Satellite Tagging

Loch Garten ospreys

Loch Garten ospreys
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Loch Garten ospreys

Satellite Tagging

  • Now, after  losing Tore too, several people have shared their opinions "both for and against" tagging . 

    Someone suggested we collect the  views and "stats" on the  survival of tagged birds and bring them to the attention of Roy Dennis at his next talk and ask his opinion 

    With a separate thread, all the  comments  will be in one place for  whoever speaks to Roy. 

    Rachel provided  some sobering stats yesterday on the survival of tagged juveniles  verses the survival of   juveniles with just leg rings  and  I hope she puts those stats here too 

     Originally I  thought the information obtained from the tags would  be  valuable for insuring the survival of the Osprey.

     Now I see  that all that is being learned is  where they go and that they have  perished. :(

    They learned that all 2 year olds (Rothes) do not make a complete migration the first time, but  is that information worth £3000? 

    I don't know if the tags are contributing to the  death of these birds and I don't want to speculate.

    However, the cost to tag them is tremendous . Would the money be used more wisely to train more people  who are licensed to attach leg rings so  more  juveniles  would have  rings?. Could the  money be used to send Roy, Richard and others "more often" to the places where they winter to educate the locals on how to  protect them? Maybe they could give pre-addressed postcards  to   the locals at wintering sites to  report  leg ring sightings or other news of interest? 

    Many   people here  who have vast knowledge of Ospreys  have  great statistics on many birds "just from their leg rings" .

    Perhaps a  three year experiment with only legs rings would be  helpful to see how many  juveniles  with "only" leg rings return in 2-3 years 

    I personally think the  leg rings are  very valuable 

  • Thanks for starting this thread, Barbara.  I really like the idea of a three year leg rings only experiment.

  • I think this extract from the Rutland site might help .

    "After fourteen years and 75,000 miles of migration between Rutland and Senegal, he finally had a chick of his own. It is moments like this that make all our years of hard work at Rutland Water, worthwhile. 1998 was my second year on the project, meaning I have known 09 for all but a few months of his life. Having watched his repeated failed attempts to breed and then followed his amazing migration from Senegal, watching him looking down into the nest at his first newly-hatched chick was a very special moment indeed.

    Although we do not know how many eggs are in the nest, 09 is likely to increase his fishing effort now his first chick has hatched. We’ll be able to monitor every fishing trip using his satellite transmitter and it will be fascinating to see how the arrival of the chick changes his behavior. We’ll be sure to keep you updated over the course of the summer, but for now just raise a glass… to 09 and success at last! "  

    The full article mentions the loss of three birds,presumably shot locally, which makes the tagging of this one even more significant.

  • Mike, thanks for the quote from Rutland. I think there is a distinction to be drawn between birds which are tagged as adults and those which are tagged as chicks before they fledge.  Both the example you quote above, and birds such as Red8T, Morven, Beatrice and Nimrod tagged by Roy D as adults have provided a lot of data, and there appear to have been fewer casualties among that population. Rutland AW was also tagged and may have been lost but this is a more isolated instance.

    The concern I have which is demonstrated very well by Rachel's data relates to the return of juveniles tagged prior to fledging. I now feel very uncomfortable that the rate of loss of these (mainly highland) birds seems greater than the Rutland population which are ringed but not tagged. Rutland have the advantage of one organisation monitoring a group of nests, and they are very good at reading the ring data from intruders to identify returning chicks, so there may also be an impact from the data collection on the apparent return rate. Many people thought the "handsome visitor" at LG a couple of weeks ago may have been an LG chick, but as the 2010 brood were not ringed (for good reasons) we will never know.  Both in terms of cost and impact on life expectancy, I do now doubt the overall value of tagging fleglings.

  • When we talk about juveniles the first thing we need is some statistics on how many go south each year and how many are ever seen again. I doubt that we ever see fifty again othewise the osprey population would be exploding.

     Then we lose expeienced adults too. What happened to green 7Y?   The Wigtown ospreys and how many others that we do not know about.

  • You're right in that Tiger,

    This sort of makes tagging/tracking pretty much a one way street, with an occasional "driver" coming up the wrong way..

    A bit of a lottery, then.

  • I think that the reasons that tagged adults seem to do better than juveniles is that they are a self selecting bunch. They are birds that have managed to find safe areas in Africa. We know that the adults move very little when they reach their winter quarters. Thus if they have found a safe area then they stay safe.

  • Here are the numbers of ringed young ospreys supplied by the BTO:

    2008 148

    2009 194

    2010 182

    2011 164.

    How many of these have returned?. Very few I suspect. Tagging or not I think the birds would have perished regardless. There are a lot of dangers in Africa apart from shooting. fishing netting, crocodiles, hyenas etc.

    Despite the doom and gloom, overall sightings are up this year particularly for May indicating that there are a lot of young ospreys around looking for nests.

  • Alan Thanks for that data.

  • Hello Alan,

    Thanks for that info, yes I agree, from the sightings you post of migrating birds it seems that numbers are good.

    The doom and gloom is, for me, caused by the trackers.

    If Tore and Bynack were not tracked I would be living in blissful ignorance to the fact that these birds were dead. As I am with the "Born Free" Three from LG 2010.

    However as I said on the Gab last night, if their demise helps us understand how or why, then it is one up side. Now if we are seeing one particular area of danger for the birds, we may be able to target that area with an educational programme.

    There must come a time though that we are learning nothing more from giving birds "schoolbags" to carry.

  • Yes Alan, it is good news that there are a lot of young ospreys around looking for nests, a lot of un-tagged young ospreys you forebore to add.

    I am strongly of the opinion that tagging young birds is unnecessary and probably detrimental interference to their well-being. As Barbara said, tagging is an expensive business and the money could be better spent elsewhere in pursuit of their welfare and conservation.

    We have learnt interesting things from being able to follow their migration, but enough to justify the expense in financial terms or to the birds themselves? I think not.

  • I agree with Tiger about the tagged adults.  I am however very worried now about the youngsters.  I  feel that tagging was a good thing, and we have learned a lot, but maybe if things don't improve over the next couple of years, ringing the young and tagging the adults might be a better way to go.  Seems to me the youngsters need all the help they can get!

  • We shall have to agree to disagree Rach. Until its been proved that a backpack (harness or aerial) has caused the demise of an osprey, I will always be of the opinion that they have no effect whatsoever on the survival of the young ospreys. Look at Rothiemurchus and how well he has done ranging hundreds of miles up and down the country and now returning for a second year.

  • Can anybody tell me please, whether there is any further particular data that it is hoped will be gained by further tagging of youngsters? When was the first tag used on a young bird?

  • patily

    Can anybody tell me please, whether there is any further particular data that it is hoped will be gained by further tagging of youngsters? When was the first tag used on a young bird

    I dont know if this, from the old Rutland site, helps but I think it is about that time. I recall being there and seeing the tags when the first batch arrived prior to fitting.