Leri's Dilemma
It is now almost four weeks since Leri's transmitter sent its last signal. Despite spending much of this time trying to figure out exactly what has happened to her, we cannot come up with a definitive conclusion.
These are the last data points we have for Leri from October 24th to 29th.
Each satellite transmitter sends out an activity reading every time the transmitter moves. This is a randomly generated number that changes for every new position, the problem is, from October 24th onwards this number stayed exactly the same, never changing, indicating that the transmitter was not moving. (See previous Leri diary for more information on this). Worryingly, no GPS points came in at all for October 25th and 26th. For the next three days however, October 27th, 28th and 29th, we received a full set of data.
This is the big dilemma: Despite this activity reading not changing, and notwithstanding the fact that many of these GPS readings were coming from one central location, we have several other readings that showed the tracker in other positions - see the map above. These other positions are several hundreds of metres apart form each other but Leri/the tracker, kept coming back to the same central position, time after time. The data is conflicting and confusing. If the activity reading was indicating no movement, why all these other GPS points? It's a bit like stopping your car at a red light and then looking at the speedometer showing your doing 60mph - something isn't right.
What are the options? Initially we thought Leri had been predated and was being dragged around which would explain the other GPS points; but which animal would keep taking its prey back to the same position every few hours? Maybe she was floating on the water, but surely she wouldn't find herself coming back to the same position repeatedly?. Maybe the GPS positions outside this central location were slightly inaccurate and that she wasn't infact moving at all? Well, many of these other locations were of 'Class 3' quality - the most accurate you can get. These should be more or less spot on. As a test we looked back at Leri's positions for those weeks before she started her migration where we knew where she was in the Dyfi - on the nest, a feeding tree, the camera tree and so on.. her tracker was incredibly accurate, down to just a metre or two. Several satellites pass over the tracker to send these Class 3 readings, up to six or seven sometimes, these GPS positions should be spot on.
The only logical explanation we can come up with is that Leri had found a favourite perching tree (i.e. at this central GPS location on the map) and was periodically flying off to nearby areas to fish, preen, perch etc, and then coming back to her central perch.
Finally we have the research sent in to us from Frederic. He found a dead acacia tree at this central spot, ideal for an osprey to perch on. He also found white droppings nearby (osprey droppings are white). He found many catfish in shallow water - very easy for an osprey to catch which would negate any need to fly far and wide in search of food. But most importantly perhaps, he did not find Leri's body nor her tracker.
Frederic with Cheikh Aïdara looking for Leri in Senegal - image Rozenn Le Roux
So we have a situation where we simply don't know what has happened to Leri. If suddenly we get another signal from her transmitter, we will of course let you know but after four weeks now of nothing, it looks unlikely. Maybe the answer will come in May or June of 2013 - wouldn't that be something!
Please let us know if you have any theories of your own or any comments below. We would again like to thank Frederic and his friends for trying to find Leri for us - here is the email he sent after searching for Leri at that central position on the Marigot a couple of weeks ago.
We went to the 'marigot de Khant', last 11th of november, with my friends Rozenn Le Roux and Cheikh Aïdara.
Aïdara and me walked in the marsh and looked for Leri and some indications.
Above the marigot: more eurasian marsh harriers than the 3th of november, one Montagu's harrier, one african fish eagle; and 6+ ospreys !
We did'nt find any body, line hooks or traps, anor any human presence as well crossing way of cows inside. Water level is everywhere from 15 to 30 cm, with many aquatic grass (level ~1m and more): in the middle of the lake, some water ponds without grass where caspian terns and ospreys can dive and fish (a lot of fishes but not big, usually catfishes). We found on the ponds, blocked by the grass, many little feathers and downs (ospreys diving !), and some grey herons feathers. Near Leri's lat signals in the swamp we watched for some tamarix senegalensis bushes in the water where Leri probably perched - especially a dead acacia young tree with many white droppings. When we walked (12-13h in the middle day) in the swamp, grey and purple herons, one black crowned crane and some spur-winged gooses (many joungs) flyed off. Where Leri was, 10 black storks glided at this time just above us !
A few meters from Leri's last data, a strange discovery: two places where grass had been made into a bed, with drops on: probably the bed of a Seba's python. There are numerous in the Bango's area. But we think it would be incredible that the big snake could catch the osprey ! By night ?
Our photographer took pictures of many of the ospreys we watched. I am going to send them in the next mail.
You can take others pics on my blog when the post will be finished.
We didn' see anybody (just cows drinking) and warthogs are very quiet... The hunter's season not began.
We think that Leri's aerial has a problem, and your nice female osprey alive, somewhere, between the others ospreys of the marigot de Khant, maybe elsewhere, now ?!
Kind regards.
Frederic.
Thanks for the update - still remain hopeful that Leri is alive and that the problem lies with the transmitter. I guess we just have to wait to see if anyone spots her and can ID her or wait even longer to see if she returns to the UK.
Many thanks for all the updates
Thank you so so much for this blog and also to our froends in Africa. My conclusion is that she is fine and it is a mechanical failure such as a broken transmitter. Remember this year I think it was Nimrod, one of Roy's scottish birds I had been following had a broken ariel spotted in Scotland so Roy would have no more date but have to wait until next spring to see if he returns to his nesting area to see if he survived another winter in Africa. Fingers crossed that in several years someone will spot he fying around Wales-ggod luck Leri.
Encouraging post indeed! From previous info I hoped the problem may be the tracker. The only post that bothered me was the mention of info of travelling at 1kph towards village-can't remember date.
