'Extra' Peregrine appears at Symonds Yat

14/09/2011 13:55:26 Highly unusual for them to develop at different pace

September 2011: The RSPB have a long standing history of some 25 years pointing out peregrines to the public at the Forestry Commission's Symonds Yat rock and this season has been another huge success - but this year they had one last surprise in store.

FAMILY TIME: A peregrine with her chicks Picture: RSPB

Visitors to the Wye Valley had been enjoying the jaw-dropping spectacle of three peregrine juveniles taking ‘test flights', when a fourth, apparently slightly younger bird soared into the skies. This is highly unusual, and has not been recorded at Symonds Yat before.

'It doesn't make sense'
RSPB People Engagement Officer for Gloucestershire, Matt Brierley was puzzled. ‘Four youngsters for a pair of peregrines in their second breeding season isn't that unusual. They are in good shape and there's plenty of prey to catch. However, peregrine chicks hatch on the same day because incubation starts when all eggs have been laid.

‘So, to have a considerably smaller bird doesn't make that much sense. I associate babies of different sizes with birds such as barn owls. Mum incubates eggs straight after laying so you end up with babies lined up like Russian dolls.'

The nest is out of sight, so Matt doesn't know exactly what happened, he had some possible theories. ‘Food isn't in short supply, but more aggressive chicks may have stolen the lion's share and hampered our fourth youngster's development.

‘More likely, though, is the fourth egg wasn't incubated as well as the others so took a bit longer to hatch. Last year these peregrines stole this territory from older birds, and managed only one youngster. Laying eggs and incubating them well is still clearly a learning curve for them.'