For those who are interested in osprey 'ancestry'.............
With regard to Sue C's post: of 19th March 2011:
2003 EJ lost her nest to a more aggressive female,
The female in question was Green 7B. EJ had laid eggs and, having seen off EJ, Green 7B bought in nesting material which she placed over the eggs. Green 7B was unsuccessful in breeding that year - but in 2002 she had (as a 2 year old) arrived late at the Loch Garten nest. There had been many disputes between male ospreys at Garten that year as the male osprey (Olly) who had 'reigned supreme' for many years had not returned. Green 7B persuaded the conquering male to feed her, but did not produce eggs.
Green 7B also had an ancestral link to LG - she was Olly's grand-daughter.
Some people think Ospreys are a matter of life and death. I don't like that attitude. I can assure them it is much more serious than that.
Interesting about the trout.
I seem to remember 60 miles being mentioned with regard to the Finnish ospreys.
Yes, we know very little about anything really.
ChloeB & Tiger's Osprey Data
TIGER has suggested that I ask here the Q. that I posted on Feb Chat thread.
I was reading through all the data from 2003 onwards and was wondering whether any theories had been voiced as to why no chicks were reared in 2007... 2 dying at only a day or 2 old and the third dead in the egg.
This is a fascinating and thought provoking thread. Thank you everybody
Wasn't 2007 a second clutch - after Henry arrived late and ejected the eggs already laid? As far as I understand it, that is incredibly rare in itself - maybe only the 2nd or third recorded second clutch in the UK? So the birds are only physically geared up to produce 3 eggs - or at most 4 - in one season, and maybe these just weren't strong enough to survive. It is perhaps surprising that they hatched at all.
They would also have hatched very late in the season - could it just have been too hot for newly-hatched chicks? Can't remember now what summer 2007 was like!
Have to echo what others have said re CRinger's contributions - it is absolutely fascinating to have your 'behind the scenes' insights - many, many thanks!
Here is the video of Henry kicking eggs out of nest in 2007. It is a somewhat confusing video.
Also see Jealous Osprey's Egg Incubating
also Henry's Cracking Return and Henry the eight I am, I am!
I believe that the latest date for osprey eggs to be laid in Scotland since 1954 is about 22nd May. Hard to tell whether the pre-1916 birds laid later. I got the feeling from "Scottish Ospreys" by Philip Brown that ospreys did lay later then but that might be wishful thinking.
Tiger Signature
This is an absolutely fascinating thread and I have learnt so much and enjoyed reading.
Thank you CRinger for starting it and all others for their contributions.
Fascinating video's Tiger.
Thank you all and will continue reading but cannot contribute as so much to learn :)
I agree B&B..
Thank you all so much for sharing your knowlege.. you are really bringing the new season alive for me.
All for one and one for all.
Hi Patily
Another interesting question and I think that 'theories' is correct, we can only speculate. My best guess is that Rachel may well have hit the nail on the head when she suggests that normally females are only geared up to produce 3 or 4 eggs. If they have to produce a second clutch then, to me, the chicks hatching may well not be strong enough to survive.
I think that there is supporting evidence for Rachel's theory.
If you look at the average number of fish brought back to the nest each day from when both male and female have arrived from migration you see a gradual increase in fish numbers. It peaks around 41 days prior to hatching of the first egg. It peaks at almost 3 fish each day. Then fish numbers start to decline.
At least 2 points of interest here, I think. Firstly, the female may or may not have had an arduous migration, but she certainly will invest a lot of energy in the production of eggs. A well fed female is surely likely to produce 'better quality eggs' = better quality chicks, than a female whose partner is not particularly good at acthing / delivering fish.
Secondly I think the 41 days prior to hatch is significant. As the mean incubation period is 37 days, this suggests that the male reduces the number of fish back brought to the nest around 4 days prior to laying of the first egg. If you have a look at my post of 25 Feb you will see that I suggest that the female is possibly at her most fertile about 4 days prior to laying her first egg. Her mate, by reducing the number of fish he brings to her at this time is therefore able to spend more time at the nest at this critical stage - to ensure she doesn't mate with any other male. In addition, if you look at the average time the male osprey is away from the nest catching a fish - forage time - amazingly enough the male's mean forage time decreases around 6 days prior to laying of the first egg, then starts to increase again 2 days after she has laid. It could therefore be argued that not only, at what appears to be a critical point of c. 4 days prior to laying the first egg, does the male reduce the number of fish he brings to the female, but he is also faster at bringing back the fish he does actually catch.
Returning then to the number of fish brough back....... it reduces around 4 days prior to laying of the first egg and remains pretty constant (at about 2 fish a day) until the first egg hatches. I accept that during the 'pre-laying period' a female osprey may be more active (gathering nesting material) than duing the incubation period, but it seems logical to me that a female who has been incubating and living on 'reduced rations' of a share in 2 fish a day, will be unable to invest as much energy in a second clutch of eggs as she would have invested in her first clutch when she was having a share in almost 3 fish a day. Logic then suggests, as Rachel says, that the chicks from a second clutch may therefore be just not strong enough to survive.
CRinger thank you for sharing you knowledge it is quite fascinating. I am intrigued by the behavours of the birds particulary when the season does not follow what is expected. We saw/read on the LOTL site about the frustration nest, which the female had nothing to do with, and allegedly on her departure the male mating with a new female on that nest. The latter was never confirmed by LOTL themselves. In these instances if all 3 return does the male tend to favour the old nest and female or is it the new relationship that is victorious. Presumably two nests in close proximity would not work?
Hi Lmac. I think there are really 2 questions here. 1 is about relationships, the other about nests. Dealing with the r'ship question first, I don't know what happened at LOTL which resulted in the frustration eyrie being made. I do recall tho' that at LG 1 year the regular female was late arriving back, by which time her mate, Olly, had found another female. That year Olly and his new female joined forces and drove off his old female. I suspect that may have been because his new female was already sitting on eggs when the old female returned, so he had already invested in his 'future' that season. I'm not sure what Olly would have done if his new female hadn't laid when the old female returned. As a a matter of interest I think it was this new female that disappeared in early July either that year or the next, entangled in fishing line and was presumed to have died.
As to close proximity of nests I had understood that Scottish Ospreys, unlike the carolinensis sub species, nested in loose colonies, but that individual nests were usually a number of km apart. However, I then saw 2 scottish Osprey nests within 300 m of 1 another. I believe that the first year both nests were occupied both pairs successfully reared young, but in subsequent years there was many 'territorial disputes' as a result of which 1 of the nests was either unsuccessful or unoccupied. Perhaps the tolerance of individual ospreys to proximity of other nests varies between individuals. I have certainly witnessed individual ospreys behaving differently to other bird species, proximity of humans and most interesting of all, other ospreys. Perhaps there is more 'individuality' in these birds than many of us think.
CRINGER Thank you SOOOOO much to your response to my query. A fascinating and thought provoking read......Thank you for taking the time to write such a lengthy and well explained response.
Thank you too RACHEL. It would seem that the reason you and CRinger give for the failure of the second clutch, makes perfect sense......and sad as it is trying to raise the chicks, even if they survived a while longer, might have a detrimental affect on the adult birds', especially the female, on their own migration south.