It’s important to periodically (annually is good) check your soffit vent screens around the perimeter of your home to make sure the metal screening is in good condition.  Oftentimes, birds will damage screening, attempting to gain access to the (warm, protected) attic area.  Replacement of damaged screening should be undertaken as soon as practical.  Don’t just cover and block the vents as this can compromise attic ventilation which can lead to mold growth in the attic, a costly problem.  This was discovered at a recent home inspection on Samish Island.