Reier and I collected some bits that were just around one of the nest boxes in the city. As the bits were from birds protected by migratory bird laws, we did leave them there once we photographed them.
The first photo is of two skulls - a Blue Jay, and a Northern Flicker. See the difference in the bill shape?
The next couple of photos are of some bits lined up together. In the first picture there are some castings (solid waste that the birds regurgitated), some Blue Jay and pigeon feathers, a radius and ulna (basically the same bones in your forearm), and a combination of feet. There are four different feet here - there is one with a band that is actually from a privately-owned pigeon, one foot with lobed toes that is most likely a Pied-billed Grebe, and two others. I am checking with a couple of experts so I do not mis-identify - check the blog for info! The last photo is a couple of wings - two are from pigeons, and the third is another I am getting confirmation on. Lots of variety for the chicks!