How To Control House Sparrows

Food habits. These birds are primarily granivorous. Plant materials (grain, fruit, seeds and garden plants) make up 96 percent of the adult diet. The remainder is animal food. Feeding habits of nestlings are almost reversed in that they eat 68 percent animal matter and only 32 percent plant materials. In urban habitats, garbage, bread crumbs and refuse from fast-food restaurants can support stable sparrow populations.

General biology. Breeding can occur in any month but is most common from March through August. The male usually selects the nest site and controls a territory from there. The nests are bulky, roofed affairs, haphazardly built without the good workmanship of he other weaver finches, the group to which the house sparrow belongs. Sparrow pairs are loosely monogamous. Both sexes feed and take care of the young, though the female does most of the brooding. From three to seven eggs are laid, four to five being the average. Incubation takes 10 to 14 days and the young stay in the nest for about 15 days. They may still be fed by the adults for another two weeks after leaving the nest.

Sparrow are a very aggressive and social bird, successfully competing with most native birds. A sedentary species, they have no recognized migratory pattern. Studies have shown 90 percent of the adults will stay within a radius of 1-1/4 mile during the nesting period. Exceptions occur when the young move about setting up new territories. Also, when the young move about setting up new territories. Also, flocks of juveniles and non-breeding adults will move four to five miles from nesting sites into seasonal feeding areas.

Greatest mortality occurs during the first year of life. In the wild it is doubtful if sparrows surviving that first year live much past their fifth season (one bird lived in a zoo for 23 years). While the sparrow is very tolerant of disturbance by humans, it can in no way be considered tame. Its success lies in its great durability to exploit new habitats, particularly those influenced by humans.

Damage. One big source of economic loss to sparrows is their consumption of grains in fields and in storage. They also interfere with the production of livestock, particularly poultry, by consuming and polluting their feed. Because they live in such close association with man, they are a factor in the dissemination of diseases (chlamydiosis, erysipeloid, Newcastle, parathypoid, pullorum, salmonellosis, transmissable gastroenteritis, tuberculosis, various encephalitis viruses, vibriosis, and yersinosis), parasites (acariasis, coccidiosis, schistosomiasis, taeniasis, toxoplasmosis, and trichomoniasis), and insect pests (bedbugs, carpet beetles, clothes moths, chiggers, gypsy moths, as well as various fowl ticks, mites, fleas and lice).

In grain and other storages, fecal contamination probably results in a as much monetary loss as does the actual consumption of grain. Their droppings and feathers create a janitorial problem as well as hazardous, unsanitary and odoriferous situations on the inside and outside of buildings and sidewalks under roosting areas. Damage also can be caused by the pecking of rigid foam insulation inside buildings. The bulky, flammable nests of sparrows re potential fire hazards. The chattering of the flock on a roost is another form of annoyance to nearby humans.

Nestlings are fed largely on insects, some of them beneficial to man. Some are insects which prey on other insects economically harmful to man. This negative quality of the house sparrow’s diet is worsened because this bird competes with our native, and generally more insectivorous, birds. Martins and bluebirds, in particular, have been crowded out as sparrows gang up on solitary native species, driving them away and destroying their eggs and young. In competition for favored nest sites, the sparrows generally have been more successful.

Legal status. The house sparrow, because it is an introduced species, is afforded no legal protection by federal statutes. However, a few misguided states may offer them some protection by requiring permits or otherwise restricting control activities. Methods of control are apt to be regulated by state or local governments, so it is necessary to check these before poisoning and shooting.

Damage prevention and control. PCOs have a number of options available when designing a control program for these birds, including:

• Exclusion. To exclude house sparrows from buildings, it is necessary to close all openings over ¾ inch. Broken windows in upper stories should have the glass replaced or be covered with a solid material like plywood or wire mesh. Large openings, like bell towers, should be blocked off with poultry mesh no bigger than ¾ inch. Warehouse doorways that must accommodate human traffic can sometimes be effectively blocked to sparrows by hanging plastic strips clear to the ground in front of the opening. These will not seriously impede human movements yet present an impassable barriers to the eye of the sparrow.

Signs should be attached flat against buildings so as not to provide roosting space. Otherwise spaces between the signs and the building should be screened or otherwise blocked off. Ledges such as those under shopping mall overhangs or on old buildings should be fitted with slanted metal or wooden boards (45 degree angle or greater) so the birds cannot roost or nest on them. Eaves should be screened if the birds are able to squeeze into them. Spaces between window air conditioners and the building should be blocked off. It is possible to place fine mesh over the gingerbread architecture on old buildings to prevent roosting. It is much more effective, however, to work with architects on building designs that eliminate ornamental patterns and holes that provide new spots for sparrows.

