Ask a scientist

What does it sound like when doves cry?

Much to the dismay of the artist formerly known as the artist formerly known as Prince, according to some cursory research, very few non-mammals actually cry. So asking the question “is this what it sounds like when doves cry?” is akin to asking what the sound of one hand clapping is, and I don’t think Prince was that deep.

While some animals do make sounds of distress — mostly mammals trying to get the attention of their mothers — crying when you’re upset or injured seems to be a uniquely human attribute. If you look at the issue from the perspective of a predator/prey relationship, vocalizing the fact that you are injured and vulnerable to things that want to eat you is rarely a good idea. This does not, however, mean that bird eyes are not super cool.

While the average human has a field of vision — or the amount of area your eyes can cover at any one time — of 180 degrees out of a possible 360, some birds can see a full 340 degrees around their head. This is important since, unlike us humans who can swivel our eyes all around in their sockets, most bird eyes are fixed in place. This is also why birds move their heads around so much when looking at things.

Bird eyes also differ from ours in the department of head-to-eye ratio. Human eyes only make up a measly one per cent of the total head in terms of weight, while bird eyes can make up almost 15 per cent. This is partially due to the fact that birds have larger eyes for a given size of head than humans, and partially due to the fact that bird skeletons are very light, to facilitate flight.

And finally, assuming that just because birds don’t cry means that they don’t have the ability to cry would be a mistake. According to Scott Forbes of the University of Winnipeg, like humans, birds have tear ducts which secrete watery tears that protect the eye. Furthermore, some birds, such as those which live near salt water, even have ducts which make oily, waterproof tears.
So birds could cry if they wanted to, they just choose not to.

One more unrelated bird-eye-fact: there are moths in Madagascar who actually feed on the tears of sleeping birds by pushing a “harpoon like” projection into the bird’s tear-duct. W-eye-ld!