Birds Can Be Pests
In most respects birds in nature and in our landscape are highly beneficial and highly desirable, but as with nearly all groups of animals there are bad apples in the bird world too. Some of the worst offenders in the bird world are those which have found their way into North America from other parts of the world, due to human activities which transported them outside of their "natural" habitats. When a bird, or any other living organism, has lived in a geographic region for perhaps millions of years, that habitat adapts to allow that organism to blend in. It does not overwhelm the other organisms around it with its presence, and we generally refer to this situation as a "balance" in nature. Things can happen that upset that balance, hopefully temporarily, but for the most part live rolls along smoothly.
As humans increased their travel from continent to continent in centuries past they became the means for living things - plants and animals - to quickly move to new locations. Often it was a deliberate effort by emigrants who were moving permanently to new homes in a new land, and they took along many of the things they felt they would need for survival there. This often was seeds, grains, or plants for their gardens, their food, for their livestock, or other uses, and the plant life in North America changed dramatically. Birds were also moved from Europe to North America by people who did not understand the potential impact that exotic invader could have in a part of the world where it did not belong. Three of the birds that cause us the greatest problems now are among these immigrants, and these are the Pigeon, the Starling, and the English Sparrow.
It may come as a shock to many people to hear that these three species of birds are foreign invaders, since they have been in the U.S. for so long, are so common, and are so widespread. This, however, is one testament to their invasive behavior. Starlings were introduced in 1890, as one species in a group of birds from Europe that were deliberately released into New York's Central Park. The pigeon was already domesticated and used for food, sport, or other human uses thousands of years ago, and brought into North America in the 1600's for those uses. The English Sparrow, also called the House Sparrow, is another native of Europe and Asia that was brought to the U.S. and deliberately released. It seems to prefer living close to human activity, and commonly will make its nests in or on our structures. By their feeding and nesting habits these birds may compete with other, native birds, and in this way can pose a threat to the natural order of wildlife in North America.
However, birds can also be a threat to people and our property, and we can sum up the reason for that in a single word……feces. The droppings of birds are a perfect growth medium for a large number of bacteria, viruses, and fungi that may be pathogenic to people. When we have accumulations of pigeon droppings in attics, on patios, or roofs or ledges, we also may have these kinds of disease organisms there as well, and if the fecal material dries and becomes airborne we stand a greater chance of inhaling a problem. Some of the serious diseases associated with bird droppings include histoplasmosis, candidiasis, cryptococcosis, toxoplasmosis, and others. Bird fecal matter also commonly harbors Salmonella, and when the droppings end up in water that is consumed by people this serious food infection can result. Dozens more pathogens of bacteria, protozoa, viruses, and fungi are also associated with them. Birds also are home to many arthropod parasites, such as bird mites and bird bedbugs, and when these birds live in close association with people they commonly introduce those biting mites and bugs into the building. All of these problems are not unique to these three kinds of birds, but because of their numbers and their close association with people and our homes these birds often pose the greatest health threat to us.
The purpose of this article is not to cause us to fear or dislike birds, but to understand that there may be drawbacks to allowing them to live in and on our homes. Well managed birds, such as racing or homing pigeons kept by hobbyists, are likely to be well maintained without parasites, and in their own cages where they do not bother people. It is the "feral" pigeons that now live in semi-wild flocks that pose the problems.
Beyond the potential health threats they pose, we all have seen the disgusting mess they can make on the ground or other surfaces below their nests. It is not unreasonable to suggest that it is more appropriate to encourage birds to create their nests someplace other than under the eaves of our home, in the attic, or on ledges we provide around patio covers and other horizontal surfaces.
One important thought here, though, is with respect to swallows, which create their nests from mud and absolutely love to place those nests under the eaves of structures. It is common to find private homes with solid lines of these mud nests along several sides of the house, with hundreds of swallows now taking up residence where people also live. Swallows are protected birds, and you cannot harm them and you cannot disturb their nest once it is established and completed, since by that time there could be eggs or young birds in that nest. Once the nest is completed you must, by law, allow them to complete their cycle of raising their young, and only after the young birds have finally left can you remove the mud nests. Since you may not want these nests on your home you have two options. The first is to discourage the nest building at the moment the adult birds begin it, by scraping or washing the beginnings of that nest off immediately, in the hope that the birds finally go somewhere else.
The second option is to prevent access to the nest sites by the birds, and for this you may want to work with a licensed pest management company that has experience in doing bird control work. There are many physical materials that can be installed on homes that will keep the bird from having access to the places they want to roost or nest. For swallows this may be plastic netting, installed in such a manner that it does not detract from the appearance of the home, lasts for many years, and causes no harm or distress to the birds. The same kind of netting may be perfect for closing off areas that pigeons are going to. You can often find large retail stores which have had this netting installed overhead, eliminating the ability of birds such as sparrows to roost on overhead pipes, beams, or equipment, and from these roosts depositing their rather unsanitary droppings down onto the merchandise (or customers) below.
Other physical devices that are highly effective at bird exclusion include plastic or wire pronged strips, permanently attached to horizontal ledges so that birds can no longer land on the ledge. The professional may also use stainless steel wire, strung tightly along ledges and raised several inches off the surface, once again to prevent the bird from using that ledge. There are a number of other ingenious devices that are very effective and yet pose no hazard to birds that may contact them. The goal should not be to kill the birds, for that would be a very temporary solution anyhow. If your home is attractive to the first group of birds it will continue to be attractive as long as other birds can find their way onto it. Physical exclusion of the birds is your best long-term solution, including ensuring that attic vents are in good condition to prevent birds from entering this enclosed area. This kind of good building maintenance will also prevent the entry of other unwanted animals, such as bats, squirrels, or rats.
What does NOT work for keeping pest birds away from your home? Well, tops on the list would have to be ultrasonic repelling devices, even though many of these magic boxes claim to repel all manner of "vermin", from bats to birds to bugs to snakes. A great many independent university tests of ultrasonic repelling devices consistently show they have no effect. Insects, according to experts on this, are incapable of even detecting ultrasonic sound, so it seems logical they would not be affected by it. Birds or rodents might detect the sounds emitted by these devices, and possibly be agitated temporarily. But, experience shows they quickly become accustomed to it and ignore the irritation. In fact, it is not uncommon to find birds nesting directly behind ultrasonic repelling boxes that seem to be functioning as they should.
Many frightening devices are also available, and these may or may not have some effect on unwanted birds. These include scare-eyes, flickering tapes, flashing lights, or plastic predators such as hawks or owls. Again, something new placed in the environment of a nervous, cautious bird may cause the bird to leave an area, but if nothing happens the birds often become accustomed to it and will return. For the best results you would need to move the device regularly so that it appears to be in different places. Again, there are pictures available showing pest birds sitting on the head of a plastic owl, so these materials are not always effective.
The cost for installing exclusion materials will be higher than the simple placement of something that may scare a bird away, but these materials are going to give a much greater guarantee of success and for a much longer period of time. They do not harm the birds, but simply make it impossible for them to find a way to get to the areas they look for to nest or roost. By making it inconvenient the birds will look for another place that does not cause them such difficulties, and you can live in a home that is not covered with accumulations of fecal material.