Owls are known for their large, forward-facing eyes and their ability to turn their heads almost completely around. One of the owl’s most distinctive behaviors is tilting or cocking its head to the side. This head-tilting habit has intrigued both experts and casual observers for a long time. But why exactly do owls tilt their heads?
Theories on Why Owls Tilt Their Heads
There are a few main theories as to why owls tilt their heads:
Hearing
One popular theory is that owls tilt their heads to help hear better. Owls have asymmetrically placed ear openings—one ear is higher than the other. By tilting their heads, owls can compare arrival times of sounds between their ears, which helps them pinpoint sound sources.
Tilting may also funnel sound into the owl’s ears and amplify it. Owls have facial discs made of stiff feathers that collect sound waves and direct them towards the ears. When an owl tilts its head, it may adjust the facial disc’s positioning and improve its ability to locate and hone in on sounds.
Vision
Another theory is that head-tilting is related to owls’ vision. Owls’ eyes are fixed in their sockets, so they can’t roll their eyes around to see different areas. Instead, owls have to move their whole head.
Tilting the head may allow an owl to shift its field of vision and obtain a perspective that isn’t possible with the head upright. This could help owls spot prey or get a better sense of depth and distance. The degree of head rotation depends on the owl species, but many owls can turn their heads 270 degrees or more.
Binocular Vision
Owls have good binocular vision, meaning there is significant overlap in the field of view between their two eyes. Their eyes point in the same direction, giving them depth perception and ability to judge distances.
When scanning for prey, owls typically hold their body upright but swivel their head and neck horizontally. Tilting the head 90 degrees may maximize an owl’s binocular vision by aligning its two eyes to point straight down. This could allow for sharp downward focus.
Striking Prey
For some owl species that hunt on the wing, tilting the head may help them keep visual tabs on prey before swooping down to catch it. Tilting the head so one ear tilts towards prey may also prime their auditory senses to track prey.
Once an owl has landed on the ground with prey, a cocked or tilted head gives it better visibility to deliver fatal blows with its talons. The forward-facing eyes don’t allow an owl to easily see the food beneath its own beak otherwise.
Do All Owl Species Tilt Their Heads?
Most owl species have been observed tilting their heads, but some do it more frequently than others. Long-eared owls, for example, are constantly scanning their surroundings and seem to tilt their heads more often than great horned owls.
Here are some owls known for frequent head-tilting:
- Barn owls
- Barred owls
- Burrowing owls
- Great grey owls
- Long-eared owls
- Short-eared owls
Species like the elf owl and boreal owl don’t tilt their heads as often. The degree of head-turning ability also varies between species. Owls with longer necks, like barn owls and long-eared owls, can turn their heads almost 270 degrees. Smaller owled owls have more limited rotation closer to 110 degrees.
Do Other Bird Species Tilt Their Heads?
While owls are well-known for the head-cocking behavior, other birds tilt their heads too. Birds of prey such as eagles, hawks, and falcons may tilt their heads to hone in on prey. Small songbirds can tilt their heads while foraging.
Water birds like herons and egrets may tilt their heads to spot prey in the water below. Birds tilt their heads while drinking to help swallow water. Some species tilt heads during courtship rituals.
However, owls rely on head-tilting to a greater degree than most birds because of their unique hearing and vision adaptations. Owls also hold their heads tipped for longer durations while observing their surroundings.
Why Do Some Owls Bob Their Heads?
Some owls, especially small owl species, bob their heads up and down frequently. This head bobbing differs from the sideways tilting motion.
Head bobbing likely relates to owls’ distance vision. Owls have good static vision for stationary objects. But objects in motion can appear blurry.
Bobbing may help an owl’s eyes track moving objects against a stationary background. This could make prey easier to follow with their eyes. The up and down head motion could also help owls judge distances better.
Conclusion
Owls tilt and turn their heads frequently thanks to their unique anatomies. Their asymmetrically placed ears lead many experts to think hearing plays a key role in head-tilting. But vision, binocular vision, and hunting strategies also influence an owl’s tendency to turn its head sideways.
While sight and hearing are likely both involved, scientists still debate the true purpose. There may not be one single reason owls tilt heads. Multiple factors could work together, with different factors holding more importance for certain owl species or certain situations. More research is still needed to fully understand the visual and auditory mechanisms behind this captivating owl behavior.