Taking The "Nuisance" Out Of Nuisance Sparrows

In addition to the pigeon, the common English sparrow (Passer domesticus) is among our most numerous and annoying urban bird pests. It can also be among our most frustrating pests to control. But it need not be. Let’s briefly examine the factors that contribute to the sparrow’s persistence in urban environments and the methods of managing this bird.

SPARROW HABITS. Under the right conditions, the house sparrow can reproduce quickly. Nest building and egg laying begin in March and April in the northern United States, and slightly earlier in the southern states. The clutch contains between three and nine eggs, which hatch in only 11 to 17 days. The young are fledged about 14 days later. When conditions are favorable, the sparrow can produce up to five broods per year. In the temperate regions of the country, this reproductive capacity is offset by high natural mortality rates of 40% to 60%, determined primarily by harsh winters.

In our cities and towns, the sparrow takes advantage of the feeding behaviors of people. Thus, the sparrow has little difficulty in finding scraps of food left around parks, picnic tables, fast food stands, market places and similar locales. Unkempt city garbage containers and commercial dumpsters can be especially conducive to promoting sparrow infestations in the buildings nearby the refuse containers. During the spring and summer, the sparrow supplements its human foods diet with various insects, an important protein source needed for reproduction.

House sparrows are group-loving birds that nest, roost and feed together in flocks. The sparrow does not migrate, and the home ranges are small. Most of the bird’s daily activities occur within only one to two miles of the nest. This behavior is important in control operations because where it is possible to eliminate a resident population, re-infestation by immigrant sparrows is slow.

The sparrow is especially adept at locating nooks, crannies, ledges and corners around our structures and equipment to construct its nests. Various types of vegetation, weed stems, twigs and man-made materials such as paper, string and cardboard are used to build a crude and messy nest. The nests are often situated in gutters, on roofs, building ledges, loading docks, inside buildings on roof supports and within commercial billboards and electronic signs. In nature, the sparrow nests in trees and shrubs repeatedly using the same nesting holes throughout several generations.

SPARROW MANAGEMENT. Relative to many other urban pests, managing sparrows is not especially difficult. There are several low-impact, non-chemical approaches effective for long-term management of urban sparrow infestations.

Because the sparrow is so prolific, control efforts are best begun when there are only a few birds. Allowing a few sparrows to remain around the premises during the early spring can result in a significant infestation by summer’s end. Too, most bird control techniques have their greatest cost-effectiveness with minor infestation levels.

The high natural mortality rate of sparrows in the temperate regions of the country can be used to our advantage. Regularly removing sparrow nests from building areas can significantly reduce a local population over time. This is especially important during the spring peak-breeding season. Nests and eggs (states permitting) should be located and destroyed at 10- to 14-day intervals. Nests can be removed using long hook-poles or with water jets. The nests and all nesting materials must be totally discarded, thus forcing the sparrow to build a nest from scratch.

Sparrows may be persistent in using the same building sites for nests for long periods, but usually after only one or two nest removals the female sparrow vacates the area in search of less disturbed areas. Nest destruction efforts can be particularly appropriate for shopping malls, food plants, building signs and other areas where it is difficult to completely eliminate the food source.

Sparrows are attracted to shadowy corner areas where walls meet tight nooks and crannies, as well as many other covered areas that offer protection from the elements and enemies. Inspecting for such areas will aid in quickly locating and removing sparrow nests or for modifying these areas to deny the sparrows good harborage.

There are several habitat modification programs that can be considered. Vegetation growing close to or on the sides of buildings such as vines or ivy can be pruned or removed. Pruning out the dead fronds of palm trees will reduce roosting sites. Tight spaces behind commercial signs and utility equipment (e.g. spaces beneath window air conditioners) should be eliminated with netting or screening. Also, building ventilators should be netted or screened to prevent birds from crowding their nests into ventilator slits. And loading dock canopies and other commercial areas attractive to sparrows can be bird-proofed with plastic netting. Careful planning, using the right tools and accessories, as well as paying critical attention to details are all vital when installing nets. Incorrect or sloppy net installations are worse than no control program at all.

Sparrows can be denied from using and defacing building ledges with one or more of several ledge denial repellents. These include mechanical spikes, wires or sloppy net installations are worse than no control program at all.

Sparrows can be denied from using and defacing building ledges with one or more of several different ledge denial repellents. These include mechanical spikes, wires and chemical repellents. When using these tools, the key to long term results, and thus cost effectiveness, is a careful and thorough installation. Installers should also closely follow the manufacturer’s directions. The small sparrow is quite adept at roosting on ledges only ½ inch wide. They will take quick advantage of any gaps or small spaces left to them by ledge repellents on their favorite ledges. Additionally, the mechanical prickly repellent devices must be inspected periodically and cleaned of debris such as leaves and twigs. Otherwise, accumulating debris will protect sparrows from the prickly effect of the projections and they will continue to use the building area.

Worse, sparrows will sometimes nest directly on top of the accumulating debris. The mechanical ledge repellents and their installation can be expensive, but for areas under heavy bird pressure, the results justify the cost.

The sticky bird repellents (e.g. Hot Foot®, Roost No More® and others) are most appropriate for small- to medium-sized jobs and infestations where the mechanical repellents might be too cost prohibitive. They are also excellent tools for quick solutions until the client can implement a more permanent program. And they can be used to supplement the more permanent programs of netting and mechanical repellents.

Regardless, it is important to consider that most chemical repellents last for about one year. In areas of excessive heat, dust, or the food debris resulting from food production, gel repellents may only last for several weeks. Thus with the increasing costs of service time, the cost-benefit ratio of the temporary gels should be considered carefully.

So start early, and analyze the most cost-effective approach, while ensuring long-term control based on the client’s sparrow pressure. The profits in bird control are exceptionally good — providing attention is paid to the details.