A couple of weeks ago, I heard some chirping from my front door. I investigated it, and found that there is a hole in the soffet of the porch roof. I know how to fix the issue. I know that due to the construction of the roof, the birds are not in my house, just the porch roof. I do not want to kill the birds, just prevent them from nesting there in the future. How long after not hearing chirping can I go up and block the hole off?