounds from about 1 to 4 kHz”, and that birds are worse than we are at telling one pitch from another.

Hearing underwater

Sea ducks feed by diving, and hundreds of thousands of them drown every year in fishing nets. To find out whether a sound could warn them off, researchers at the University of Delaware and the Geological Survey hand-raised long-tailed ducks, surf scoters and a common eider and trained them, for mealworms, to peck an underwater target when they heard a tone. The result, published in the Journal of Experimental Biology in 2022: “all species tested share a common range of maximum auditory sensitivity of 1.0–3.0 kHz, with the long-tailed ducks and common eiders at the high end of that range (2.96 kHz), and surf scoters at the low end (1.0 kHz).” The authors suggested acoustic “pingers in the 2–3 kHz range to deter sea ducks” from nets. Ducks do hear underwater, then, and at the same pitches they hear in air.

Listening before hatching

A duckling’s ears work before it has seen daylight. Recordings of brain responses in mallard embryos, published in 1992, followed hearing “from 5–6 days before hatching through two days after hatching” and found that hearing in the middle frequencies — 1 to 3 kilohertz, where duck calls sit — was “almost complete by hatching.” The hen uses this. Ducks Unlimited describes the last days of incubation: the embryos “begin to communicate with each other by emitting clicking sounds”, and “The hen also starts to give quiet clucking sounds that may help synchronize hatching and, most importantly, are the first communication between the hen and her soon-to-emerge brood.” Its sister organisation in Canada calls those sounds “a crucial part of a process known as imprinting, in which the ducklings learn to recognize their mother’s voice.” The rest of that process is in duckling imprinting, and what a clutch is doing in its last week is in incubating duck eggs — or, day by day, in the Candling Room.

Ears that repair themselves

One thing a duck’s ear does that ours cannot: grow new sensory cells. Loud noise or certain drugs kill the hair cells of the inner ear, and in people that loss is permanent. A 1994 review in Anatomy and Embryology reported that “hair cells in the avian cochlea can be regenerated after acoustic trauma or ototoxic drug damage”, and hearing researchers at Stanford note that “Humans and mice do not regenerate hair cells, whereas fish and birds robustly regenerate hair cells.” That is why the bird ear is studied so closely by people trying to cure deafness. For the whole head, bill to auricular, open the duck anatomy explorer.