Sparrows can be kept from roosting on ivy-covered walls by stringing plastic bird netting (green or black) over the vines. While not as satisfactory as removing the shrubbery, the mesh generally blends in with the plants and still prevents the birds from roosting and nesting in them. Mesh behind ventilators will keep birds out of a building, but often does not prevent sparrows from crowding their nests into the ventilator slits. Netting should be placed in front of the ventilator openings. Construction of ventilators, vents, air conditioners, building signs, ledges, eaves, overhangs, ornate designs, etc. should be examined insofar as practical.

It is difficult for homeowners to discourage sparrow competition with more desirable native birds. Bird feeders can be wired electrically to give unwanted freeloaders a "hot foot" when they land on the feeder. This requires watching the feeder so the current can be activated only when sparrows are attempting to feed.

Sparrows cannot use bird houses with openings of 1-1/8 inch or less, as this size can e used only by wrens. A big boon to sparrow production has been martin apartment houses. Sparrows which move into an area first will soon preempt the martins. PCOs should urge homeowners to place martin houses on tall poles with the uncluttered air space necessary for their aerial acrobatics. It must be possible to lower and clean the houses at the end of the breeding season. The entrances should be blocked until martin scouts appear back from their winter feeding grounds. It has been suggested that nest boxes with 1-1/2 inch entrance holes and 3-1/2 inch hole bored in the roof, covered with 1/2inch mesh, will encourage bluejay nesting. Bluejays apparently can withstand wetting, but the sparrows like a tight roof.

• Cultural methods. Destruction of roosting sites is one approach to a sparrow problem. Total removal of shrubs or even trees is an effective but extreme measure. Frequent removal of dead fronds from palm trees also will eliminate roosting sites.

• Repellents. Repellents are another option for PCOs when designing a control program for sparrows. The more common repellents include:

Acoustical. No truly successful alarm or distress noes have been found for the sparrow. The use of alarm notes designed for other species, as well as disturbing noises like fireworks, exploding shotgun shells, automatic acetylene exploders and cymbals, will move sparrows from an area for a sort initial period. But sparrows adapt quickly to the eccentricities of humans and will not be repelled by sounds for any great length of time unless the sounds are diversified and their locations shifted constantly.

Gustatory. Not much research has been done on the sparrow’s sense of taste, but it appears to be very rudimentary.

Olfactory. As in the case of the gustatory sense, not much is known about sparrow reactions to odors. Napthalene is registered for use in driving sparrows, other birds and some mammals out of enclosed spaces, like attics. Drawbacks are that the chemical must be applied at high rates and generally must be renewed frequently. The odors can drift down to cause discomfort to humans living below.

Tactile. Examples of this type of repellent are the sticky bird glues spread on ledges to prevent roosting. These polyethylenes and polybutylenes are reasonably effective for periods of a year or more. They are messy and should be placed on taped or sealed masonry surfaces so they can be removed. In time, they become hardened by changing weather and covered with dirt and grime, subsequently losing their tackiness.

A more expensive repellent, but one that lasts longer than chemicals are "porcupine wires," such as Nixalite and Cat Claw. These stick up at angles so the birds cannot roost comfortably on an area. Ledges and other niches must e completely covered for this method to e successful. Sparrows can roost on ledges on ½ inch wide. Stringing wires that give off intermittent electrostatic charges among the roosting sites is an expensive alternative, but it has been very effective.

Visual. As in the case of acoustical repellents, visual repellents generally are of limited effectiveness. They can be helpful in some areas where rain is susceptible to damage for only a short period. Of the "scarecrow" devices, those that move about and simulate birds of prey - such as hawks - are most successful. Also the birds can be frightened by novelty devices such as shimmering foil strips. The most effective approach is intermingling and alternating the use of several control measures repellent to birds both acoustically and visually.

Toxicants. For best results with toxicants, the birds must be prebaited with untreated bait materials of the same type to be used with the toxicant. Bait several spots a few yards apart. Prebaiting must be carried on from several days up to two weeks before applying the toxicant. The best baiting sites are flat ground or rooftops where the birds normally congregate. V-shaped troughs can be used several feet off the ground to minimize attraction for some other species.

Poison bait can be rotated around in the various prebait locations for a couple of days, replacing toxic bait with clean grain in the cycle. Dead birds should be picked up frequently to reduce the psychological effect on the remainder of the flock.

As bait preferences vary with geographical locations, it is advisable to conduct tests of candidate bait materials to find which are the most attractive in a particular area. The grains to be tested might include cracked corn, wheat, barley, milo, millet, oats, rice, higera, canary seed and rape. A large grain like corn must be cracked. The most attractive sizes of cracked corn lie between 1/16 - 3/16-inch. A cracked grain is preferable because it can be made to a more digestible and attractive size. Furthermore, the toxicant is place directly on the edible part of the grain rather than on the hull, which the bird might crack and discard along with the toxicant.

The writer has had success in one instance by placing poisoned grain in he first and second story ledges in a city. Sparrows, unlike starlings, will feed on roosting sites if given the opportunity. This created an area repellency for a time, which was one of the objectives of the project.

