A roof dryer vent can be difficult to maintain because animals love to make their home on or around the dryer vent. The reason is simple; the dryer vent is warm. One of the main offenders in the roof dryer vent animal problem is birds. When a bird makes a nest in a roof dryer vent, it creates a dangerous situation for a couple of reasons. Lint can build up faster when the roof vent is blocked, and this creates a fire hazard. When the vent is blocked, the dryer has to work harder to generate warm air and this can cause damage to your dryer.