The birds see the reflection of trees in windows and fly into them.

Ruru are adorably cute and their nocturnal call is distinctive, but it seems at times their natural GPS could do with an adjustment.

Two of the birds, also known as morepork, have been brought to the New Plymouth Vet Group by members of the public this month - one of the birds was found dazed on the road, presumably after being hit by a car, and one had a broken shoulder after flying into a window.

"They see the reflection of the trees in the windows and they just fly in," said vet Anne Terrill, whose practice has dealt with five ruru this year.

ANDY JACKSON/STUFF The birds will stay until they can eat by themselves and fly, before continuing their rehabilitation, probably at Brooklands Zoo.

Some have been brought in after windy periods, she said.

READ MORE:

* Concussed morepork makes full recovery at Brooklands Zoo

* Guess hoot: Morepork visitor surprises resident

* Cat owner saves fantail from jaws of pet, takes it to the vet

* Porky the morepork put down after broken wing failed to heal

"Some of them are fledglings, so they might not have the coordination or the strength to deal with the wind."

ANDY JACKSON/STUFF The New Plymouth Veterinary Group have looked after five ruru, or morepork, as well as other wild birds this year.

And ruru are not the only birds to have been seeking assistance.

Other patients have included kererū, pūkeko, kingfisher and even blue penguins.

As cute and fluffy as the ruru look, staff always wear heavy gloves to handle them, said reception lead Clare Richardson.

ANDY JACKSON/STUFF Vet Anne Terrill from New Plymouth Veterinary Group with one of the recovering ruru.

"They have got really really sharp claws and beaks.

"These animals are wild so they go into survival mode.

"They cling on and they just want to hold on to something," Terrill said. "If you're aren't quick enough to put a pen or a piece of wood there, it's your finger.

"When they get a little bit upset with you, they click their beaks."

Staff have had to weigh down the lids of the birds' containers after arriving in the morning to find the feathered guests on the loose.

They will stay at the vet clinic until they are able to eat by themselves and fly again - often it is a matter of waiting for feathers to grow back - and then they will be sent on for rehabilitation, often to Brooklands Zoo or a farm in Turakina.

The rarer birds, such as penguins and kiwi, are usually sent down to Massey University straight after triage.

Once they are ready to return to the wild, they are usually released in the same place they were found.

"We don't win with a lot of birds; often by the time we see them they're quite sick," Terrill said.

"When we actually get a chance to release them it's kind of cool."