That, in fact, is an indication of something missing in his diet.
Yeah...cat turds. Probably a vitamin deficiency. Eating feces...refection...is a normal activity in some species. Birds can benefit from the nutrients produced by bacterial action in their feces. Just sayin'....
My German Shorthaired Pointer who died at 15 years old lived on Barbacoa Tacos with refried beans.
Once we brought him a Barbacoa taco and it did NOT have beans in it. He refused to eat it.
The next time we went to the restaurant we told the waitress please be sure to put beans on the taco because the last time when she forgot to put beans on the taco, our dog took the taco and threw it up against the wall....HE WAS TICKED!!