Does anyone know the type of squash that is used in making the birdhouses....?

a friend gave me a birdhouse made from a squash shell, I wanted to try it myself, the friend said that as far as they know, the name of the squash if actually called the "birdhouse" squash, but added that he also heard the squash by another name and I could have swore he said "ernut" squash, so I was at the grocery store the other day and saw "ernut" squashes there, so I picked one up and showed it to him and he said, I'm not sure if that's the kind used, but said, it looks like it though, don't it, same shape and all, I started to cut the hole in the side and found that the inside is pretty thick, so naturally uming it has to be cored out to let it dry out, but I think if I worked too hard at it to core it out it would eventually crack or give on the sides, so I just cored out a thin/medium layer and now have it drying. According to my friend the kind of squash used for the bird houses, dries well and doesn't wilt or mold easily when drying, so I can only see what happens with this one, but thought if anyone knows about this particular subject, they could help me out with how to do it and exactly which type squash to get, I've never seen a squash called "birdhouse" squash, but it's shaped exactly like the ernut ones are, any help would be much appreciated. Thanks In Advance!