Art Glass Bird

Another find yesterday. I went out hoping to find a piece of art glass and just when I thought that nothing would be found, this caught my eye. I not had any time to thoroughly investigate it, so if anyone out there can help, let me know. Should there be something in the area that looks like it should hold an egg, maybe or is it simply a place for hard candy? I have a couple items that I am considering putting in the spot that might work, I will try them out later. Hoping to find a nice small art sphere to put in it permanently.