- Sharron Montgomery Pena
We Put the Prey in Bird of Prey
often like to pose a question to groups of children about why owls are found on every continent but Antartica? It’s cold. Yes, that’s true it's cold, but they have a layer of down to insulate them against extreme temperatures. There’s no trees. Yes, that’s true there’s no trees, but owls can be found in urban environments and will sometimes build their nests in the eaves of houses, and in abandoned structures. Trees are not something that owls need to survive. There is often silence after this. While it may be inherently obvious from the title of this article, it’s not always on the minds of people in the midst of a bird of prey program. Birds of prey need prey, otherwise known as food, aka something to eat. Antarctica is a hostile environment to say the least, and without a steady food source, rodents and other smaller creatures have a hard time eeking by to say the very least.
Although birds of prey tend to be opportunistic and will take whatever prey is available, rodents are always on the menu primarily mostly because of their sheer numbers. Rodents comprise the largest group (or order) within the class mammals. There are over 2000 different species of rodents worldwide or over 40% of all mammals. In the United States the most widespread rodents are usually mice and rats, and to a lesser degree squirrels, prairie dogs, and groundhogs. For the purposes of this article I will focus mainly on rats and mice as prey and why birds of prey are so important in controlling their populations.
On average, mice reach breeding age at 6 weeks and are able to give birth to 4-12 young per litter. Rats only take slightly longer reaching breeding age at 9 weeks and giving birth to between 5-10 young. It is easy to see how quickly a rodent population can grow and why a healthy population of predators is essential to their control.
Over and over it has been shown that barn owls are much more effective in controlling mouse populations in agricultural environments than rodenticides (poisons). In a study from 2011, eighteen barn owl pairs nesting in man made boxes in a 100 acre vineyard consumed an estimated 25,000 mice, delivering a substantial savings of almost $8.00 per mouse as compared to the hiring of a pest control service and the use of toxic rodenticides. Read the article here.
Likewise, the use of poisons to control rodent populations is largely unsuccessful and only results in the consumer becoming dependent on an industry that provides only a temporary solution while causing secondary poisoning of other animals including precious pets.
When I was a wildlife rehabilitator, I treated many raptors that were on the verge of death because they were able to catch a poisoned rodent. These rodents become easy prey because they often stagger about slowly attracting the attention of predators and become quickly consumed.
Exploding populations of rodents are almost always related to a lack of predator/prey relationship as well as the creation of feeding and foraging opportunities for rodents in human environments. Wherever there are humans, there is certainly always garbage which becomes a good food source for scavenging rodents. Once rodents have found a reliable food source, they will almost certainly decide to set up housekeeping close to that food source, raise a family, and so on and so on, get the picture?
The annoyance of rodents can be seasonally problematic. When I lived in South Florida, when the fruit trees were heavy with fruit, I rarely even SAW a rodent. One year, however in the winter, I trapped around 20 rats in the course of a couple of months in my small one room apartment. They had found their way inside, chewed a hole through my plastic dog food storage bin and decided to stay. After I began trapping them and storing all of my food out of reach they disappeared. Just a few small changes and efforts and I was able to solve my rat problem.
Here at our property in North Florida, the mice start to come inside in the winter months, but then all of a sudden once we start trapping them, they all of a sudden stop. They are never a problem in the summertime, because there is plenty for them to eat outside. There is also a healthy snake population that is active in my yard in the summer, something worth bearing in mind should you feel the need to kill any snake you should see. So we have learned the cycle and rather than jump to drastic measures, we try to increase our efforts to keep them under control during peak times, rather than trying to wipe them out and several unfortunate predators as well.
And before we go, a word about squirrels. People either love them or they hate them. For me, to watch a pair of squirrels chasing each other around and around a tree is a delight similar to watching children chase each other. To some however, squirrels are a nuisance taking over their bird feeder, spilling the seed everywhere, and bullying the birds until they give up to forage elsewhere. I would even say some people get boiling mad. Most likely, there is a lack of predators to keep the squirrels in check. In addition, squirrels have (rather smartly I might point out) figured out in the same way that rats and mice have, that where there are people, there is free food. And let's think about this for a moment. If I’m a squirrel, should I go out foraging over 10 or 20 acres to find acorns, nuts and other seeds, or should I hang out at the bird feeder at the “all you can eat” buffet of premium bird feed and spend the rest of the day sleeping in my nest or hole until I feel the need to get up and eat again? Hmmm. Are humans creating the problems? Yes. But we have the ability to change the situation by changing our behavior. Stop feeding the animals if you don’t like the result. They will eventually move on to forage elsewhere. They will not starve I promise. It also concentrates the animals in one place rather than distributing them. Their buried and forgotten acorns and nuts will become trees helping to repopulate the few wild stretches of habitat supporting our fragile populations of wildlife.
Birds of prey are one of nature's most perfect “pest control” systems. They have an infinite amount of patience and will wait and watch until that unsuspecting squirrel, or mouse comes across their path so that they can seize an opportunity for a meal. Allow them to do their job and keep the rodent populations under control. It saves money, it saves lives, and most of all preserves the balance of nature the way it was intended to be. For more information about non toxic methods of discouraging rodents and other wildlife, go here to visit a great resource from the Hungry Owl Project.