Bluebirds Across Nebraska is providing this information on House Sparrow control to let you know that there are options available when dealing with sparrow problems. Given the widespread problems caused by House Sparrows, NABS advises that it is the responsibility of every nest box trail operator to ensure that no House Sparrows fledge from their boxes. It is better to have no nest box than to have one which fledges sparrows.
House Sparrows are the most abundant songbirds in North America and the most widely distributed birds on the planet. House Sparrows are not actually sparrows, but are Old World Weaver Finches, a family of birds noted for their ingenious nest-building abilities.
House Sparrows were introduced into North America from England in the 1850s on the mistaken premise that they would help reduce crop insect pests. At first, the new immigrants welcomed this little bird of their homeland. Within 25 years, however, they realized the seriousness of their mistake: the House Sparrow population had increased at an explosive and alarming rate, and the birds were causing extensive damage to crops and fruit trees. They were also taking over the nesting sites of native cavity-nesting birds.
Life And Habits
The breeding season for House Sparrows begins early in the spring or even in midwinter, and each pair may produce up to four broods a season. The male House Sparrow’s bond with his nest site is stronger than his bond with a mate he may lose a mate, but he won’t give up his nest site. Although they usually prefer to nest in a cavity, House Sparrows will settle for any nook or cranny they can find. They will also occasionally nest in coniferous trees and in the nests of Cliff Swallows and Northern Orioles.
The male constructs a bulky, dome-shaped nest of coarse grasses, weeds, hair, and feathers. The female lays three to five white/brown speckled eggs and incubates for 11-14 days. The young sparrows fledge after 14-16 days. They are not migratory, but flocks of birds move about within a 1.5-2mi. area. House Sparrows are primarily seed-eaters, although they eat some insects during the summer. They will also dine on garbage. Feedlots and farmsteads are particularly attractive to sparrows as they provide an abundant source of food, as well as shelter and plenty of nesting sites.
SPARROW CONTROL ON A BLUEBIRD TRAIL
Control of sparrows on a bluebird trail can be either PASSIVE (taking preventative measure when placing the box to deter sparrow use) or AGGRESSIVE (taking measures after the box is in place and sparrows are using it).
- Box Location—Box location is the most crucial factor in controlling sparrows on a bluebird trail. The House Sparrow’s Latin name, Passer domesticus, aptly describes its preferred nesting habits – around houses. Avoid placing boxes near farmsteads, feedlots, barns, old out-buildings, etc. Boxes placed in or around villages, towns or cities will likely be claimed by House Sparrows. If sparrows do take up residence, one option is to relocate the box to a site farther away from human occupation.
Sparrows may avoid a nesting site if the box is placed too low to the ground (3 to 5 feet). However, since boxes placed this low run the risk of being predated by raccoons, cats, or other climbing predators this is a feasible option where there are no climbing predators.
- Plugging The Entrance Hole— Plugging the entrance hole of a box taken over by sparrows will prevent the male from using that specific box, and might even encourage him to move elsewhere. Some bluebird trail operators plug the entrance hole at the end of the nesting season and leave it plugged until the bluebirds arrive in the spring. This will prevent sparrows from roosting in the box during the winter, and then staking an early claim in the spring.
- Use of Gilbertson PVC Boxes— Although Gilbertson PVC boxes are not 100% sparrow resistant, House Sparrows seem to be reluctant to use them. If PVC boxes are paired with a wooden box, sparrows tend to choose the wooden box. If you are trying to attract bluebirds in an area where you suspect sparrow problems, it might be wise to start off with the PVC box.
- Eliminating Feeding Areas, Roosting and Nesting Sites— Problems on a nest box trail can be reduced if the overall, local House Sparrow population can be reduced. This can be achieved by taking control measures at bird feeding stations (use of sparrow-proof feeders; avoiding cheap, mixed bird seed that contains a high percentage of filler grains, such as milo, millet or cracked corn; or use of monofilament line around seed feeders), as well as sealing up all potential winter roosting and summer nesting sites.
- Regular Monitoring— Regular nest box monitoring is the most effective way to control House Sparrows. If sparrow nests are regularly removed, no young will fledge from the box. However, the male will tenaciously defend his box, and will usually keep rebuilding his nest. He will also drive off any other bird that might express an interest in the box. Therefore, it is important to eliminate the male. This is usually accomplished using an in-box trap.
- In-Box Trapping— Two traps that work well are the basic Huber-style and the Gilbertson universal trap.
Do not set a in-box trap until a sparrow has laid claim to that box. Once he has claimed it, he will not allow any other species inside. The male sparrow will be more likely to enter the box if a small amount of nesting material is left in the bottom or tucked in the entrance hole. However, be careful that the nesting material does not interfere with the trap. The trap must be checked at least every two hours because there is the remote possibility that a bluebird or other native cavity-nester may have entered the box.
To remove a trapped House Sparrow from a box, place a clear garbage bag over the entire box and remove the trap with the bag still over the box. Once the trap is removed, the sparrow will fly into the bag. This is a much easier method than trying to reach into the box and catch the sparrow by hand.
Since House Sparrows are classified as pests and are not protected by federal law, they should be quickly and humanely dispatched as soon as they are captured. Do not consider relocating the bird, as this just relocates the problem. The dead sparrows can be frozen and given to raptor recovery centers to feed their injured raptors.
There are several ways to trap a large number of birds
- Ground Traps: These traps are easy to construct, and can hold a large number of birds. Approximately 10 birds should be kept in the cage trap at all times to act as decoys. These decoys can be attracted into the trap by baiting them with white feathers, grain, bread scraps, white proso millet, mixed bird seed or cracked corn in it. A small mirror placed in the bait compartment of the trap helps to lure the sparrow in. Food, water, and shelter must be provided at all times. Since sparrows are gregarious, the success of cage traps depends on the birds being attracted to the food and to each other. For this reason, the trap works least effectively in areas with a high initial population. Used continuously once the population is under control, its effectiveness, though varied throughout the course of the year, is usually consistent. These traps are especially effective during the winter, and when juvenile birds are abundant in mid summer.
- Cage Traps: Basically, these consist of nest boxes atop a wire cage. The nest box has as hinged floor, which tips the bird down into the cage below.
- Drop Traps: which simply drop down over a flock of feeding sparrows, can also be used once the sparrows are coming into an area regularly to feed.
- The Cedar Valley Live Trap: This is a repeatable trap that has a small “catcher” area that opens through a one-way trap door to a large holding pen. This permits the capture of a large number of birds.
IMPORTANT: All multi-bird traps must be checked daily to ensure that the trapped sparrows have adequate food, water, and shelter, and in case a native sparrow or other songbird becomes trapped. Native birds should be released immediately. The male House Sparrow is very easy to identify, but the females are quite similar to some species of native sparrows. Check a bird book if necessary.