Owls and the Importance of Predatory Birds
Photo: Barred Owl, Roanoke River, Williamston NC. Photo by Clay Barber
Owls are fascinating creatures. They are beautiful birds with big eyes that make iconic hooting sounds, but they are, above all, incredible hunters. Because of this they have large impacts on the ecosystems in which they live, but their position near the top of the food chain makes them sensitive to changes that occur within it. The animals owls eat must be plentiful and healthy enough to support them, and what the prey of an owl consumes must be plentiful and healthy enough to support it. This principal repeats itself down the food chain. So when predators like owls are abundant and healthy it is usually a sign of a balanced ecosystem. If health or numbers of predator species decline, something may be occuring within the environment that is altering the natural food web. This means that, from a conservative point of view, birds like owls are important to monitor.
What Makes Owls Such Great Hunters?
Owls have special tools that give them an edge over their prey. They have incredibly sensitive vision and hearing, silenced feathers, piercing talons, and super sharp beaks. Additionally, their heads can rotate up to 270 degrees. This allows them to place their eyes and ears in specific positions to better locate other animals. Some owls have tufts of feathers that stand atop their head were one might expect ears to be, but they are not ears at all. Unlike external protruding human ears, the hearing structures of a bird are internal. The earholes of owls that primarily hunt in the dark are asymmetrical, meaning they are offset from one another, one being higher or lower than the other. This ear positioning, and the satellite shaped feather configuration of an owl’s face, allows them to triangulate the sounds of prey in darkness or cover.
Owls are also equipped with very special feathers that silences their flight. You may not imagine that bird feathers are all that noisey to begin with, but when compared with other birds of prey, like the falcons or hawks, owls are almost completely silent in flight. It is strange to see something so large glide so quietly through thick wooded swamps, without the slightest whisper of wind, or ruffle of leaf.
Owls, and other birds of prey, are often Keystone Species
Animals with such great hunting capabilities can have large impacts on an ecosystem. Robert Paine coined the term keystone species in 1969. According to Paine, Keystone species are animals that help manage other animal species by controlling population numbers and biodiversity within an ecosystem. The impacts of keystone species are usually greater than their numbers. For example, one owl can eat a large number of rodents and small mammals, with few animals preying on the owl in return. Because of this owls can be a great benefit to places where rodent populations are high. Dense urban areas often suffer from an abundance of rats and mice spreading disease, and rural agricultural communities have their crops consumed and soil eroded from burrowing voles and field mice. Without owls, and other top predators, rodent populations could explode and exacerbate the effects they produce.
Trophic Cascade is a term used to describe the snowballing environmental effects of losing or gaining apex predators. In 2015, National Geographic featured a nice piece on how the reintroduction of wolves into Yellowstone National Park created a trophic cascade, affecting populations of prey animals so much that it eventually changes the course of a river. But not all predators have four legs and teeth. Some have human sized wingspans, and dagger like talons. Having healthy predators may not seem like good knews to animals small enough to be an owl lunch, but it is an indicator of a balanced ecosystem. It means that the animals lower on the food chain are plentiful and healthy enough to support the physical health of the predator. If the owls of a swamp are healthy and plentiful, it is fairly safe to assume everything happening within the food chain below is normal. But if the owls begin to develop illnesses, or decline in numbers, it is equally safe to assume that something significant has changed somewhere in the relationships below it.
Where to find owls
There are many species of owls that live in close proximity to people. They may be hanging out in a local farmer’s barn loft, or in a tall tree on the edge of the city. Sometimes it is simply a matter of being around when owls are active, and keeping those eyes and ears open! Nature preserves and wildlife refuges are also fantastic places to get a view of these elusive avian creatures. In fact, the Barred Owl is so present along the Roanoke River that there is a camping platform along the Roanoke River Paddle Trail named ‘Barred Owl’s Roost’. It earned the nickname due to the large populations of these hooting hunters, and the evening chorus of owl calls that sing the sun to sleep at night. Luckily, with the exception of Antarctica, different kinds of owls can be found all over the world!
Want to help owls but not sure how? First, remember that owls have different habits than most birds. Being mostly nocturnal, owls need safe places to sleep during daylight hours. Also, speaking of nocturnality, owls hunt better in darkness. Reducing the amount of unnatural light will allow owls to do what they do best. It could be as simple as turning off the porch light as much as possible.
The next thing to remember is that owls are impacted by human development reducing the amount of hunting and nesting environments. You may not think something living in the trees would be impacted by what happens down below, but even if human development heavily impacts the environment of an owl’s prey, it can have detrimental impacts on the owls. Things like parking lots reduce the amount of woodland and pasture area that creates habitats for smaller animals such as rodents, a key part of an owls diet. Owls are also often hit by vehicles. They sort of have tunnel vision, and in the grass and ditches lining roads are good hunting grounds for rodents and small animals. Unfortunately they get are so focused on the prey that they sometimes don’t see vehicles, and are hit because of it.
Since owls eat rodents, not store bought foods made for small birds, attracting rodents with things like taller grass and brush piles can provide shelter for animals that owls hunt for. Maybe there are an abundance of rodents in your area already. If this is the case, avoid using rat poison against them. This can be ingested by anything that may eat the rodent, causing more problems throughout the food chain. If the rodents are indoors consider using traps instead. If the rodents are outdoors, an owl is the best pest control you will never have to buy. Leave them somewhere to sleep, somewhere to perch for hunting, and they will do all the dirty work!