By Caitlin J. Waddick, PhD, MCRP
If you were an owl, your eyes would be as big as grapefruits! You could see in the dimmest of light, as the sun or moon just begins to rise or set. If you were an owl, your ears would be so big that you could stick your fists in them! Your hearing would be so keen that you could hear your prey under leaves, snow, or grass. If you were an owl, you could turn your head 270 degrees around in its socket, almost three-quarters of a full circle.
In Hands-On Nature at Shelburne Community School, EEE and K-3 students are learning about owls, especially the unique adaptations that differentiate them from other birds of prey. While other birds of prey rely on exceptional vision or speed to hunt during the day, most owls hunt at night using the element of surprise. Owls are the stealthiest of birds.
Students compared the flight feathers of owls with other birds of prey and found that owl feathers are fuzzier and have a matte texture, while other birds’ feathers are comparatively shiny and smooth. The fuzziness of owls’ feathers dampens the sound of owls’ flight. When an owl flies through the air, a prey never hears the movement of an owl’s wings in the wind. The owl is suddenly beside it and – snatch! The prey will be in its sharp claws as the owl flies to a tree to perch.
In the classroom, the niftiest thing the students did was to study owl diets by dissecting owl pellets. Owl pellets are the indigestible parts of the prey, such as bones, scales, and fur. Many species of owl will eat their prey whole. After digesting the soft muscle and organ tissues, the remains collect in the gizzard, where it collects until it blocks further digestion. The owl regurgitates the pellet, which is a little like vomiting, but different.
The pellets take the form of a compact ball. Not to worry – the pellets the students dissected were sterilized in a commercial autoclave so that they exposed no one to pathogens. Most of the pellets came from barn owls whose diet consists entirely of voles, which are better known as field mice. Students could identify their skeletal parts using vole bone charts: hip bones with a ball and socket joint, leg bones, curved rib bones, skulls, lower jaw bones with teeth (molars for grinding), vertebrae, and shoulder blades. These skeletal parts had to be separated from a thick mash of impacted fur.
In general, owls eat mice, shrews, voles, field rats, pocket gophers, moles, crayfish, large insects, and small birds. The pellets contain whatever the bird has eaten and has not digested, which could contain non-food items, such as tin foil and rubber bands.
Children also compared different owl species, especially those of New England. The smallest owls, such as the saw-whet and the screech owls, were only seven inches tall and the largest, such as the snowy owl, were three times as big.
Classmates also practiced the calls of different owls and used the calls to identify the birds. It seems that few owls say, “Who?” Some calls sound like muffled hooting, nasal barking, high and wheezy barking, the whinny of a horse, the yipping of a little dog, a steady monotone syllable, quacking, or a high-pitched and drawn-out scream.
The many variations in owl calls allow members of the same species to locate or identify each other, to court, defend territory, create alarms or warnings, feed their young, or communicate in a group. It is owl mating season in Vermont now so keep your eyes out and your ears peeled. You may see or hear one soon!