Masters of the night sky
Posted on homepage: 26 July 2021 (GMT+10)
Owls are intriguing, majestic birds, with their large eyes, earlike tufts on their heads, noiseless flight, and characteristic night-time hoots. They live on every continent, except Antarctica. These birds are solitary and are usually active during twilight or at night. Some species, such as the burrowing owl (Speotyto cunicularia) and the short-eared owl (Asio flammeus) are active during the day.
Owls eat insects and/or small animals such as rodents. Some species, such as the Eurasian Eagle Owl (Bubo bubo) have even been known to kill roe deer fawns.1
Two families of owls are known today, the true owls (Strigidae) with 25 genera and 190 species (figure 1a), and the barn owls (Tytonidae) with two genera and 20 species (figure 1b). True owls can have ‘ear tufts’ (symmetrical displays of feathers which are not actually ears, figure 2) and have larger eyes and smaller beaks. Barn owls have a heart-shaped face, and long legs. Their eyes are generally smaller than those of true owls, and their bills longer.
Owls range in size from 13 cm (five inches) high for the Elf Owl (Micrathene whitneyi) to the Great Gray Owl, Strix nebulosi, at 82 cm (2.75 ft). As opposed to most other birds, female owls are larger and more colourful than the males.
How do owls see at night?
Owls have characteristically large eyes, which can be up to 5% of their body weight—100 times the ratio in humans.2 Their eyes are much more sensitive than ours to light and motion, and contain a relatively high density of light-detecting rod cells, used in night vision in all creatures. There are up to one million rod cells per square millimetre (psm) in an owl’s eye compared to about 200,000 psm in a human’s.3
Unlike many other birds, owls have forward-facing eyes, with the field of vision overlapping for both eyes. This is called binocular vision, present in birds of prey. However, only owls have bony structures called sclerotic rings which hold their tube-shaped eyes in place (figure 3). So, they cannot ‘roll’ their eyes, but have to turn their heads to view their environment. However, owls can turn their heads 270 degrees in either direction or even upside down! For this, they have 14 vertebrae in their necks, twice the number in humans.
They also have a third, transparent eyelid, called a nictitating eyelid (or membrane—figure 2). This can be drawn over the eye to moisten or protect it.
Besides their acute night vision, owls also rely on the sound of prey when hunting at night. Their hearing is highly sophisticated and very sensitive; the Great Gray Owl can hear the squeak of a mouse over ¾ km (half a mile) away! Many owls have a disc-shaped face, funneling sound towards its ears (which are on this facial disc, covered by feathers). This functions like a satellite dish, and can also be moved by special muscles on the owl’s skull to adjust the focal length, like how our eye’s lens changes shape to focus light from different distances.
Owls’ ears are located under the feathers covering the facial disc. In many species the ears are placed asymmetrically (figure 4). This helps the owl locate its prey in three dimensions. When hunting, the owl will turn its head left or right, until sound waves from the prey reach both ears at once. Then, based on the difference in sound levels from above or below, the owl will move its head up or down to locate its prey.4 This targeting mechanism is so precise that the owl can locate prey within 1.5 degrees both vertically and horizontally.
Owls must fly almost silently when hunting, so they don’t alert prey to their arrival. One feature is the large wings enabling slow flight, which is less noisy. Air turbulence is broken down by comb-like structures on the primary feathers of the leading edge of the owl’s wing. The jagged edges of the owl’s secondary feathers further reduce air turbulence. The barbules of most owl feathers have hair-like structures called pennula (singular pennulum, Latin = small wing). These give a velvety feel to the wings,5 allowing the feathers to slide on one another soundlessly.6 It also increases the porosity of the wing, further reducing noise.7 This has inspired engineers to design quieter fan blades for computers.8
Owl species that hunt only fish and insects, which can’t hear the sound of a flying owl, do not have these sound-dampening traits. The original kind may have lost these through information-destroying mutations. Natural selection would not eliminate such mutations if the features they were corrupting had no effect on survival ability.
What do owl pellets tell us about owls?
