Tuesday, 31 May 2011

Could this be the end?

Hi All,

As many of you will have seen on our new live web cam our female has not been on the nest incubating her three eggs for the last few days. This comes as a great disappointment to all of us here at the David Marshall Lodge as the eggs were due to start hatching yesterday.

We are still unsure of the reasons why the bird has stopped incubating her eggs, but we are fairly confident that it isn't disturbance as both male and female have been spotted on the nest. Unusually though the female is sitting on the side of the nest and every now and again she will touch one the eggs.

We are trying to say positive but things aren't looking very hopeful, but I will keep you all informed.



  1. There is discussion on the Loch Garten RSPB site that non-hatching osprey eggs this year are more common than usual due to the cold & windy weather during the incubation period. Roy Dennis says there was a similar pattern in 1977 when the weather was similar during May. This does not however explain the pair stopping incubation - none of the Loch of the Lowes eggs have hatched but they are still being incubated 42-48 days after hatching.

  2. I am not sure that the cold and the wind is the only problem for these failures.
    I believe another problem may be due to the excessive wet weather, neither the birds or the eggs can deal with that, not only surface contact with water but with excess moisture entering the egg, carried in the air.
    High moisture or humidity levels cause serious problems for a growing embryo within an egg, certainly within an incubator.
    As an egg ages because the shell is porous, it takes in air and an air sack within the egg increases in volume. one way of telling if an egg is fresh is to put it into water and if it sinks its fresh.if it floats the egg is not fresh ,because the moisture is slowly draning from it.
    This moisture content is essential for embryo growth. During incubation fresh air and moisture in the air goes in and poisons such as Co2 goes out.
    Usually because our latitude and martitime climate has a reasonable balance, moisture not usually a problem.
    However, with the weather situation within the last two weeks there has been a serious increase in dampness and then some sun heating it up, It is possible all this has got into the incubating eggs, (not only in Aberfoyle ).
    A number of things happen because more is going in than comming out, the chick gets big and trapped in a growing level of water ,it can`t move easily ,can`t get into position to break into the air sack which will likely be waterlogged. also the inner membrane is elastic and the chick cant peirce it and becomes eggbound. also the muck surrounding the chick can dry out and it cant work its beak.
    Whatever happened it was major simultanious catastrophe her behavoiour showed this, after proloned devoted parenting by both birds she was on and of the eggs all weekend , for a short time this might be normal as, if the chick is working it doesnt need heat or overheat but prolonged absence and a quick exit,might mean she knew exactly what was happening.(O.M.H.O.)

    David Erskine RSPB Volunteer Aberfoyle.

    On a brighter note only 10 months till March

  3. I will try again and maybe sucessful this time.
    Ospreyfreak thank you for your views on the very sad news at Aberfoyle.
    I have e-mailed Lowes and only an idea, maybe silly. When Lady and Laird go, I hope they look at the eggs to see if there had been any activity in the eggs. Maybe this will tell whether it was due to the eggs being infertile and if not the terrible weather in May. I am not an expert so maybe silly. I do think it is worth looking however too many questions was the lack of incubating at the start may been a factor. Maybe we will never know?
    Very strange behaviour by the female here and just does not make sense and has you have said, maybe the female knew.
    I was so looking forward to a hatching visiting on Monday and it would of been my first visit.
    Here's hoping metal ring and his girl come back next year, somehow I do not think he will give up this nest.

  4. There is nothing wrong at all with the female on the Dunkeld nest.
    The bird is in lay, laying a full clutch.
    She is regular and on time, therefore she is fertile.
    Any fertility issues should be directed to the male bird. Otherwise, the Hatchability of the eggs should be considered, an entirely different matter altogether.

  5. Ospreyfreak thank you for your comments and it so very much appreciated.
    It has not been a good season for so many nests and it makes us amateurs, not believe everything that is said and make 2 + 2 = 5. I am so interested in Ospreys and learning all the time.
    Nature is nature and the weather is so unpredictable, very sad and Robert thank you for letting us know the situation.
    So sorry and feel for the team, the dedication you put into these wonderful birds however being positive as you say Ospreyfreak, not quite 10months now to until March.
    I will visit during the week and look forward very much to it. I love Aberfoyle and have stayed so many times at Cobeland.

  6. This is a fascinating discussion, I am the Wildlife and Community Officer for the RSPB at Wigtown, Dumfries and Galloway.

    I have to confess that I hadn't been following the Aberfoyle Osprey story this year until now, as I have been so busy with setting up the Wigtown Bay Osprey Project with the RSPB as lead partner.

    I used to work at the RSPB Glaslyn Project in 2005, and still have strong links with both the Glaslyn, and Dyfi Welsh sites, and the NTS Threave and WWT Caerlaverock, Dumfries and Galloway sites, so just haven't had the time to follow all other osprey projects.

    The reason for my specific interest in this discussion is that we lost our youngest chick this year a few days after hatching, again due to bad weather and lack of fish brought in as a result.

    However, although I was not in post at the time as I had a broken ankle, I have been told that our youngest chick struggled to fight free from it's egg membrane for most of its first day and was thought to have exhausted itself in trying to break free before then spending the next two to three days not being fed due to the weather.

    Perhaps Ospreyfreak's hypothesis about water logging strengthening the egg membrane was a major contributing factor to the cause of death.

    Despite this, our other two chicks JD and JC have fledged in the past couple of days, and are both doing really well, as is H/D our resident female who I'm told hatched in 1998 from an Aberfoyle nest. Another good link between our projects.

    For more information about the Wigtown Bay Project please see our Blog hosted by the nearby Crook of Baldoon RSPB Reserve.


    I will publicise your link on our Blog.


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