The resident said there had been people over for drinks but "nothing major, not full-on drinks" and they did not know why Mr Birch was attacked.
"That's the weird thing about it, he must have been hiding in the bush for a while."
He said the man "took off" after the attack.
Mr Birch was placed in an induced coma and transported by Life Flight's air ambulance from Hood Aerodrome to Wellington in a critical condition.
His attacker, believed to be from Wellington, had not been found yesterday afternoon.
Detective Senior Sergeant Scott Miller told the Times-Age the attack happened after an "altercation" and said the suspect was known to police.
Crime scene examiners, at the property for much of Wednesday, recovered a number of items that could have been the attacker's weapon, said Mr Miller.
Mr Birch's younger brother, Dylan, at his bedside with family at Wellington Regional Hospital's Intensive Care Unit, says his brother is now conscious and recognises family members, but is on strong medication.
His brother "looks a mess", but is doing well.
"I walked in and he recognised me straightaway. He's been whacked four times, but he only remembers the first hit.
"There's one major one on the hairline."
He said his brother's first question was where his pitbull dog, Boika, was.
He said the dog had cowered in the bushes right beside where his brother was attacked, and had remained hidden there until family found him.
"He didn't move from that spot."
He said Mr Birch would talk to police "as soon as he can speak a whole full sentence" and expected him to be moved to a general ward today or tomorrow.