Dead Bird
© Andrew Warner 020211aw2 Dead: One of the sparrows found on Amohau St over the long weekend.

What killed hundreds of dead birds found on a Rotorua central city street? Nobody seems to know.

Rotorua mother Glyssa Bosworth was walking down Amohau St this week when her 1-year-old daughter pointed out a bird on the ground.

Then she saw a few more.

"I could smell something absolutely horrific," Miss Bosworth told The Daily Post.

She turned around and saw "hundreds" of them on the ground around the base of a tall tree in the reserve near the entrance to the Central Mall.

She said she had never seen that many dead birds before.

"There was a humongous pile of them. It was gross."

At first Miss Bosworth thought they were bats, as a few years ago there were reports of bats in some nearby trees. Then she realised they were sparrows.

She thought perhaps bats were killing the birds, or the birds had been poisoned.

Rotorua District Council's regulatory services manager Jim Nicklin said the council was at a loss to explain the dead birds.

The council had reports of the dead birds on Amohau St and believed they had died last Friday.

There were two clean-ups of birds over the long weekend.

"Over Saturday and Sunday a contractor for the council picked up approximately 300 dead sparrows," Mr Nicklin said.

He said on Monday, when Castle Corp staff were doing some mowing on the reserve, they found more dead birds and picked them up.

He said the council did not know why the dead sparrows were there, but he thought it could have been something to do with the stormy weather experienced over that weekend.