We have 7 vents in our house walls. - 2 upstairs bathroom vents - 1 main floor bathroom vent, 1 kitchen vent - 2 vents (one "in", one "out) for HRV/Air Exchange in basement - dryer vent (in basement). They are the basic, cheap louvered style (plastic slats). Sometimes the wind blows them up, and they stay up - rain gets in. I intended to replace them all at some point - with something shielded, heavy flap, etc. Now I am hearing bird noises from the kitchen vent - seems like there might be an occupant - possibly a nest. So vent inspection/cleaning/replacement, has gone from the lower part of the list to higher priority. Any advice ?