This thread is a total experiment! I thought of it because a few nights ago, a lot of of useful information about ospreys was being posted in the LG Diary comments, but because of the blog format, it will be out of sight once a new blog is posted, and easily forgotten.
The idea for this thread:
· To provide a place for people to ask questions about ospreys at Loch Garten, or ospreys in general, which members of the Forum will answer to the best of their ability. NB Questions directed to the team at Loch Garten, should still be posted in the Comments area of the Loch Garten Osprey Diary.
· To preserve the answers for future reference
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Sue C Do you know if the parents of EJ were ringed. Just wondering if there is a remote link to female near me. She was ringed in 1994 - right leg royal blue/XL white & is believed to have nested near Bridge of Cally since 1997.
I know its a long shot but worth a try!
Thanks
Val
One Life - Live It!!
Val The info about EJ hatching near Bridge of Cally was drawn from Roy Dennis' book "A Life of Ospreys" and it says no more than I've said above. The people who would know, would be Roy and Keith Brockie, who I believe still does the ringing in the area - I remember him posting on the LOTL blog last year.
Keith Brockie posted just yesterday over at the LOTL Facebook group.
Tiger Signature
I'm using this thread to continue a discussion which started on this thread, around the following question:
What is known about the behaviour of sub-adult ospreys (age 2) and young adults (age 3 up to first breeding)?
If you were taking part in the earlier discussion, please feel free to copy across relevant posts.
It's worth reading this page from Roy Dennis' website, which mentions some relevant points explained in greater detail in his book "A life of ospreys"
In particular:
Both of these factors are obstacles to ospreys colonising new areas - though obviously there are real-life exceptions, or nests like the Welsh ones, Bassenthwaite and Kielder would not exist.
1. How much time would it usually take for Rothes to get back to the LG area? Providing she doesn't have an extended stop over somewhere
2. How often has Roy or any ringer been wrong in guessing the sex of a Juvenile? I ask this because I expect some one to see Garten and I still think he is a male. :)
Formerly known as Barbara Jean
Unknown said: 1. How much time would it usually take for Rothes to get back to the LG area? Providing she doesn't have an extended stop over somewhere 2. How often has Roy or any ringer been wrong in guessing the sex of a Juvenile? I ask this because I expect some one to see Garten and I still think he is a male. :)
Hi Barbara Jean,
1. If you look at the days Rothes was actually travelling on her way south, she took 6 days to fly from LG to the Gironde, a further 8 from there to the Senegal river, which she was nearing in Caroline's last report, and then 3 to reach the Bijagos Is. So in theory a fortnight from now, though there would probably be a stop at some point.
2. As I understand it, juveniles are sexed on the basis of weight, wing length and other key dimensions in relation to their age - because females are heavier & bigger. Some mistakes have been made - for example I think I'm right in saying that Black 80, the male now breeding at Threave Castle, was thought to be female when he was ringed at Glaslyn as a chick. If you look at this report of the ringing and tagging of the 2009 chicks, Garten would have been pretty heavy if male - though she was known for her appetite!
1. If you look at the days Rothes was actually travelling on her way south, she took 6 days to fly from LG to the Gironde, and a further 8 from there to the Senegal river, which she was nearing in Caroline's last report. So in theory a fortnight, though there would probably be a stop at some point.
2. As I understand it, juveniles are sexed on the basis of weight, wing length and other key dimensions in relation to their age - because females are heavier & bigger. Some mistakes have been made - for example I think I'm right in saying that Black 80, the male now breeding at Threave Castle, was thought to be female when he was ringed at Glaslyn as a chick. If you look at this report of the ringing & tagging of the 2009 chicks, Garten would have been pretty heavy if male - though she was known for her appetite!
[/quote]I understand that if the weight/dimensions are high it can be certain it's female if it's low it's definitely male but there is a band in the middle where it's a bit uncertain. I'm sure I've seen reports where Roy Dennis said he couldn't be certain but suspected.... However there weren't any uncertainties reported with Garten.
What were the details that led you to believe she was male?
Even as full grown juveniles Garten looked quite a bit smaller.
Following Rothiemurchus's travels to Orkney a Question for Discussion: Is this movement North of the natal site the norm? The four Juvenile Osprey's I'm aware of that have been tracked have all travelled in a Northerly direction past their Nest site. Rutland bird 06(01) was tracked to N Yorkshire before the transmitter failed; Mirja moved off North West four days after arriving "home"; Buck was last reported travelling around Virginia (350 miles north of home) and now we have Rothiemurchus making similar northerly movement.
There are probably others that know of examples that go against this but are we likely to find this northerly movement is a common event? I give links to the 3 websites below:
http://www.zen88810.zen.co.uk/ROspreys%20site/Bird%20U06.htm
http://www.luomus.fi/english/zoology/satelliteospreys/2002/mirja.htm
http://www.bioweb.uncc.edu/Bierregaard/maps11/buck2011.htm
Vespa Very interesting thoughts. It will take me a while to think about this idea.
If you look through Rob Bierregarrd records he found that adult females often went on excursions if their nests failed. Sort of similar.