Mr Patel, 21, a student living in Mt Roskill, said the two men had a bag of eggs with them which he believed were also collected from the park.
"They were really rough with the animals and didn't care if they lived or died when they were shoved into the bag, which made me think that these people wanted them for food and not pets."
Warwick Palmer, who wrote to the Herald, said he had a friend who saw another man at Cornwall Park who "caught a pheasant, wrung its neck in front of passersby and then took off with it in his car".
The Auckland Waikato Fish and Game Council says the number of wild ducks and geese from parks being caught and killed is on the rise, and he wants the Auckland Council to put up signs to deter poaching.
"We don't have numbers, but it seems to be on the rise," said Fish and Game northern wildlife manager John Dyer.
Unauthorised removal of birds from parks was an offence under the Wildlife Act, and offenders could be fined up to $5000.
He said birds being poached were primarily ducks and geese, but "anything else not tied down or fenced off, such as pukeko, quail and swans", was also being stolen.
And he warned it could spell the end for the Cornwall Park pheasants.
"Pheasants have probably been there since the 1860s; now the area is built over if these last pheasants are killed, that's it," said Mr Dyer. "They'll never be seen there again as pheasants don't fly that far."
Cornwall Park director Michael Ayrton said he was unaware of the park having lost livestock through theft and was shocked to learn about the pheasant incident.
Council spokeswoman Lydia Blatch said anyone seeing people taking wildlife in council parks should call the police or the council on (09) 301-0101.