White-tailed Sea Eagle Questions

[bielikoholik]

Thank you for the reply.
Remains for us only to wait...
In Poland white-tailed eagles recently aren't also willing for nests with cameras...

[ame]

all eggs will not hatch. this has happened a few times also in front of our cameras both in WTE but also on other nests. this spring it has happened in the Latvian black stork nest where two eggs have failed.
an event like this always raises questions about reasons.

Yarko has found a good page with a lot of information on this subject. the page is involved with bald eagles but the information undoubtedly applies, at least in general, to other bird species, too.
http://raptorresource.blogspot.fi/2016/ ... hatch.html

keyword searchhatching.

[tara]

I wonder how much more the female will be tired in mind next nesting, when she has now three cubs. Will Anna get tired

[ame]

i don't think that Anna will get more tired now than if she had only two or one or no eaglets at all to take care of. both parents will have a rather leisurely autumn and early winter. -this is of course my personal feeling only. i don't know if there's any research on this subject. i doubt it.

[tara]

Thanks, ame

[EveningSun]

I have a couple of questions about WTE.
1. When eaglets became grown-ups and leave a nest for good, do they remember each other or their parents?
2. Is it possible that brother and sister would start a family together?

[ame]

good questions, Eveningsun. i have sometimes thought about a question which could be added on the list.
3: will the eaglets remember their home nest after they leave it?
i'm afraid that no-one knows answers to these questions for sure.
instead of firm answers i can write down some reflections about these questions. you may then judge for yourself how plausible my thoughts and guesses sound.

i should think that as relatively highly developed animals eagles must have rather good memories. they also live long (if they survive their youth). i think they'll remember what they learn during their lives. the surroundings of their home nest the WTEaglets will learn to know rather well as they don't fly away for good like LSEaglets who fly away for good on the first time. even small migrating birds are known to return to the same nest (box) for breeding year after year so why not bigger long-lived WTEs wouldn't remember and know their nest if they happen to cruise around. - they'll not be welcome there if their parents still occupy the nest.
at the old Saunja nest in 2009 a young 1st-calendar-year eagle once sat on a branch by the nest for a very long time when Linda was brooding. we then suspected that this young eagle could have been Linda's and Sulev's eaglet from the previous year, but of course there was no way to know it for sure.

we have seen in the winter feeding ground and on the seal island that, despite being very territorial, WTEs are also fairly social animals: outside the breeding season they gather in flocks to places where food can be found. i think it is quite possible that for example in winter gatherings eagles might learn to know each other individually so that they'll recognize each other if they happen to meet again later somewhere else. eagles know their own spouse so why not would they be able to recognize also other individuals.

when i watching the winter feeding place i had a few times the feeling that there was a whole eagle family there: a young 1st winter eagle eating while an adult stood nearby and looked at the young eagle eating (a reverse pecking order). in eagle books i have also read about eagle families feeding together in the autumn. so eaglets will learn to know well how their parents so why wouldn't they remember them later?

will it also go the other way round i can't quite even guess. the appearance of young eagles change so radically while they mature that maybe parents will not recognize their offspring after a few years. probably siblings will loose track of each other, too. they are known to fly different ways after leaving their nest. then it might be possible that a sister and a brother could start a family later in their life. this is even more possible if the siblings have hatched in different years. in that case they would have (besides naturally the parents) nothing else in common experience than probably the same nest.

[EveningSun]

Thank you, ame! These are very interesting thoughts.

[hennabauhaus]

There is only 1 egg now, before there was 2, am I wrong?

[ame]

yes, there's only one egg left now. the other broke a few days ago.

this question actually belongs to the Est WTE topic i think.

[Konrad]

A question about the functionality of the talons.

It often seems to me that an eagle − or as well an osprey − cannot open its ”fingers” always, when it wants to do it. Especially, when a parent bird brings food.

We know biologically, that the leg of a bird is very tight. Not many muscles and no fat.

Is it possible, that the talons are controlled more by the autonomous nerval system than the own will of the bird?

[ame]

oh dear, this question is too difficult for me to answer.
i hope that one of our specialists will see it and will provide an answer.

all i know is that the claws/talons lock automatically around a twig or a stick when a bird goes to sleep on a perch. that must be involuntary. on the other hand we often see how the eagles use their claws to scratch their cheek very close to the eye without any risk of hurting the eye. in those cases they must be very well in control of the movements of the claws.

[Konrad]

Sorry Ame, but I am here again with a difficult question.

In this season at Sulev’s and Suvi’s nest, we have seen Suvi behaving like a nestling, when Sulev brings food to the nest. Even pecking Sulev.

Does anyone know, why the eaglets (and in this case, also the possible teen-mother) start to behave aggressively against the male parent?

In human thinking it seems strange, that an eaglet starts to shout to and even attack the male, who brings food to it.

