Can aluminum sheeting be used when building a purple martin house at the cottage? Is there anything about aluminum sheeting that would inhibit the birds from using the house?
Aluminum sheeting would not likely stop the martins from nesting in your house. Many commercial purple martin houses are built with aluminum.
But you should be concerned about using the aluminum in cottage country, where a sudden cold snap can happen in late May or early June. Martins start returning as early as late April and may be nesting by mid-May, so their eggs and nestlings, and even the adults, could be fatally chilled by a change in the weather. While wood is a pretty good insulator, metal conducts heat rapidly. An unseasonal heat wave could create an oven-like interior in an aluminum house, which would be equally dangerous to nesting birds.
So if you use aluminum sheeting, insulate the roof of the house with any type of insulating material that birds can’t pick at.