Seasca.....What Do You Really Think?

Yesterday we got the amazing news that Seasca was missing in action presumed dead. Now she may well be but I find myself really very puzzled by it all as the more I think about it the less convinced I am that the evidence shows this.

At the second last update I had no worries whatsoever. A well fed juvenile osprey on her first migration what could go wrong. Well unfortunately lots can often go wrong but there are usually clues as to the reason.

If I had one concern it was that she was losing out in the fish war on the nest. However Mallachie in 2009 was losing out in the fish war and she got to Africa no trouble.

In times like this people are usually only too willing to blame the tracker. I am very reluctant to blame the tracker but in this case it may well be the only explanation.

Firstly it may be delayed data. We know that can and does happen. So on Thursday the missing data may turn up. Not as unlikely as you might think.

So if no data does turn up then it is time to look to other reasons.

In November 2012 Blue 44 was an incredibly well fed bird heading toward Africa when he simply disappeared without trace. Now that seems the closest parallel with the present case. Again not a hint of an explanation why. Was it a tracker problem or did Blue 44 come to catastrophic harm?

 Well that has got this started and see what parallels we can come up with. 

  • Hazel b said:

    I always point out that Breagha coming from a fourth egg would normally have almost zero chance yet here is is poised to be the first Loch Garten bird to carry a functioning tracker to Africa and back.

    This gives hope for Druie, which seemed to be the weakest chick at the beginning of the season, being the third sibling. Unfortunately, she is not tracked.

  • Breagh might have been from the fourth egg but as he was the second chick I suspect that is what really counts.  Has any research found that the eggs of a first clutch grow progressively weaker as each one appears?  Druie was quite a strong character and from what I've heard about Garten and Bynack so were they.

    Our herring gulls are red listed birds.  Think about that the next time you hear some flaming idiot calling for a cull of them.

  • Clare Bailey said:

    Breagh might have been from the fourth egg but as he was the second chick I suspect that is what really counts.  Has any research found that the eggs of a first clutch grow progressively weaker as each one appears?  Druie was quite a strong character and from what I've heard about Garten and Bynack so were they.

    I am pretty certain that the eggs are mostly the same but Breagha benefited greatly from not having two large siblings to bash him about. 

  • Good morning all. I've been thinking about Alba's and Seasca's similar migration tracks and have had a look at GE again. I notice that Alba left on 19 August and wasn't in the Bay of Biscay until the 26th. That's fairly leisurely, really. She speeded up after that. Seasca also left on the 19th but was in the Bay on the 21st.  

  • Hazel b said:
    I am pretty certain that the eggs are mostly the same but Breagha benefited greatly from not having two large siblings to bash him about. 

    Definitely!  I can appreciate why EJ doesn't try to raise more than three young.

    Our herring gulls are red listed birds.  Think about that the next time you hear some flaming idiot calling for a cull of them.

  • deveronside said:

    Good morning all. I've been thinking about Alba's and Seasca's similar migration tracks and have had a look at GE again. I notice that Alba left on 19 August and wasn't in the Bay of Biscay until the 26th. That's fairly leisurely, really. She speeded up after that. Seasca also left on the 19th but was in the Bay on the 21st.  

    Yes I think that Seasca had a superfast transit of Britain. Not sure how fast she was compared to Blue YD. 

  • Yes, Tiger, I suspect that other young ospreys may have gone as fast but it looks as though that's quite unusual for the LG young - even the fast migrators.

  • Have been catching up on this fascinating thread - thank you all for your insights.

    It seems to me that in Seasca's 'superfast transit of Britain' (cf Tiger!) she didn't really have much time to attempt to fish for herself in the couple of days before she started across the Bay. We know juveniles are likely to need more fishing attempts to be successful, therefore would be likely to loiter long enough for it to show up on the data, as it is doing for Millie near the river Derwent for example. So it is very likely she embarked on the BoB crossing rather hungrier and less hydrated than other birds doing the same.

    The other thing we just don't know is what else might have been in the Bay of Biscay at the time. Is it possible, for example that she could have flown into some kind of obstacle (a large buoy or even a ship, although they tend to be well lit at night I think) by accident during the night? It's unlikely I guess, but the suddenness of data loss is odd if it was just gradual exhaustion, as others have observed.

    Fingers crossed for Millie. She seems to be taking a steadier approach to her migration. I remember how Breagha took his time last year and look how well he is still doing. And for Druie, wherever she is now.

    Chocoholix shiny new 2018 Interactive Osprey & Chick Chart! (with clickable links!)

  • chocoholix said:
    We know juveniles are likely to need more fishing attempts to be successful, therefore would be likely to loiter long enough for it to show up on the data, as it is doing for Millie near the river Derwent for example.

    In my view most  juveniles do not try to fish until their first stopover. We have seen this again and again in previously tracked birds.

    That is also the view of Roy Dennis expressed in his book "Life of Ospreys". 

  • Hazel b said:
    In my view most  juveniles do not try to fish until their first stopover. We have seen this again and again in previously tracked birds.

    Thanks Tiger - so that plus the actual tracking data do suggest that Seasca had almost certainly not eaten (and therefore taken on any liquid) before heading out over the Bay of Biscay, and she would have burned up a lot of calories zipping through the UK and past the tip of Franc in the previous two days...

    Chocoholix shiny new 2018 Interactive Osprey & Chick Chart! (with clickable links!)