where to get bird skulls?

I do them all the time, beetles is the way to do them

 

Bugs. Keep an eye on the sclerotic rings while the bugs clean it and you will be able to save those as well.

 

I never save the sclerotic rings. Personally I dont think theyre worth the effort and I actually like the look of the skull without them. Bird skulls are easy to do though as long as you have beetles.
Degrease in room temp ammonia probably half and half with water because if you use the normal 125 degree temps with dawn like other skulls they will fall apart and are a pain to put back together.

 

I agree with Weasel about the scelerotic rings. I never put them in even if I manage to preserve them. I'm used to seeing the skulls without the rings, and I always think they look a bit odd with them in place.
I macerate all my stuff, as beetles are hard to come by here, but I find that the results depend on the type and age of the bird. Some come out almost whole, with a few bones separated, but occasionally the thing comes right apart, and can be a pain to reconstruct.
I use acetone for degreasing, and find that works really well. Something as small as your average bird skull can be done in a small jam jar, so doesn't take a great deal of acetone.

 

we have some pheasant skulls .50 w/feathers .75without 20headmin plus shipping thanks Dano

 

if you have a large radio tower near you and have access to the property around it you should have an unlimited supply of all kinds of birds. The tower in my home town is almost 3000 ft tall and there are multiple levels of guide wires. the ground is littered with bird carcasses from them hitting the wires. I used a bird carcass for a science fair project back in highschool. just looked around til I found one completely flesh free and assembled it.