On a summer Friday evening in Brownsville’s Joe & Tony Oliveira Park, a pandemonium of squawking parrots is charming enough to cause children playing with tablets to look away from their screens. “Aren’t they awesome?” says parkgoer José Montoya. “I love the noise. . . . If you don’t stop and listen, there’s something wrong with you.”The park is already a hive of activity. Families loudly cheer on a kickball tournament as children playing tag scream after one another and couples cuddle on park benches while blasting pop music from their phones. Once the parrots start arriving, however, all human-generated sounds are drowned out by a cacophony of birdsong. En masse, the parrots sound like the reunion of a large, always-squabbling family whose members, despite their raised voices, ultimately…