More than 120 birds are already in care, and spring and summer are the animal shelter's busy season with up to 400 new birds expected to need nursing in the coming months.

Wildlife supervisor Alanna Kropf blames the breeding season on the high number of injured birds.

Yesterday she visited a peregrine falcon who is sharing an aviary in Calwell with a barn owl.

''More get compromised because they are interacting with us,'' she said.

''In urban areas, where there are lots of stress and there is not that much food around, it's even worse. It can be worse because not only are they worrying about trying to find a mate, they have to find food and a suitable breeding site. We had a magpie come in that had been electrocuted because she had tried to build a nest on a power box.''

Ms Kropf said the peregrine falcon was found trapped in blackberry plants two weeks ago.

''We found she had no fractures or breaks, which is really fortunate because it's her livelihood. She needs to soar they can fly up to 300km per hour.''

RSPCA ACT chief executive Michael Linke said birds accounted for 85 per cent of the wildlife brought to the shelter, with carers nursing a brown goshawk, tawny frogmouth and a few gang-gangs.

He said carers started out nursing birds and as their knowledge increased, they cared for more difficult animals, such as reptiles.

''We are after long-term carers so they can build up their skills,'' he said.

Canberrans who are interested in becoming volunteer wildlife carers will need to attend a training day on September 19.

For more information, call 1300 477 722.

For more on this story, including Mr Linke's comments on the logistics of caring for birds, see the print edition of today's Canberra Times.