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.
Tiger Signature
The usual answer where Biscay is involved would be to blame the weather - but in this case, those who understand these things are clear that conditions were good, with only light winds - certainly not enough to blow a healthy bird catastrophically off-course.
The really odd thing is the _sudden_ loss of data. We have seen in the past how a bird that doesn't make it to shore can drift for some time, with the tracker continuing to send data. Nothing like that here.
My geometry isn't good enough to work out if she could have seen the Spanish coast from her last reported location - can anyone else help? Bearing in mind that the reported height isn't necessarily typical.
Rachel R said:My geometry isn't good enough to work out if she could have seen the Spanish coast from her last reported location - can anyone else help? Bearing in mind that the reported height isn't necessarily typical.
I have not worked it out but I am pretty sure she could not see the Spanish coast from her last reported position.
Could she have seen the coast of France? I'm not an osprey. I've been told they have spectacular eyesight. I don't know what that means in human terms. I have been in a plane at various thousand feet (admittedly much higher than she was flying) and been stunned by the view one has of street lamps, ships and the like. If I were tired, I'd certainly make for that area. I still think missing data is the key, one way or the other. Or, Druie's pulling and gnawing of the sat equipment - much like Bynack's of Tore's in 2011(?)
Seasca started her crossing of the Bay of Biscay at 15.15 on 21 August and that is entirely reasonable. So from that point she was committed to flying the Bay of Biscay of which she had no knowledge. for all she knew it could be 1000 miles wide.
We know what she had to do and know that almost every osprey we have ever observed has crossed it without too much difficulty.
Very good points you made deveronside.
I don't believe the Spanish or French coast could be seen from Seasca's last reported position, it would be something like spotting Dover Cliffs from the Tour Eiffel in Paris. Neither I believe she could decide to willingly abort the BoB crossing to land in France if exhausted (and would not shorten the path to an emergency landing, even if she knew about the French Coast).
The loss of data can be simply explained with the Argos satellite not catching the signal at the scheduled transmission time for any reason, this would mean the loss of the entire batch which we now read as "sudden loss of data". But I understand Tiger is suggesting to leave this possibility out of this discussion now, we all will be more than happy if it will turn out that we started a pointless discussion after a false alarm.
The difference I personally see between Blue44 and Seasca is that the latter was last reported in a less hospitable place for a possibly exhausted osprey, with no suitable land for roosting and taking a rest. I saw osprey chicks floating a few seconds with surprising (to me) buoyancy, but they are not puffins and I don't expect they can stay in the water much longer without running into hypothermia issues. And they would be likely unable to rest, they are not designed for living in the water.
We are unlikely to know (under the assumption that data will not be received anymore, nor further analysis of past data will reveal issues with the tracker) what exactly happened and can only reason about probability of events happening. When a transmitter suddenly stops sending data for a bird in its natural standing place and giving no signs of distress before (might be the case for Blue44 and his neighbour BlueYD gone missing this spring) I believe chances that the tracker is to be blamed are higher than when contact is lost with a bird flying over the sea, for reasons explained above. The probability that the tracker fails can be comparable if not the same, but the fact that the bird has less viable options to cope with possible difficulties in one scenario can make a difference in what the most likely cause might be.
I have just prepared a new map from GE.
I am certainly no expert and so far have no experience of birds being lost across the Bay but what I keep pondering is why the data suddenly stopped If Seasca became exhausted, wouldn't the data show her slowing down and losing altitude?
I agree, Patily. And there was no reason for her to be exhausted at that stage - we have seen other birds (Deshar, for example) go far further and longer before succumbing.
I presume that, IF she did become exhausted and slow down, it happened between that last data download and the next that was due. What do you think?
TIGER, as Seasca didn't travel far on the 19th, can we assume that she left LG quite late? I've gone very empty-headed and can't think where to find times.
IMAGICAT
scylla said:TIGER, as Seasca didn't travel far on the 19th, can we assume that she left LG quite late? I've gone very empty-headed and can't think where to find times.
Yes she left Loch Garten at around 1pm on 19 August
But what a journey Seasca has made! As we expected she left the nest site around 13.00 GMT on 19 August and flew S. She was E of Loch Morlich around 13.30 GMT and then flew over the Grampians and crossed into Perth and Kinross at around 14.00 GMT. At around 16.00 GMT she flew over Bannockburn continuing in a southerly direction. At 17.00 GMT she was over New Stevenston, E of Glasgow finally coming to roost at 19.00 GMT in a farming area W of Coalburn in S Lanarkshire. She travelled 190 km on this day – not bad for a bird who had only flown 9 km over about 8 hours a few days before!
From the blog Then there were three