Latvian WtE nest webcamera Juras-erglis: Discussions

[Ajeta]

a question about the tail marks
do you really not see any difference for example in these tail patterns?
...
i look at the tails a little like pictures in an inkblot test (Rorschach's test).

Milda and Raimis - especially in the pictures you chose - probably represent the ends of the spectrum within which adult tail patterns commonly appear.

Most of those strangers we saw, however, had tail patterns much like Raimis. That made it a little more difficult to decide whether we saw different eagles or the same.

E.g. the tail of the present stranger as depicted on an earlier visit (i.e. before he became the resident stranger) here (picture by Ame):

https://www.looduskalender.ee/forum/vie ... 06#p787606

was taken to be the same as this stranger's tail (picture by Nordri) Edit (after Ame's post below to avoid further misunderstandings) who visited the nest on March 31st and was henceforth called Mr X:


https://www.looduskalender.ee/forum/vie ... 29#p785529

Accordingly reporting assumed wrongly that the stranger who appeared on March 31st stayed with Milda until April 8th (when driven out by Mr C).

A closer look at the tail as well as at the eagles themselves would have allowed to see that there were enough differences between them (distribution of light and dark feathers on the wings, general appearance, head etc.) for them not to be one and the same eagle. Unfortunately those who tried to show that remained unheeded.

As regards the Rorschach test, one (decisive?) difference may be that those inkblots are not made up of bits of colour on bits of paper overlaying one another, being frayed at the edges, and moving. A Rorschach test on the basis of tail patterns of eagles thus could be somewhat more challenging than the original.

[ame]

i made another picture of the tails of Milda and Raimis. let me explain what i look at in a tail. i think it can be done more understandable with the aid of a picture.
i look at two main "fields" in a tail, the centre spots (marked with number 1 and a red square) and the borderline between the dark back and the white tail (number 2 in a green ellipse).
1. the spots have different sizes and "constellations".
- Sulev's tail was like a complicated star system like the picture in the previous page shows. i think that he had many spots in the tips of many different feathers so the "stars" in his constellations looked slightly different in every picture. Linda's spots were big and looked like hearts. she had four of them in a square formation. that was easily discerned from the tail of Sulev.
2. the borderline sometimes is smooth like in Milda's tail. that is almost unique in this respect. big round-tipped dark feathers line the white tail.
most eagles, however, have a more or less broken borderline like Raimis had. there are dark "rays" sticking out in the white area. these rays form different patterns depending on their width, length and relative positions. it is a bit like the keyboard of a piano which has black and white keys with different distances between each other. one must try read the "code" which is written in the rays. Raimis had rather wide and long rays with rather wide separations.


Mr L's (Limpy's or the present male's) tail is some sort of hybrid of the tails of Milda and Raimis. he has small spots like Milda but different shape (they look like crescents lying on their back; area 1). in area 2 he has rays like Raimis, but they are thinner and shorter, but he also has some big almost round-tipped feathers on the border like Milda.
(i'm not quite sure if Nordri's picture is Mr L. the spots are too round for Mr L. )

[pazi]

It seems to me that everyone who has lungs yawns.

It's considered vertebrate trait, so yes, pretty much all animals with lungs at least. For some it is less obvious, for some birds they even seem to have the same contagious yawning behaviour that is strong in humans and apes.

[Sonchik]

I found your idea of Mr Golden Eye coming out of a situation of interrupted family life in connection with his voice and black spot (as remains of a disease he'd got over) not without plausibility. But I would not be sure that one needs to draw the conclusion that only such a background would have let him act the way he did. It may also have been just previous experience (but not of this year), or even - it is really hard to say - strong instincts. One would have to go through the time of his presence here again to mark the points that would suggest the one or the other conclusion.

Sometimes hormones are produced in stages, that is, in the order of the queue. Like the chain described by Maris: nest building - mating-egg laying - incubation.Without the first stage, the fifth stage will not turn on. They are dependent on each other. In this case, a lone eagle simply can not have hormones that provoke incubation. We need to delve into the literature to find out how this is actually the case.

Could it not just be the same thing that kept Raimis here when he conquered the territory? He came in early 2017 (and had been seen previously, too), if I remember right, tried out partnership with several females (there was no long standing resident female then as is here now) until Milda came. Again the two of them then stayed on until finally in 2018 there was a clutch. That seems to me quite an expectable behaviour - you wrote yourself quite convincingly that the eagle "bonds" with the territory which is after all the basis of his chances to procreate. So that's what I at least would be happy to accept as Mr Silver's motive for staying here now: Establish his ownership of it, so that he can then have a nest full of eaglets next year?

Quite possibly. We have a chance to find out the answer to this question. We'll see.

[ame]

i made a pair of pictures of the tails of Mr C (chips) and Mr L (Limpy).
they were taken one day apart but in similar light conditions. (the left panel with Mr C has some nostalgia: it is the last picture of Chips when he flew away for the last time.)
i have marked the main differences.
1. in the ellipses the spots. Mr C had larger spots than Mr L. there was also a "bridge" connecting the right spots to the borderline (marked with the blue line). along with the size difference of the spots this is the main difference in their tail. the bridge is visible in almost every picture of Mr C.
2. the borderline of Mr C's tail is more blurred than the border line of Mr L. Mr L's borderline is more even with some narrow and long dark "spikes" (marked with yellow lines) reaching far in the white region. these spikes are visible in most of the pictures in his tail.


