Every time someone calls or emails to schedule an energy audit one of the last things I say to them is, "If you have pet birds, you'll want them to visit the neighbors as the pressure change will bother them."
No one has ever had pet birds, so I've gone on spreading this unneeded advice for years. Well, someone finally had pet birds (complete with a nest and eggs)! The home owner didn't have a place she could take the birds, it was frigid outside and she feared even moving them would also make them quite anxious.
William called his energy audit friends to get more information, but no one had done a blower door test with birds present and no one knew what the actual issue was.
There was one warm day coming up, so we settled on moving the audit to that day. In the interim, William finally tracked down a colleague with the answer. The actual problem is that you can't have your pet birds flying around the house because the blower door fan will suck them in and they will meet their demise.
The home owner was happy to let her birds remain undisturbed on their perch and we used the door farthest from them since even our presence agitated them. Interestingly enough the birds were zebra finches - the very birds I had as a class pet when I taught 4th grade. They are very jittery birds, of which I was happy to be reminded.