Date of this Version
One technique for repelling or excluding birds is to stretch wires, monofilament lines, or nylon strings across sites needing protection. Wires or lines spaced at various intervals and in various configurations have successfully repelled birds such as ring-billed (Larus delawarensis) and/or herring (L. argentatus) gulls, and brant (Branta bernicla bernicla) from reservoirs, sanitary landfills, fish hatcheries, nesting areas, public places, or farm fields. Black thread has been suggested for repelling small birds such as sparrows (unspecified) from garden seedlings and bullfinches (unspecified) from fruit trees. Recent observations in New Mexico indicated that monofilament lines spaced at 30-cm (1-ft) intervals repelled house sparrows (Passer domesticus) and other birds from various feeding sites and barn swallows (Hirundo rustica) from nesting sites. Experiments in Nebraska have tested size (1.8-, 5.4-, and 9-kg test), color (clear and fluorescent golden), orientation (north-south, east-west, horizontal, vertical) and/or spacing (30 and 60 cm) of monofilament lines in a grape vineyard and at feeding stations. Results of food consumption and bird count data indicate that all treatments repelled house sparrows. Although the reasons lines repel certain birds is not fully understood, it appears that they have probable applications for excluding or repelling certain terrestrial as well as aquatic species.