By: Larry Pinto
House sparrows can be difficult birds to control, in part because of their high reproductive capacity. A female house sparrow averages three to five broods per year with four to seven eggs per brood. In other words, she can generate about 25 young per year. Such population growth can quickly repopulate an area with replacement sparrows after a poisoning, shooting or trapping program.
Their small size makes it difficult to “sparrow-proof” a structure completely. Repelling them with spikes, wires or sticky repellents can also prove difficult because sparrows can squeeze into much smaller spaces than can pigeons or starlings.
House sparrows are experts at exploiting human habitats in cities. They nest inside vents, gutters, signs, traffic lights, billboards, malls, box stores, airports, warehouses and other structures. Large populations can feed quite well on scraps of food left by people in parks, fast-food parking lots, picnic tables or overflowing trash containers. Whenever food or garbage is spilled or discarded, it provides a banquet for house sparrows within a one-mile radius.
Two of the more common and troublesome sparrow problems faced by PMPs are:
- sparrows living inside a building, such as a food plant, warehouse, box store, mall or atrium; and
- sparrows nesting on three-dimensional storefront signs.
There are various bird control tools whose salesmen claim work just fine against sparrows. But sparrow management, as with all bird work, is as much art as science, so what doesn’t work in one instance may work well in others. Here are the methods I have seen work effectively against the two common problems described above.
INSIDE A BUILDING
When sparrows are found inside a building, you can assume a number of things:
1. They have found adequate supplies of food and water.
2. They have established regular perching locations, flyways and nesting areas.
3. Most important for your future business, new birds will find their way inside just as the first birds did.
This last point provides you with two potential sources of additional business. If the building requires birdproofing (typically netting) to prevent reinfestation, you have the inside track because you are already doing bird work at the account.
If access to the building cannot be eliminated — for example, if the birds are entering through automatic doors (such as in a box store) or loading dock doors — additional bird removal services will be necessary on a regular basis.
Repeat business is always good. Just be sure to make clear at your initial proposal that the problem will likely reoccur, so that new bird invasions do not come as a surprise.
I recommend these options for removing birds from a building:
- Mist nets — These fine-mesh nets trap birds alive by entangling them. They are typically 7 to 8 feet high and 30 to 40 feet long, and contain pouches into which the birds fall. A mist net is placed loosely across a flight path in front of a dark background. The birds fly into (or are sometimes driven into) the net because they cannot see it and are captured.
If there are lots of birds in the account, the first sparrows trapped will be noticed by those remaining, who will become wary of the area. You may need to move the net around or use multiple ones to cover an area completely.
There are problems with mist nets. They cannot be left unattended. Captured birds have to be removed immediately. The nets cannot be used outside without a federal permit because they could capture migratory, threatened and/or endangered birds. Some states prohibit their use, although those rules may or may not apply to indoor private property.
- Sparrow traps — There are many different types of these traps available. Their effectiveness varies greatly and often depends on the skill of the trapper. House sparrows quickly become trap-shy, and it can be difficult to trap all birds at a site. Saturation trapping is your best bet. Set out a bunch of traps baited and unset (or propped open) for a week until the birds become acclimated. Then set them all at once to trap as many birds as possible before the remainder become wary.
- Shooting — This is often the last resort for the last few sparrows inside a building. Air guns are most commonly used because of their accuracy and the reduced risk of collateral damage. Other options include .22 caliber dust shot or BB caps.
There are major limitations to shooting sparrows inside a building. Local ordinances may prohibit the use of firearms or the killing of sparrows, and some people may decry such lethal control of sparrows (see “Major pest or friendly chatterbox?” page 101 of this issue). You and your client may not want to risk the bad public relations.
House sparrows seem to love to nest on and inside signs over stores, hotels and other businesses. These signs provide many suitable, protected sparrow nest sites because of their intricacy. An added problem is that customers do not want their signs defaced by visible bird control tools.
Some signs are best “sparrow-proofed” by being netting entirely. This works best where the sign is high above the ground so the netting becomes invisible. The netting must be installed perfectly, though, to keep out sparrows because they seem to be able to squeeze their way through the least opening from a poor installation.
Bird shock repellers have improved significantly in recent years and can keep house sparrows from nesting on many types of signs. If you haven’t used a shock system lately, be sure to check them out. They have become more effective and dependable. Some repellers are powered by solar cells. Many signs have 110-volt outlets or boxes as part of their system, however, which can be easily accessed to power the bird shock system.
There are wire systems and track systems. Be aware that for sparrows, the wires need to be close enough together so that the sparrows can’t avoid them, yet far enough apart to prevent arcing. On most signs, you can anticipate the prime areas that sparrows will first land on. These sites are most critical for proper installation. Again, the best installations will depend as much on art and experience as on science.