Osprey Dairy Tuesday 28th May

The wait for hatching goes on……. Yes we are all biting our nails here too. Yes we are concerned the eggs may have failed after they were left exposed during incubation for more than an hour. No we haven’t given up hope , or anywhere near it yet- there is still plenty of time yet as eggs 2-4 are not even ‘due’ yet.

Meanwhile , here’s more great Osprey questions from our readers and visitors:

Q: Could the eggs have gotten too cold when the male left them unattended a couple of weeks ago?

A: Yes this is possible, and this would cause the embryos inside to die as they need a very steady temperature to incubate successfully. This is a real concern but are hopeful that as it was a warm day, the harm may have been minimal.

Q: Could the eggs have overheated last weekend? Could the egg shells have become too hard for the chicks to be able to hatch?

A: It is unlikely the eggs got too hot (incubation temperature is usually over 30 degrees C, but humidity is also important, and sometimes hot dry weather can make the shells a little tougher than normal.

Q: Can the birds tell if the chicks are alive inside the eggs? How long will they keep incubating?

A: This is difficult to tell- we know the birds can hear chicks making small sounds in the eggs and that they respond to these. However, this female and her mate continued to incubate eggs in 2011 where the chicks had died inside, for an incredible 70days, so they must have instinctively thought there was some hope of them hatching. They only gave up incubating long after any chance of hatching had past- almost double the usual incubation time.

Q: Could the ospreys lay another clutch of eggs this year?

A: No, ospreys never ‘double clutch’ (lay two lots of eggs and raise two broods in one year) unlike many smaller birds. This is because they know that a late laid brood will not have enough time to mature sufficiently to make an autumn migration safely, and these chicks would be highly unlikely to survive. Long lived birds like ospreys will simply wait till next year to try again. This is why nest disturbance by humans of ospreys is such a problem- it wipes out their whole breeding year.

 Occasionally if Ospreys loose eggs in the first week or so, they may lay more (such as EJ at Loch Garten this year who laid egg 3 and 4 after her mate destroyed 1 and 2) but not after a whole incubation has been unsuccessful.

Q: If these eggs don’t hatch how will we know why?

A: If these eggs don’t hatch, we will wait until the birds naturally give up incubating them, so as not to stress them. We will then apply for a license to remove eggs from the nest for analysis, which should tell us if they were ever fertile, and if so at what stage embryos died, if this is the case.

Q: I’d like to know something about the scratching noise audible on the video stream. It seems to be often accompanied by blue tit calls – could they be stealing stuff from around the microphone for their nests, as they did in a previous year?

A: You are absolutely right- wee birds often steal the microphones fluffy covering for their own nest lining and the Blue tit has been seen on the nest camera frequently, so we suspect this is the culprit. We have had numerous small birds on the nest over the years- these wee birds have nothing to fear from a fish hunting specialist like ospreys, who seem to tolerate them well.

Lastly someone got in touch to ask what “ Drookit” meant in Lindseys Blog post yesterday- it’s a Scottish word well explained in this picture of a Red Squirrel:

Drookit Red Squirrel at Balgavies - 8.5.13 - copyright Alex Shepherd
Drookit Squirrel by Alex Shepherd

Ranger Emma

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The wait for hatching goes on……. Yes we are all biting our nails here too. Yes we are concerned the eggs may have failed after they were left exposed during …

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