Officer Delinko is a hard-working and dedicated police officer. The problem is that he doesn't have much to do as a member of the Coconut Grove police force. That's why he leaps at the chance to play detective when he discovers what's been going on at the building site.
At first, he doesn't quite know what this could all mean, but he's sure he's on to something. The more he plays Sherlock Holmes and the deeper he digs, the more intriguing he finds the situation with the owls. Delinko's also quite an ambitious man. He wants to solve a serious crime in order to gain respect and admiration. This would make him a hero and perhaps convince his superiors that he's worthy of promotion.
That being said, Delinko is not prepared to compromise his morality in order to get promoted; he does have principles. Initially, he's incredibly hostile towards Mullet Fingers, whom he sees as nothing more than a trouble-maker and vandal. But once he discovers why Mullet Fingers has been messing around with the construction site, he changes his mind and realizes that this strange kid is actually one of the good guys. This shows us that Delinko has a conscience and has a great deal of empathy.