Kapa wrote:I have some questions to the experts:
- are the Estonian ospreys remaining in the breeding ground? That is: do they always come back to that area in spring or are they "opportunists" staying wherever opportunity arises?
- do the siblings recognize each other and will there be a rising rivalry or do they spread soon?
- will they fly to the hibernation areas on their own (just by instinct) or do they follow others?
Greetings,
Kapa
To answer your questions as far and as good as I can:
- Ospreys usually mate for life, but polyandry has been recorded. Only if a partner dies they will find a new mate. Ospreys are also very attached to their nest. So normally Madis and Piret will return to this nest next year.
For juveniles it's somewhat different. First of all, after they migrate south, they will not return next spring, but stay in Africa next summer. Spring 2014 however, they will return.
Male juveniles tend to return to the area where they were born, but when there are no vacant nests or nesting sites they will go look elsewhere and thus colonise or recolonise other areas (that's for example how Scotland became recolonised by Scandinavian ospreys in the 1950's after they died out in Scotland in the early 1930's)
Female juveniles are more flexible and more likely to stop on their way north wherever there's a vacant male with a vacant nest or nesting site.
- Right now the siblings recognise each other ofcourse and they 'talk' a lot among themselves. And I think they will recognise their siblings at least till they start to migrate. But I've no idea if they would recognise each other when they return in say 2 years and would meet each other.
From what I've read about other osprey nests there will be a fiercer competition among siblings for the fish delivered at the nest after they all have fledged. Has maybe also to do that just before they fledge they catch fish themselves sometimes, and I can imagine that this selfcaught prey is defended hard.
Here an example of such a fight about a fish between two fledglings:
http://www.youtube.com/watch?v=P-UvnnygxSw
- Ospreys migrate individually and by instinct. From the British population is known that satellite tracked osprey siblings follow different routes, but somehow manage to make 'pit stops' at the very same spot, only at different days. On one occasion an osprey left a spot in the morning, and late afternoon the very same day his sibling landed on that very same spot to spend the night there.
I wonder where the members of our family will spend winter. Finnish ringed ospreys have been found as far south as South Africa, and a Norwegian ringed Osprey was found in western India, while other Norwegian ospreys migrated to West Africa.
and didnt notice, that there are more than two birds fighting for the nest 
Kulkelke
