. . "It might be 15 minutes well worth preserving you mind.If there is no evidence of birds then rodents will be the most likely culprits and you should place some rodenticide and/or traps in the roof and in bait stations outside.Also consider the possibilities of thermal expansion/contraction, trees brushing the roof in the wind and other animals such as squirrels.I hope that helps.DavidReplyDeleteJoa" . .