Kiwi the parakeet has heard his dude ask Siri things quite a few times -enough that he learned to say it convincingly! So what we see in this video is a bird talking to a machine and the machine talking back. No human necessary.
Note that Kiwi is also imitating that weird human activity of talking to a small device. Who says birds are dumb? Kiwi has also learned to imitate the chime that indicates Siri is activated. I bet he also knows ringtones. -via Viral Viral Videos