That is an unbroken neckring. This is copied from this website.

http://www.enaturalist.org/faq/11

"The Northern Ringneck (D. p. edwardsii) typically has an unbroken neck ring and a solid yellow or orange-yellow belly and no or few spots on the belly.

The Prairie Ringneck (D. p. arnyi) typically has an unbroken neck ring, a yellow or orange-yellow belly becoming reddish toward the tail tip and lots of irregular spots on the belly.

The Southern Ringneck (D. p. punctatus) typically has a broken neck ring..."

I have 2 Southern Ringnecks. Big Eaters once they settle in. Look at my pics.