[VERTEBRATE PESTS] Managing Crows, Part II

The management of crows in urban areas can be accomplished via several approaches. Sometimes, crows react quickly to a particular management program. But if a crow population has become habituated to people and city noises and disturbances, they may have lost their wariness and may require several attempts using different techniques.

It is important to first note that although crows can pose an annoying presence in a community, all species of crows are protected by the Migratory Bird Treaty Act. However, under this act, crows may be controlled without a federal permit when found "committing or about to commit depredations upon ornamental or shade trees, agricultural crops, livestock or wildlife or when concentrated in such numbers and manner to constitute a health hazard or other nuisance."

Although this wording grants a fair amount of flexibility in crow management from a federal level, every pest management professional must also check with their state and local wildlife officials to confirm whether or not crows are protected on a local level or what types of crow management approaches might be prohibited or restricted.

The following management techniques are those recommended for the more typical crow problems and roosts in and around residential neighborhoods, office buildings, food-serving establishments, schools, car lots, local parks and other areas where a pest management professional is likely to be called upon for assistance.

SANITATION. As with nearly every other pest group, the truism "sanitation is pest control" is also applicable to crow management. As discussed in Part I of this column last month, crows are intelligent birds and quickly learn which parts of town offer a daily and easily accessible snack of human food discards. This is particularly important relative to commercial trash bin areas and parking lots of supermarkets, convenience stores, gas stations and the giant mart-style stores. These areas must be kept clean on a daily basis to prevent the conditioning of the crows (and pigeons and sparrows) to linger on the property waiting for a "food scrap opportunity." Commercial property managers should be informed by the servicing professional that, regardless of the techniques employed, it can be particularly difficult to persuade crows to evacuate an area if food is readily available each day.

VISUAL REPELLENTS. For many crow problems around buildings, visual repellents offer a highly practical approach for managing crows that seem to be lingering around parking lots or building exteriors. Many visual repellents have been tried over the years, some proving more successful than others. Among the most effective are different types of metallic looking balloons, tapes and streamers. It seems the more metallic they appear, the better it seems to perform against crows. Examples include ordinary metallic "birthday" balloons, Mylar tape and the fringed streamers commonly seen strung about on various gala events. When crows are a problem in downtown commercial sectors, a variety of these objects can be used to keep the crows dispersed, while at the same time providing an attractive visual image (or message) to the public.

For example, a large supermarket or food storage warehouse experiencing crow infestations can string tight lines of fringed Mylar streamers containing small American flags spaced at intervals along the streamers. "Birthday" balloons can also bob in the wind tied to rooftops, lampposts, etc. As these metallic objects flutter and move about in the wind, they help to disperse crows attempting to linger around the storefront or parking lots. Some car dealers have had success in protecting their cars from crow damage using Mylar streamers and various sized banners containing the car dealers’ logos and names. The result is visual advertising and crow control in one clever package.

REPELLENTS AND NETTING. As with other urban pest bird species, crows can be denied access to structural ledges and utility components (rooftop air-conditioning units, etc.) by custom installment of any of the various types of structural repellents and/or bird netting products. Thus, prickly metal and plastic strips, tightly strung wires along ledges, bobbing Daddi-long-leg devices and so forth can protect a specific area from crows and other pest birds. But in most cases, installing these devices solely in an attempt to prevent crows from using the general area is not a cost-effective approach.

HARASSMENT. When crow roosts move into residential or commercial neighborhoods, they can be effectively dispersed by conducting bird harassment programs using several tools and techniques. One popular approach for the past few decades has been the use of bird pyrotechnics. Common pyrotechnics include the use of noise poppers, bird bombs, bangers and various other noise-making devices dispensed into nuisance bird roost areas using hand-held pistols and other devices. Pyrotechnic and other bird dispersal products supplies are readily available to the pest control industry — check with your local pest control supply distributor or visit www.margosupplies.com.

When considering pyrotechnics, local noise ordinances and all safety issues must always be carefully considered.

A valuable on-the-job discussion for conducting effective bird dispersal programs using pyrotechnics and other methods can be obtained on line from the Internet Center for Wildlife Damage (wildlifedamage.unl.edu). At the site, click on "Birds" and you can read or download an entire chapter on how to conduct bird roost dispersal programs for starlings, crows and others.

In the past two years, commercial-level laser guns have become available and have proven effective in dispersing some large crow roosts in urban areas. Compared to pyrotechnics, laser guns offer silence, long range, safety and ease of use. In this time of heightened state of awareness, a silent laser beam at night is an obvious plus as compared to loud gun shots.

These laser guns are essentially heavy-duty laser pointers. Laser beams, when seen by birds on nearby surfaces or when swept through bird roosts frighten the birds and send them flying. (I use an ordinary small laser pointer to scare sparrows and other small birds out of warehouses and stores.)

The lasers can be shined into crow roosts at night and the results are usually immediate. The effectiveness of the laser guns are site-specific (as are all the techniques mentioned previously) and several visits to the site and more than one gun may be required to disperse large, well established roosts.

Laser guns are available from SeaTech Corporation (phone: 888/732-2246, Web site: www.aviandissuader.com) or the company’s distributor, Reed-Joseph Company (Web site: www.reedjoseph.com).

OTHER APPROACHES. Avitrol is registered for crow control and may have some utility under certain circumstances — especially in areas away from the public. However, for crow roosts in urban and suburban areas, the use of this toxicant brings a risk of adverse public relations (due to dead birds). This is likely to be especially true with the recent activities associated with people reporting dead crows, jays and other birds due to the West Nile virus.

Finally, consumers and professionals alike should beware of any ultra-sonic devices claiming to disperse birds, as birds do not hear ultrasonic sounds. In short, the utility of such devices are certainly nothing to crow about (groan).

Author’s note: Thanks to Ms. Judy Loven, Indiana Wildlife Damage Specialist, and to the various pest management professionals providing feedback on their crow management success stories over the years.

Editor’s note: The first part of this column appeared in the October issue of PCT.

The author is president of RMC Pest Management Consulting and can be reached at rcorrigan@pctonline.com.