Thursday, 18 June 2009

Intruder Drama on the Nest

At Osprey nests, it is common in the early days of the season to have intruder Ospreys harass the nest. These are usually young juvenile birds trying to muscle in on the established pairs, who are given short welcome by resident birds. Regular viewers of our main nest here in the Tweed valley will know we certainly had our fair share of these dramas back in April.

It is more unusual however, to have intruders later in the season, so today's events were certainly a surprise! At approximately 11.45 the female started giving alarm calls, and the chicks obediently 'played dead' in the nest. Mum started to mantle ( spreading her wings defensively ) and the shadow of a large bird was seen passing over the nest a few times.

Then dramatically, a strange adult Osprey landed on the nest, clinging to the right hand side for a few seconds before mum flew at it in a rage and chased it off. This intruder bird seemed to fall to the lower branches of the nest tree, stunned, but then took off, and the female gave chase!

She was absent form the nest for at least 10 minutes, which the chicks didn't seem to mind, though we were very relieved when she reappeared to keep them safe. Though another Osprey would not harm the chicks, and opportunist predator may have take the chance to steal a chick, or a heavy shower could have chilled them fatally.

Is this the same intruder female who we saw at the nest in April? We could not seem any coloured leg ring during the brief visit so it is certainly possible- and would account for her boldness. Or could it be another of our youngsters returning to its natal nest? These questions can only be answered if it returns to the nest again- though we hope for our chicks sake , things remain quiet and peaceful.

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