Can it have something to do with the fact, that the adult female has spent more time than the male with the eaglets in most nests, which have been watched? So, as the eaglets start to get adult and start to think about every other eagle as an enemy, that a bit more seldom seen male is the first ”enemy”?

Perhaps we will see different behaviour in this nest, because the male has been in the nest more than the female? Just my guess, that Sulev has spent more time there.

[ame]

hi Konrad!
you have again asked questions to which probably not even experts can answer reliably. i think that we can only watch and guess for reasons.

one thing is rather obvious to me: the eaglets are so greedy that all they can think of when they see food coming is "ME! MINE! MY FISH!" then they rush to grab the fish. the hungriest/strongest eaglet wins if there are more than one. the father eagles know this behaviour and escape the nest as quickly as they can. the average duration of the delivery is around 2 s.
this is actually not aggression, it is only figth for the survival of the fittiest.

it may be question of something similar when the mother eagle grabs and takes the food that daddy brings to the nest. she is defending the chicks. this is only my guess though.

I have watched Sulev in the old times. i remember how he enjoyed spending time with his chicks, with Illimar especially. he also fed them every time Linda let him to do it. this happened when she happened to be away. now i'm watching the J-E nest in Latvia. there the male Raimis is very willing to feed the babies. for him it took a little longer to learn how it's done. also Milda the female had to learn this trick. we believe that both are breeding for their first time. Raimis also like to stay with the chicks, now that Milda lets him stay at home. first she was very jealous of the chicks and could not stay out. she kept coming back with bigger and bigger sticks and in the end Raimis believd he and left.

[mogga]

Konrad

Just some thoughts by me:

Pecking of young birds at their parents I often saw at other nests and also among the birds in my garden. This pecking concerns the male parent as well as the female parent. I am doubtful whether their is a great difference in frequency towards the male adult.

Suvi's pecking at Sulev can also be watched with the ospreys (Irma pecking at Ivo). I can imagine lots of possible reasons for this pecking, maybe some of them aren't even an aggressive behaviour but they occur for other reasons. You see, I don't really know, too...

[ame]

...
Suvi's pecking at Sulev can also be watched with the ospreys (Irma pecking at Ivo). I can imagine lots of possible reasons for this pecking, maybe some of them aren't even an aggressive behaviour but they occur for other reasons. You see, I don't really know, too...

exactly: pecking can also mean kissing. it's often difficult to see if it is question of negative pecking or positive kissing, at least for us humans. even the male is often puzzled. it is always a good idea to be careful when a huge beak is approaching one's eyes.

[Konrad]

Pecking of young birds at their parents I often saw at other nests and also among the birds in my garden. This pecking concerns the male parent as well as the female parent. I am doubtful whether their is a great difference in frequency towards the male adult.

Thank you for your answer, Mogga.

At eagle nests that not-so-polite pecking and also other forms of aggression has happened only towards the adult males.

Perhaps we will see something different this year in the Estonian nest?

But the question remains open: why do the nestlings start to behave aggressivly against their parents?

[ame]

7:20 an interesting episode at the Latvian nest: the smaller chick Vilnis bit his daddy's foot when he was taking a step away. perhaps Raimis happened to touch Vilnis with one his claws.

this was also interesting because Konrad has made some questions about the aggression that eaglets seem to pose against their parents, especially the male. i believe that usually the behaviour which Konrad refered to is not actually aggression. this seeming 'aggression' takes place when the parent(most often the male) brings food to the chicks who are already rather big. they are so greedy that they try to grab the food at once from the male's claws, before the sibling gets it. i have watched this many times and i have seen that the eyes of the eaglet are nailed on the food and they don't pay any attention to the male. it is merely an accident that the male's claws are still locked on the fish when the eaglet grabs it and often (by accident) also happens to bite the male's foot. the male is prepared to this behaviour and leaves the food and takes off from the nest as quickly as possible. the shortest deliveries last less than 1 second, on the average about 2 - 3 s.

this reaction by Vilnis was maybe due to the stress and frustration that he has been suffering when his bigger sibling has beaten him. he now punished daddy when he is afraid to hit the bigger sibling back.

[raija]

I have tried to find information about what happened Nord Rahu and Taibu after the year 2016, but I have not found. Would anyone tell me about their phases. Of course, Anna and Uku are also interested.

[ame]

hello Raija and welcome!


no-one knows about Anna's and Uku's family, except that the parents are staying in the same territory if i remember right. (i'm not absolutely sure though..? )

the eaglets have flown their own ways. if we are lucky someone will spot them somewhere and capture a picture of their rings. so far we have later sightings of 2 eaglets out of 8 Estonian eaglets that we have seen growing up. i have not heard any news about the 3 Latvian eaglets.

the 1st-year survival percentage of any bird species is not high. WTEs are no exception. it is roughly estimated that 50 % survive to see their second summer.