Dryer Vent Bird Guard stops birds from nesting in your dryer vent exhaust vent by blocking entry and preserving the looks of your homes exterior. no unsightly cages, no drills, screws or hammers necessary. Bird nests in dryer vents are one of the main causes of home fires due to the restricted air flow from the dryer. Additionally, the birds nest increase drying times for clothes since of the restricted air flow, thus increasing utility bills. Dryer Vent Bird Guard recommends cleaning the vent insert every 6 months to prevent lint buildup, an easy 1 minute job to insure your homes safety..