Owls swallow their food without chewing it. The food first goes into the glandular part of its two-part stomach, where acid and enzymes break down the food for easier digestion. Then, the food passes to the second part, the gizzard, where the indigestible parts of the food, like fur, feathers and bones are compacted into a pellet. The pellet then moves back into the glandular stomach and is later regurgitated. Pellets are gray or black and can be found in forest areas or barns. Their contents tell us about an owl’s diet, and the type of prey species in that particular area.
Owls—one ‘kind’ or more?
It is natural to see the two major divisions in owls today as reflecting two separate created kinds, or baramins. However, the fossil owl Ogygoptynx wetmorei has traits of both Strigidae and Tytonidae, as well as its own unique traits.9 So there might be only one owl baramin of which Ogygoptynx is (or at least is closer to) the ancestral form. It is possible that this type of owl living before the Flood reflected more of the total information in its kind, before greater specialization and diversification emerged in later times. Some of that information is no longer present in today’s owls, as suggested by the extinct fossil species, the giant Cuban owl, Ornimegalonyx oteroi—it was over one metre tall.1 Not surprisingly, there is no evidence in fossils supporting the idea that owls evolved; Ogygoptynx, mentioned above, is supposedly the oldest known owl fossil, allegedly 61.7 to 56.8 million years old.10 Yet it looks just like an owl.
Summary and conclusion
Owls are interesting animals, with a complex visual and hearing system. They speak of God’s design, rather than evolution by random chance. It makes much more sense to believe what God’s Word says about these animals as opposed to evolutionary theory.
Design in the Curse?
Before the Fall there was no death of sentient animals (nephesh chayyāh in biblical terms—probably not including insects). Every beast and bird ate plants for food (Genesis 1:30). Owls therefore only became carnivorous after the Fall, though likely eating insects all along.11 So, did the owl features that aid in hunting e.g. rodents arise afterwards? Perhaps some did. Just as after the Fall, the serpent was to slither on its stomach (Genesis 3:14), the genes for some of the design features which make owls efficient predators could have been created or at least activated (God foreknew the Fall) at that time.
But not all features used for hunting nowadays need to have been designed for that purpose. There are animals with sharp teeth which only eat plants—e.g. fruit bats.12 Similarly, before the Fall, owls could have used their sharp bills and talons for eating plants—the Palm-Nut Vulture, in all morphological respects a ‘bird of prey’, still does this.13 The owl’s sound-location ability is presumably useful for locating insects even today, and pre-Fall may also have been used to find mates.
References and notes
- Nelson, V., Monumental Monsters, Untold Secrets of Planet Earth Publishing Company, Inc., Red Deer, Alberta, Canada, p. 56–57, 2017. Return to text.
- Lewis, D., Owl Eyes & Vision; owlpages.com, accessed 30 Sep 2019. Return to text.
- Jonas, J.B. et al., Count and density of human retinal photoreceptors, Graefes Arch Clin Exp Ophthalmol. 230(6):505–10, 1992. Return to text.
- Krumm, B. et al., The barn owls’ Minimum Audible Angle, PLoS One 14(8):e0220652, 2019. Return to text.
- Weger, M. and Wagner, H., Distribution of the characteristics of barbs and barbules on barn owl wing feathers, J. Anatomy 230(5):734–742, 2017. Return to text.
- Wagner, H. et al., W. Features of owl wings that promote silent flight, Interface Focus 7(1), 2017. Return to text.
- Bachmann, T. et al., Morphometric characterisation of wing feathers of the barn owl Tyto alba pratincola and the pigeon Columba livia, Frontiers of Zoology 4(23), 2007. Return to text.
- Catchpoole, D., As silent as a flying owl, Creation 40(2):56, 2018. Return to text.
- Rich, P.V., and Bohaska, D. J., The Ogygoptyngidae, a new family of owls from the Paleocene of North America, Alcheringa 5(2):95–102, 1981. Return to text.
- Ogygoptynx Rich and Bohaska 1976 (owl); fossilworks.org; accessed 4 Nov 2019. Return to text.
- Sarfati, S., When did animals become carnivorous?, 31 Aug 2014. Return to text.
- Batten, D. et al., The Creation Answers Book, Creation Book Publishers, Powder Springs, GA, USA, 2018. Return to text.
- Catchpoole, D., The bird of prey that’s not, Creation 23(1):24–25, 2000; creation.com/vulture. Return to text.