How owls have adapted to hunt successfully at night
on Jan 23, 2024Ever wondered how not only nocturnal animals, but specifically owls, hunt at night-time, and how they are successful in doing so? They have multiple different adaptations that lead to their survival.
Around our reserve the competition between different bird species is very high. We are fortunate with a wide variety of different species and one way to relieve some pressure off them is their different hunting times and prey that they go after.
While out on safari, especially in the afternoon, keep an eye out after sunset for our different owl species, more specifically the Verreaux’s eagle-owl and the Spotted eagle-owl, two of our bigger owl species we get around these parts. They are amazing to watch and even more interesting than they seem from the first glance.
Special adaptions they have:
- Rod-rich retinas on their eyes.
- Asymmetrical ears and facial discs.
- Soft feathers, almost velvet-like.
- Two main arteries running through their neck.
Let’s talk about this.
The debate about cone and rod cells in the eyes is a major point when it comes to the success of certain animals depending on their needs. Animals active during the daytime have more cone cells in their eyes, that focuses more on colour and texture. Whereas nocturnal animals have more rod cells in their eyes which focuses more on light intensity in the eye itself, either absorbing light or reflecting it away. Owls have more rod cells in their eyes, which makes it perfect for them to have clear vision at night with little to no light, giving them a major advantage as not all animals/birds have this adaptation and they can see potential prey long before they get spotted. Owls generally also have huge eyes, which gives them more room to play with the light intensity and light up the rod cells inside the eye.
Asymmetrical ears and facial discs facilitate sound localisation, making it possible for these magnificent birds to locate any sound they might hear while perched in a tree to find their next potential meal. The difference in height of ears makes it possible for them to determine what height the sound is coming from, meaning from above or below, and exactly from which direction. This gives them pin-point accuracy of where their focus needs to be.
Facial discs on the face play another vital role as these owls rely mainly on not only their eyesight, but also their sense of hearing. These facial discs will act as a sound collector, catching any sound waves that otherwise might have been missed with smaller faces as they don’t have the same surface area. It has the shape of a satellite dish which allows a lot of sound capture, and with the facial feathers it allows owls to focus sounds directly to their ears.
Owls have extremely soft feathers, so much so that they have a velvet soft touch to them. This is a crucial adaptation that they would struggle a lot with if they didn’t have it. Soft feathers make it possible for them to fly silently through the evening. At nighttime everything quietens down and, in some areas, you might even hear a pin drop with nothing making a sound. But owls virtually make no sound when flying as their wings are broad and feathers are soft, allowing air movement through the wings and feathers as they move. Their wings are also very big in comparison to their lightweight body which doesn’t put any pressure on their silent flight. With this, they can surprise their prey and have better chances of being successful in securing a meal for themselves.
With owls often needing to hold a single position before moving, not giving their location away, they need to be able to sit in one spot and cover a 360-degree radius around them. They have two main arteries running through their necks, making it possible for them to turn their necks all the way around without stopping the blood flow to their brains. In other words, if they had to turn 360 degrees to the left, the main artery on the left would be blocked off completely, but the artery on the right will still be open allowing blood circulation to carry on as normal.
Another interesting thing about owls’ eyesight is that their eyes are fixed in a position, meaning they can’t move around like a human’s eyes. You will often see an owl bobbing its head up and down, staring in one direction. With this movement they are judging the position and distance of a certain object, trying to determine if it is within reach for them. They are essentially triangulating an object, such as potential prey.
Owls will often look at prey with only one eye open, essentially giving the prey the idea that he is not looking at the prey and is facing sideways, owls will do this to pinpoint location and to wait for the potential prey animal to relax again before striking.
With other senses not as much developed they rely on their hearing a lot, and can sometimes, depending on the wind direction, pick up on sounds from as far as 10 kilometres away! They have the best sense of hearing by any animal ever tested, making it possible for them to detect even the softest break off a leaf beneath them.
These raptors are one-of-a-kind and have been developed to be fully active at night and sleep in the day. If you get lucky enough to see an owl during daytime, you will get an idea of their incredible camouflage as well. We often see ear tufts on owls which not only helps to reflect sound to the ear, but also helps them blend in with their environment in branches and trees.
Nature always has a way to teach us things we never thought of and never knew. In our classrooms we will never fully be the masters of the trade, as Mother Nature is not always understandable of what she does and how she does it. Always ask yourself the question, ‘WHY?’. Especially when seeing something you don’t know what the purpose is, everything has a purpose out here and every animal/bird has got its own adaptations to survive in the wilderness.
Blog by Ruan Mey (Earth Lodge Ranger)
