“It’s been a difficult year, but it’s still been a successful year,” Miller said. On average and as a rule rule-of-thumb, Miller said they try to successfully fledge one chick per two nesting pairs, a productivity rate of 0.5 or higher. This season’s 140 chicks, bred between late August and mid-March, saw a productivity rate of about 0.7. Ken Atkinson/Supplied Fledglings can’t fly for at least six weeks, and they need to forage for food themselves from day one. “Around 140 is a good result, if it dropped a bit below that we would still have been happy, but last year we did have over 200 successful fledglings.”