|Time in Flight:|
Leri was the surprise chick of 2011 - she hatched out of the third egg when we all though this egg was infertile. Leri is a bit of a madam, she's feisty and extremely bossy. She formed a close bond with her brother Dulas but it was obvious which of the two wore the trousers in the nest. Always ready to pick a fight, she certainly stood up for herself with two older brothers around. She is named after a tributary to the Dyfi River where Monty fishes.
Latest News for Leri
Leri is quite an enigma. From the very moment she clambered out of her egg on this day last year, she has been full of surprises. The fact that she hatched at all was puzzling given that the incubation times of the eggs last year were so late. Here is the first sight of Leri we ever got on June 7th last year - the other two little ospreys you can see to her left are her brothers, Einion and Dulas.
Leri grew up to be a feisty, food loving osprey with an attitude. She took no prisoners and always stood up for herself, often ending in squabbles with her older brother Dulas. She was the last of her family to migrate on September 13th - Monty had left two days earlier, 408 fish caught in a season was enough for him. Leri missed the worst of the storm that blew Dulas off course the day before, but she still got caught up in some strong winds. Instead of heading south she was blown south-east and flew directly over Chichester before starting her channel crossing over Bognor Regis.
Leri (looking this way) with her two brothers in her Dyfi nest, all three chicks beautifully camouflaged.
We had high hopes that Leri would reach Africa safe and well. She weighed 1610g when Roy Dennis and Tony Cross weighed and ringed her on July 19th - a good healthy weight for a female osprey that age. Her Darvic ring was put on her right leg (left leg in Scotland) - Blue DJ.
Leri and her two brothers being ringed and tagged in 2011
Roy confirms that Leri is in excellent condition at six weeks old.
It was no surprise then that in just two weeks after leaving the Dyfi estuary, Leri had flown over 3,000 miles and had reached west Africa. She was, however, 450 miles inland so over the next week and a half she slowly but surely flew west, heading towards the Senegalese coast.
Then, on the last day of October 2011, her transmitter stopped sending signals back. Our friend Frederick who lives in St. Louis, Senegal, spent many days looking for Leri last November and December but to no avail. There was nothing to be found where the tracker last sent it's transmission. We simply did not know whether the tracker had stopped working or whether Leri had died. Then, six months later, the most unusual thing happened - Leri's tracker started sending signals again - from America!
Could Leri have flown all the way over the Atlantic over the winter?
The signals started showing up on April 12th and were coming from Maryland, USA. We were thinking all sorts - boats, ships, oil tankers (its happened before), floating wood. Surely Leri could not have made it that far over the ocean - then it dawned on us. The position of the tracker was exactly in the same position as the laboratories where they make the 30g osprey trackers. A quick phone call to Microwave Telemetry, who make the units, confirmed what we had been thinking. Leri's tracker number had been deleted and re-assigned to a brand new unit which was being tested for solar efficiency on a sunny Maryland roof. It wasn't Leri at all, it wasn't her tracker either. Back to square one.
Then, around a month ago, we started getting more signals, this time from Africa. In fact, they were coming from the same area that Leri was at when she sent the last transmission all of those months back in October. They were poor quality signals to start with - many showing 'low voltage' and 'low battery'. Then the signals got stronger and stronger until they were sending proper data about position, altitude and speed. Is Leri still alive?
Leri's tracker has been sending valid data since mid May, what does this data mean?
The GPS points show movement, not much, they are all within one square mile, but movement nonetheless. There also seems to be two or three main locations within the scatter of points where the tracker seems to go back to time after time. If Leri was dead, why would the tracker (a) keep moving around and (b) return to two or three base points?
The data, actually, invites more questions that it does answers. Would an osprey really be in the same spot as she was eight months ago? Why isn't she moving more than a few hundred metres (800m maximum from the centre). Why has the tracker suddenly started working all these months after quitting? Has the return of the rains turned the tracker over, pointing it back at the sun again? Have a few feathers on Leri's back moulted and exposed the tracker to sunlight again?
We have just published these GPS points on Google Earth for the first time this evening - please feel free to have a look and tell us what you think (Google Earth help here). Press each GPS point for information specifically about that way-point. Look at the distances involved, the timings and the altitudes. Finally, try and be objective. We all want Leri to be alive, but we also need to be realistic and try to get to the truth. Maybe the truth is in the data - if it is, we can't find it. We will now continue to update Leri's GPS points on Google Earth - they come in every four days at the moment.
Leri continues to be an enigma. Maybe one day we will know one way or the other what has happened to her. For now, and for the last time this week,
Happy Birthday - Penblwydd Hapus Leri
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 ?!
It is now a week since we've had a signal back from Leri. It's come to that horrible 'inconvenient truth' time when we have to say that Leri has most probably died.
It didn't look good a week ago when her transmitter was sending back signals with a recurring 'activity reading' number meaning that the transmitter wasn't moving from one place to the next.
This '110' number is randomly generated and should be different for each position
On October 22nd Leri started to move south from the area she had been in for around two weeks, on a tributary of the Senegal River. By the 24th she had flown around 12 miles south and was in the Three Marigots water system near Mengueye. It was at around 4pm on the 24th that we think she got into trouble.
Leri's transmitter weighed just 30g and was state of the art technology - these trackers didn't exist just five years ago even. Yet, for all their incredible data gathering capabilities, one thing they cannot tell us is the condition of the bird itself. Was Leri getting weaker as she continually looked for better fishing grounds? We know that a lot of these water bodies and tributaries dry up at this time - well established ospreys have acquired the best fishing spots and will out compete this summer's juveniles. Frédéric's recent email states that he saw eight or nine ospreys in this area a few days ago, most of them juveniles - it seems clear that this area is not preferred by adults. Frédéric also mentions old fishing nets and hooks in the water within this area, could Leri have got caught in these and perished? No meaningful data came in for October 25th and 26th but the activity number reading was not changing, still showing 110. The last confirmed GPS readings were sent on October 29th with some other data on the 30th. Nothing has been sent since.
The statistics are known, only one in three or four ospreys ever make it back to the UK to breed. By 2011 the Glaslyn osprey nest, just 28 miles away from the Dyfi nest, had produced 12 fledglings that were old enough to have returned to the UK, yet only two have so far been spotted. Yes, there maybe others that we haven't managed to identify but it still looks no better than one in three/four probably. We are learning all the time of course, this is the first time that Welsh ospreys have been satellite tracked, and we already know that being so far west probably does not negatively affect their initial course and predispose them to fly west into the Atlantic, something that we had worried about for a long time. We have also learnt from this and other osprey tracking projects in the UK that the success rate of the first migration to west Africa is relatively good; in many cases it's the increased dangers the birds face once they reach their final destination in Africa during their first winter that seems to be the bigger threat.
Knowing the stats and applying science to Leri is fine but it still does not take the hurt away of course. Protecting those three eggs in April and May with a team of dedicated volunteers 24 hours a day for six weeks, watching Leri hatch live on that magical Tuesday in June, and then grow up and fledge before finally migrating on the 13th of September, the last of all the family to go, is still hard to take. Roy Dennis has just arrived in Senegal and will concentrate now on trying to find and film Leri's two brothers Einion and Dulas. The boys seem to have found better fishing areas and look settled. We hope he finds them of course, will they be in good condition?
The Montgomeryshire Wildlife Trust would like to thank all of you for your interest in the Dyfi Osprey Project particularly during the last week with all of the concern over Leri. We would also like to thank Frédéric for all his hard work in trying to find Leri for us. Merci Frédéric.