So we continue to hope for the very best result-a sighting at some point - of your Leri :)
I also hope that someone somewhere may see my royal blue/White XL (right leg) over winter - maybe one day :)
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Thanks Dyfi for information, and huge thanks to Frederic and friends for the excellent information about habitat at Leri last known location. I myself have no theories which are better than the ones already suggested. I am a great believer in 'it's not over till the fat lady sings' so, unless there is definate proof that Leri is dead I will remain optimistic that she will be sighted some time in the future.</p>
What an encouraging post and a positive feedback from Frederic - I for one will now allow myself to think Leri has perished until a body is found. I still think the tracker device must have dropped off her, and that she is happily settled where there is plenty of fish and a nice tree to perch on. We must just wait and see!
No news is good news, as they say and besides Leri is Welsh and aren't they made of strong stuff. We will wait and see next year!
I feel after reading Frederics mail,the signs or should i say,lack of,sound encouraging.I beleive that Leri has a tracker problem and that she is out there some where.I guess like many others,i want her to be out there some where and more so,alive and well and thriving as a young Osprey should.I am optimistic that one day,we will all have a fantastic surprise and have good news of Leri.
Was happy to read a slightly more encouraging post today. We'll just have to wait until 2013 and hope that some eagle eyed watcher ~ sees her! x
Merci beaucoup Fredric & friends.
If this guys says he thinks Leri is alive that's good enough for me. No transmitter found, no body found, Ospery droppings at Leri's last recorded position. Keep the faith people !!
Ems & Team...PLEASE keep playing "We'll keep a welcome in the hillside" on the website until she does infact return home again to Wales.
The data points on your map look very regular. Visually each data/date point seems to have the same or similar angular displacement and each point also looks to be very similar in distance.
Could this be an indication that the GPS transmitter was breaking down and has eventually failed?
The manufacturers should hold data relevant to failure of their transmitters. Is this type of regular information a symptom of a known failure mode?
Despite all the statistics for losing chicks and trying to stay realistic - I genuinely believe she is still alive and that the transmitter was/has failed. Frederic and his friends are truly wonderful to take the time and trouble to look for her and their findings are postive.
Would be wonderful if we could send them some decent bird spotting equipment - I would be happy to contribute. Thanks to all the team x
My sixth sence is tweaking, has been since Leri's supposed disappearance, I know she is ok,,
I feel it's down to technology and the tracker is at fault,,
Fredric is quite right,,,dropping at the tree, no tracker to be found and no sign of a body or freshly pulled out Osprey feathers,,
I can't beleive a snake at night would take a bird as big as Leri is, there would of been signs of a fight,, fleathers or a drop or two of blood,, something,,
So,, as far as I'm concerned we will see our girl in 2013,
much love
Chrissy
XXXXXXXX
I share the view of most people, that this is a problem with the tracker: hopefully in spring 2013 Leri will be sighted somewhere in Britain. One point to think about, if the bird which Frederic saw (apparently with a tracker on its wing) was not Leri - which other could it have been? Are all the other British and European ospreys with trackers accounted for? It would be a remarkable coincidence to have two tracked ospreys in exactly the same location.
Many thanks to Ems and the DOP team and to Frederic and his friends for keeping us updated. It may be a long wait for any news.
Thank you once again for the update, fingers crossed for 2013, you never know!! but for now we can delight in seeing the antics of the boys.
Thanks Ems for letting us read the e-mail from Fredric. I think along the same lines as everyone else now and that the problem if the transmitter, possible the broken one that Fredric had spotted earlier on. I certainly think that Fredric sound so much more positive in theis e-mail. To me that sounds more like the explanation than any other. I personally think now that Leri is much alive and having a blast. Your never know maybe that transmitter may give off another signal soon with a different location altogether. Here's hoping we will all see her when she come back home.
Thank you Fredric for all that you have done in helping to find our Leri x
I think everyone has said everything I'd probably say. Maybe having three fully able chicks first time around is unusual? Did she meet her developmental milestones as quickly as Einion and Dulus? I don't think Roy said there was any difference between them. Amazing to think that we're all looking out for 2013 together. It would be so brilliant if she turned up. As an afterthought I'd love to have 10 black storks fly over me.
I am sure our Leri is ok!
I have not given up on her and something tells me she is safe and well :-)
Thank you Dyfi.
I was so sad to think that Leri was dead but this is giving me a glimmer of hope. Fingers crossed that we may see her again one day.
No. I haven't given up on Leri. I still like to think she's sitting by a source of fish picking bones out of her beak! We all know how frustrating technology can be at times. It may be good for two out of three chicks to survive BUT so too for all three transmitters. I wouldn't think it's fallen off as we watched Roy stitching them on and he's really experienced. There's always glitches with technology. Even the LHC at Cern didn't go smoothly!
Maybe its good news after all :-) Lets hope so. Leri always was a bit lazy, so it would be in character for her to use a central perch and not travel too far for her food. Many thanks Frederic & friends for your searches and for sending us all your findings.
Thank you for such an informative post. It gives us all hope, and thanks again to Frederic.
Looking forward to 2013!
Frederic, my dear, you are a saint for trudging out several times to look for sweet Leri!! My hope for her return remains steadfast and I look forward to seeing her fly over the Dyfi Valley in 2013. Dyfi Team, you rock!
Dear Leri, Your life has inspired and enlivened that of so many people around the world. Now that we know how nomadic your brothers are I am hoping to see a photo of you flying free and just with the band on. Beautiful girls don't like transmitters and you probably made quick work of it and left it behind so that you can pursue your life without the paparazzi. Your passion for life and spirit taught your brothers well, enriched our understanding of your species. May you be free and a bird that leaves these humans and their anthropomorphizing behind. go Girl go. You are always in my soul.