An estimated 2,900 dryer fires are reported each year, according to the US Fire Administration's National Fire Incident Reporting System. Many of these are caused by a clogged dryer vent.
The vent running from your dryer carries hot air and lint from your dryer and blows it outside. During the spring, birds like to use dryer vents as a cozy place to build a nest. When the vent is blocked with a nest -- or anything else -- hot air builds up and can catch deposits of lint in the vent or dryer on fire.
Finding and removing a nest
Go outside and look for a hole in the side of your house, near the ground. The hole may have a metal or plastic hood over it. This is your dryer's exit vent.
While your dryer is running, stick your hand over the exit vent. You should feel warm, moist air coming from the it. If you feel little to nothing, there's probably a clog somewhere.
If it's a nest, your first clue will be bird droppings around the vent. Another clue may be bits of straw, grass and other debris by the hole. Grab a flashlight and shine it into the hole. See a nest?
The easiest way to remove a nest is by sticking a pair of long barbecue tongs into the hole and grabbing the nest. If you're gentle, you may be able to pull the nest out, intact, and place it somewhere else. Be sure to wear gloves and a mask while removing to nest to prevent contamination from any bacteria that may be in the nest.
When you're done, spray the vent with disinfectant and let it dry completely before starting a load.
If you don't see a nest, but still think your vent may be clogged, call a professional vent cleaning service. You may have a clog farther inside the vent that you can't see.
Preventing a nest
To prevent birds from making your dryer vent a home, purchase a louvered vent cap like this Whirlpool version or this version by Deflecto. These caps have flaps that open when the dryer is in use and close when it isn't, keeping out any feathered friends.
While you're at it, here's some more ways to prevent fires and dry more efficiently by deep-cleaning your dryer.