Not that mere scientific evidence will change the minds of hardcore creationists, but I personally think
this is pretty compelling:
"The vessels and contents are similar in all respects to blood vessels recovered from ... ostrich bone," they reported in a paper bring published Friday in the journal Science.
Birdies evolved from dinosaurs. Will the creationists try to rationalize that God was recycling materials, and just happened to use the same base in avians as He did in saurians? I wonder.