Interesting they mention the Aussie wrens, as I have observed most birds ignore cactus wrens in my corner of the Sonoran Desert. They chatter and alarm constantly. Birds of differing species also pick up when bandits raise false alarms to snatch food from their peers/other species. Fascinating how the differing types comingle and compete. Am glad they're not 10+ feet tall, even the seemingly docile doves can be vicious.