Pettin' in the Park is a 1934Merrie Melodies cartoon directed by Bernard Brown. The song is from Busby Berkeley's Gold Diggers of 1933.
Various bird couples are petting in the park and singing the title song. A policeman is also getting amorous with a nanny, until a penguin pecks at a butterfly on her bottom and she thinks the policeman pinched her. She storms off but quickly hops in another suitor's car. Then the birds all enter the park's diving and swimming contest.
DVD - Gold Diggers of 1933 (unrestored, added as a bonus)