Osprey Diary Wed 3rd July

Our ospreys have had another calm day in the mild weather today, with the sunny spells a welcome relief after yesterday’s downpours. There have been two fish deliveries so far today, with a large pike this afternoon just before 5pm. Interestingly the chick showed some interest in trying to feed itself today, when the female was briefly off the nest and the remains of the morning’s fish were still nearby. It won’t be able to feed itself properly though until it is able to grasp fully with its talons. The chick is also noticeably standing ‘flatfooted’ and is not so wobbly on its legs – another good sign of its strong development.

 Q: When will the chick reach full size and fly for the first time (fledge) ?

A: Ospreys generally take 6-7 weeks before they reach full adult size. By about seven weeks of age, osprey chicks are ready to test their wings for the first time. They often exercise on the edge of the nest and lift off in short hops before taking off properly for the first time around 8 weeks of age.

Q; Why is the female osprey still staying on the nest most of the time? Why is she now leaving the chicks for short periods?

A: The chick is still vulnerable and she is ensuring she is always on hand to protect it if an opportunistic predator should pass by (such as a heron or buzzard) or a heavy rain shower should threaten to soak the chick. When the female wants to stretch, wash or simply have a break, she now can as long as she is still nearby in case of emergencies- when she is off camera, she is often on a very nearby tree.

 Q: Isn’t the chick too big to fit under mum? Why is she still sitting on it?

A: Our single chick is getting so big it hardly fits under his mother- though the female will continue to use her body to shield it from the weather and keep it warm until it is fully feathered and more waterproof- otherwise it could still die of exposure, as its down covering isn’t sufficient protection yet.

Q: How do the birds cope with all the rain?

A: Our ospreys are remarkably resilient, and can cope with all weathers, from rain, snow to extreme heat. Our female will adjust her posture to best cover the chick, as she did yesterday in the heavy rain, and she will occasionally stand up and shake to prevent getting  waterlogged herself.

 Q: What Gender is the chick and does the darker breast on it mean it’s female?

A: The short answer is that we don’t know yet if it is male or female. There is no ‘external plumbing’ in birds, and in Ospreys no clear difference in plumage (unlike say in ducks) so clues are very small. Generally female Ospreys will end up 30% larger than the males but in chicks with different ages and feeding, this can be misleading as an older well fed male may be larger than a poorly nourished or younger female. Experts can usually tell at ringing if the chick has thicker legs that it is a female- but the only way to be 100% sure is a DNA test, or waiting for 3 years to see its behaviour at mating!  Whilst in adults, the females generally have darker breasts than males, this is not always reliable. In chicks, plumage can change a huge amount in the first two years so it is not a reliable indicator of gender.

 Q: Will we be naming the chick?

A: We don’t generally have a policy of naming our wild Ospreys but usually, when chicks are ringed, they are given the name suggested by their Darvic ring’s (coloured leg band) unique combination of letters and numbers.

Preface

Our ospreys have had another calm day in the mild weather today, with the sunny spells a welcome relief after yesterday’s downpours. There have been two fish deliveries so far …

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