I need some artistic advice

I'm making a glass birdhouse 'Sally Jean' style, for the upcoming Habitat for Humanity auction. I was lucky enough to get an invite to participate in this and I'm really honored. So... I'm making a glass house, but the front will be totally solid (no bird hole), because this will be purely decorative. My problem is the the 'hole'. I want to put something there to represent the whole, but I don't know what. Someone I know is using the standard wood house, and she's dressing up her hole with an vintage optical lens. Super idea, but I don't want to do that same thing as her. What can I use for my 'hole'? I'm using a vintage spoon or fork, bent up for the 'perch'. The style of the house will be a kinda vintage, kinda nature.... so what are your suggestions?????
I'm going to post pictures from start to finish... I think that might be fun.
So then there's the wood house they gave me... I think I will do that more 'whimsical' in style... fun colors, lots of pattern. I'll keep you posted on that too.