There has only been one main discussion point around Loch of the Lowes this week- osprey eggs!
Q: Will the remaining two osprey eggs hatch?
A: Only time will tell! We are still very hopeful but there are three reasons to be only cautiously optimistic: Firstly as we all know, the fertility of this osprey pair has been low the last few years (most likely because of the females age) so we don’t expect a high hatching rate this year. Secondly, both the remaining eggs were jostled and bumped during the crow attack on the nest, and though we haven’t been able to see any damage on either shell, it is possible a tiny crack or hole may have allowed bacteria into the eggs and spoiled chances of a live hatching. Lastly, the eggs have been exposed for more than 40 mins on one occasion during the incubation this year so far, which we can only hope won’t have had any negative affect. Overall I would say we still have a fair chance but we can only wait and see what nature does! We hope we and the birds are lucky and we will be keeping everything crossed!
Q: When will the eggs hatch?
A: The eggs are due to hatch between approx. 20th May and the 29th of May, based on an average incubation of 37-39 days. Slight variation either side of this is also possible.
Q: What will happen if they don’t hatch?
A: Let’s hope this isn’t the case, but in our experience , the female would continue to incubate them until she is absolutely sure there is no chance of hatching- in 2011 this was for 70 days! We would then remove the eggs under license to try and understand why. We would wait for her to give up and loose interest before we interview though, so as not to stress her at all.
Q: Why didn’t the female osprey lay any more eggs when one of hers was stolen by the crow?
A: Ospreys only lay one clutch of eggs per year, unless they loose all their eggs in the first week or so, in which case they may lay another whole clutch. This is because there is limited time in one summer for chicks to mature and if they leave it too late, their offspring won’t be big and strong enough to fly to Africa on their first migration in autumn. If they were to add a late sibling to the mixture in the nest ( by laying a late extra egg to replace a lost one) , the resulting chick would get too bullied by its older siblings.
Speaking of eggs, one of our Great Crested Grebe pairs on the loch is nesting in full view of the hides and they now have at least one egg on their lily pad nest.
Our Blue Tits on live nest box camera in the visitor centre have hatched 7 out of 8 eggs over the last two days- so lots of weird wiggly pink things ( that will grow into beautiful birds) to see live on camera!
And lastly, our local swifts are back- look out for these masters of aerial acrobatics and speed whizzing over the loch!