You have certainly noticed how a dog will suddenly respond to a sound that you can’t hear. When you take a dog for a walk, it will frequently stop to sniff a smell that you can’t detect. A cat can see a mouse in a dark room that is pitch black to you.

The acuity of the senses of different species varies. It is a challenge to try to understand the behavior of a species whose senses differ so much from our own. The limitations of our senses constrain how effectively we can understand another animal’s behavior.

This constraint was first recognized in prescient work written by the German biologist Jakob Johann de Uexküll about a century ago. He proposed the concept of Umvelt, best translated as self-centered world.  Uexküll argued that organisms in the same environment may have quite different Umwelts. In other words, animals in the same habitat may experience the world in quite different ways because of the relative strength and weaknesses of different senses. Animal behavorists must avoid pitfalls by not recognizing their study animals sense the environment in ways that our own senses can’t.

Let’s compare the Umvelts of birds to our own Umvelt. In some ways, birds perceive their environment in ways we cannot sense or comprehend.

Many birds sing so it is no surprise that the sense of hearing in birds is pretty good. Our hearing acuity is similar. Our ears can hear some low frequencies birds can’t hear, and birds can hear some frequencies that are higher than we can detect.

However, birds are better at us in hearing the detail in a sound. We hear the characteristic call of an Eastern Whip-poor-will as three notes rather than the five notes a bird hears. A Winter Wren can produce a hundred notes in a single song to our ears, but birds hear far more. Those extra notes matter to a bird.

Among mammals, our vision is well developed. We have three types of cones in the retinas of our eyes that are sensitive to blue, red and green colors. Most mammals only have two kinds of cones, so the acuity of their color vision is limited.

Birds outdo us. They have four kinds of cones in their retinas and one of them can detect ultraviolet light, invisible to us. We can use technology to render objects in the environment that reflect ultraviolet light as color visible to us but, alas, we have no way to sense the world as birds too.

Armed with this information, we now know that some birds like Eurasian Starlings have patches of feathers that reflect ultraviolet light that are used in identification of individual birds. To us, they all look the same. These differences among individuals seem to be important in mate selection.

Over 100 species of birds are now known to reflect ultraviolet colors. Birds that to our eyes have similar male and female plumages like Cedar Waxwings, Barn Swallows and Eastern Meadowlarks, have different ultraviolet patterns making it easy for birds to tell males from females.

Bird eyes are better than ours in seeing details. This ability is tested using images of parallel white and black lines. By reducing the width of the lines, a test animal will ultimately see the image as a black object. Birds are twice as good as us at discerning narrow white and black lines. That means that that a bird like the Wedge-tailed Eagle can detect a rat from a mile away. No wonder that rodents are so skittish!

In general, birds have a more poorly developed sense of smell than us. There are exceptions. Pigeons smell their way back to their roosts once they get close. Albatrosses and other tubenoses can smell the oils given off by their squid and invertebrate oceanic prey. Turkey Vultures locate carrion by smell.

Touch acuity is similar in birds and humans. Humans have more taste buds than birds, so our taste is certainly more important than in birds.

Birds have one sense we lack. Birds can detect the earth’s magnetic field. This sense is particularly important in orientation and navigation for migrating birds. Despite years of research, we still do not where the magnetoreceptors are in birds.