"He was maniac, completely maniac. I was screaming at him and he had no response," the woman told the Herald.
She believes the man separated the pukeko chick from its mum and chased it with the intent to kill.
The woman says a man fitting the same description did the same thing in front of her friend, who also lives on the same street, just last week.
"These are not isolated cases," the woman says.
"He is deranged, dangerous and he will do it again," she added. "It could be cats, it could be dogs ... it could be kids."
On both occasions, the man, who the witness believes to be a local from Mt Albert, rode off on his bike with the dead bird.
The woman says the incident has been reported to police and the SPCA.
Police have confirmed they received a report around 11am "of someone allegedly mistreating an animal".
The SPCA has been contacted for comment.