Bang on it with a solid object and the noise will make.
Birds in exhaust vent.
Hook up a leaf blower.
This can become a health issue.
Go to your attic or the roof if you don t have an attic and find the vent.
Birds in vents is a very common problem that is found in most cities and towns on the eastern seaboard birds will start attempting to get into vents usually in the later part of march they will attempt to get into any vent in the home some of the more common vents that you will find birds in are kitchen vents and higher up bathroom vents.
Bird nests in your bathroom vent can also mean that the dust debris and droppings are disturbed and blown into your bathroom every time the fan is turned on.
Signs of a bird stuck in a vent scratching sounds as the bird attempts to escape chirping if the bird is young.
Disconnect the beginning or interior end of the vent from the fan.
How to remove birds from an exhaust vent.