This is a double shell, solar-vented cool birdhouse for the Birdhouse Challenge, printable in one piece. Your chicks will thank you!

There is a drain at the bottom and a ring of ventilation holes at the bottom and top of the inner shell, and another ring of slots and holes at the bottom and top of the outer shell. Any sunlight on the outer shell sets up a convection cycle with cooler air being drawn in through the lower ring of slots and rising to exit the large holes, so the inner shell and nest remain cooler. A post and ring joins the two shells at the top for a sturdy hanger. The roof, lack of a perch, and gap between shells makes it difficult for a predator to reach the eggs or chicks. There's no bird bath because chicks won't appreciate the resulting disturbance or encouragement of predators, and the opening is high enough that the chicks won't fall out before they are ready.

Please let me know how you do!

I used drsfostersmith.com/pic/article.cfm?aid=2194 as a guide to design. Sizing - check. Heating and cooling - check, but there's no insulation for winter except to cover exterior holes to trap dead air. Proper drainage - check. Safety - check, while there's no metal plate, there are two openings that would have to be enlarged, and a squirrel would have trouble hanging on anyway. Mounting and access - check/fail. There is no cleanout plug - you'll have to use a hooked wire and fish out all the nesting materials to clean it out.