4-Aminopyridine (Avitrol) is registered as an area repellent as it causes the affected birds to react so violently the remainder of the flock is frightened out of the treated area. However, most of the affected individuals eventually die. Usually large numbers of sparrows die before the repellent effect is achieved.

Fenthion and endrin can be used in toxic commercial perches (Rid-A-Bird). Though endrin has a slightly higher toxicity for sparrows, fenthion is often preferred because of its specificity and lower residual danger. These metal, artificial roosts have a wick in the center that delivers the liquid toxicant to the feet of the bird as it perches on the roost. This is an effective and reasonably selective method when used inside buildings, provided that extreme care is taken to reduce spillage of the toxicant and the applicators are well aware of the hazards of the toxicity of these chemicals to their skin. The habits of the birds in individual situations must be studied to determine the most effective placement of the perches.

Since state pesticide registrations vary, check with your local extension service office for information on toxicants and repellents legal in our area.

Fumigants. There are no fumigants registered for use against sparrows, but some success has been obtained with carbon monoxide and ammonia gases in interior situations. (Caution: Toxic gases should be handled only by those technicians trained in their proper application and wearing suitable protective equipment.)

• Traps. Probably the most widely used method in attempting to reduce sparrow populations around a given area is rapping. As most bird traps normally are live traps, non-target species can be released unharmed. This method rarely violates regulations. There are more types of traps available for sparrows than for any other bird. Offsetting the advantages of trapping is the fact that a sparrow that has been trapped once rarely will be retrapped. Despite their willingness to associate with humans, sparrows’ suspicious nature and high intelligence level (for birds) makes it difficult for traps alone to remove a sparrow population completely from a given area.

Trap types can be classified in the following manner:

Funnel traps. These are the most commonly used types available. While they are probably the most easily entered of any trap, sparrows can also escape from them with comparative ease. Thus they should be checked frequently, and the birds removed. Where possible, decoy individuals should be safely penned in separate compartments inside these traps.

Automatic traps. These are counterbalanced multicatch traps. The birds enter a compartment from which there is no escape. The decoy compartment then moves back into place ready for another victim. It is a little more difficult to entice the birds into this type of trap than the funnel traps, but the final catch is probably greater as it is almost impossible for the sparrows to escape.

Triggered traps. This type is limited y the number it can catch at one time. In some cases they are not automatic and consequently require a watcher to tend the traps and spring them at the proper moment. the "clap trap" is one of the oldest bird traps, used first by ancient Egyptians.

Mist nets. A final method of trapping is to entangled flying birds in a fine net known as a mist net. The net traps are placed across flight lines of the birds in front of a dark background. The nets cannot be seen until the birds blunder into them, become entangled and are unable to extricate themselves. Mist nets also require a considerable amount of handling and are illegal in some states.

• Shooting. Where local ordinances permit, shooting with air guns or low-powered firearms can be used with some success. The birds quickly become wary of a human holding anything resembling a firearm, so shooting from a blind is recommended whenever possible. A old method is to place grain in a window and blast with an open choke shotgun into the flock baited into the line of fire. Special ammunition in the form of "dust shot" (No. 10 shot crammed into a .22 long rifle shell) or "BB" caps (lead slug in a short .22 shell) is available. However, the effective range of these specialized tools is extremely limited.

Other methods. A number of other control options are available to PCOs. These include:

Chemosterilants. Chemicals designed to interfere with the reproductive capabilities of the species are slow in action but acceptable to sensitive persons who are upset at killing birds directly. Some birds are always left and recruitment of new birds is a constant threat in attractive sparrow habitats. While experimental evidence indicates 20,25 diazacholesterol dihydrochloride (Ornitrol) will work against sparrows, this chemical is registered as a bait only for pigeons.

Detergents. A method as been registered to kill blackbirds and starlings on a roost by spraying them with a wetting agent (PA-14). This destroys insulation of the feathers, stressing the birds, which then die of exposure. The method has also been used against sparrows, but it requires specific environmental conditions (temperatures below 40 degrees F/4 degrees C) ad a 90 percent probability of at least 3/8 inch of precipitation within 24 hours of the spray application. Use of this method also requires the approval of the U.S. Fish and Wildlife Service.

Narcochemicals. These chemicals make the birds lethargic. They inhibit muscular response to stimuli so the birds can be captured by hand. Heavy overdoses can kill. Bird deaths also create an area repellency in the birds recovering from the effects. There are no chemicals registered for this purpose in this country, but narcochemicals have been used the world over from grain soaked in saki in Japan to alpha-chloralose and tribromoethanol in Europe.

Nest destruction. Where the can be reached, pulling down nests and destroying the eggs and/or young in them will discourage sparrows from using an area. As they are persistent birds, this operation must be repeated at two-week intervals throughout the breeding season. In stock barns where nests were too high to get to easily, oil was sprayed on nests since the mess made by the spray was not objectionable. Nest destruction is also recommended in sipping malls and around building signs in urban areas. The nesting materials should be collected and removed to make it harder for the birds to find material for new nests.

___ William D. Fitzwater