Mr L's tail looks much different when the feathers are folded together. this happens with every eagle's tail and therefore it is important to have many pictures of the tails of known eagles in different positions.
i have marked the notable details here.
1. the spots look like crescents lying on their backs (marked with red dots). Milda has two round small spots when her tail is folded.
2. the border line feathers seem to have round smooth edges like in Milda's tail (marked with yellow lines). this is the characteristic which reminds of Milda. in the centre (unmarked) there is one long dark wedgelike spike with the blunt end sticking out to the middle of the crescent spots ("nose above closed eyes" in an inkblot picture ).
on the left side there is one long dark spike sticking in the white area (marked with a blue line). Milda doesn't have this.

[Ajeta]

What a beautiful picture, balistar! At first I was totally confused - it looked so much like autumn (to me at least)

[Ajeta]

(i'm not quite sure if Nordri's picture is Mr L. the spots are too round for Mr L. )

Who said so?

On the contrary: I said (and not the first time) that the picture by Nordri shows the tail of Mr X, present at the nest up to April 2nd (possibly 4th).

The other picture in my post above (by Ame) shows a stranger visiting the nest on April 7th, and it indicates two things:
1 - a marked difference to Mr X's tail depicted in Nordri's picture (as you just wrote)
2 - a strong likeness to Mr L's tail, which is not surprising as that stranger of April 7th with high probabilty (judging by tail marks as well as other features) was Mr L, who has been here from at least April 6th onwards, as Sonchik and I have tried to show here.

Despite the marked difference to Mr X's tail, which you rightly mention, poor Mr L was taken to be Mr X in the reporting of the o-thread on account of his tail patterns until April 8th when he was driven away by Mr C. This confusion is a good example for why some people mistrust the sole focus on tail patterns despite being able to read them.

[Ajeta]

Sometimes hormones are produced in stages, that is, in the order of the queue. Like the chain described by Maris: nest building - mating-egg laying - incubation.Without the first stage, the fifth stage will not turn on. They are dependent on each other. In this case, a lone eagle simply can not have hormones that provoke incubation. We need to delve into the literature to find out how this is actually the case.

But that would mean that Mr C must have come here within only a few days of whatever happened to the nest and eggs you assume he had before. Bc a hormonal state doesn't last forever when the chain or the reason for it is interrupted, or does it? (Well, it does with cats, I think, who remain prepared to mate until they actually mate, unlike dogs for example who have certain periods in which to mate and others in which not.)
Or do you think for example Milda is still in the hormonal state she was in during incubation and up to the death of her chicks?
That is one of the reasons why I am not absolutely sure whether hormonal states cannot also be influenced by outside factors.
But that, as you say, requires a lot more background reading. Yet it is interesting to ask these things. After all, one often doesn't understand the answer if one didn't ask the question first.

[Ajeta]

It's considered vertebrate trait, so yes, pretty much all animals with lungs at least. For some it is less obvious, for some birds they even seem to have the same contagious yawning behaviour that is strong in humans and apes.

You know a lot! Actually I only found out about that recently when we were discussing the difference between yawing and crop drop in eagles here. One study that seems to show this contagiousness in birds I posted here, in case you are interested:
https://www.looduskalender.ee/forum/vie ... 61#p795961

[ame]

Ajeta, i tried to say that Mr L was not in Nordri's picture. i didn't write anything about who it was supposed to be.

i haven't really started the analysis of the tails so i really didn't know whose tail was in Nordri's picture. i'm not nearly as far as that. my aim at this point was to show the differences in the tails of Mr C and Mr L.
i still have the events of the end of March unanalysed. i'll return to my findings later when i've finished.

[Sonchik]

You will probably have seen this yourself, but this is an opportunity to post my very first picture ever: Yesterday at 19:47:25 when he flew in, you could see missing feathers in Mr X2's left wing that may match the ones missing in the video in this post by you:
https://www.looduskalender.ee/forum/vie ... 09#p796109

Here my picture:


(As this is the first picture I post, I may have made all sorts of mistakes, although I read about resizing and so on. So perhaps it will have to disappear again - just so that nobody is surprised. )

Golden Boy and Silver Boy. Find 10 differences.

[Ajeta]

Golden Boy and Silver Boy. Find 10 differences.

[Sonchik]

a question about the tail marks

do you really not see any difference for example in these tail patterns?
...

I can answer you in your own words:

Nordri, i think that you are looking at too small details now. most of them are undetectable most of the time.

The tail in this expanded form is shown for a single moment from several hours of video. Why would I spend time studying tails if it's only 1% useful? But the camera is positioned so that the incoming eagles show their faces in 90% of cases. I feel sorry for the torment of people who wait for hours for the eagle to show its tail. Otherwise, they cannot determine who is in front of them. I also sometimes make mistakes in the first seconds. But after looking for 1 minute, I'm absolutely sure who I see. Sometimes there are good angles from the first second. With a tail, such luck is rare.

[Sonchik]

It's considered vertebrate trait, so yes, pretty much all animals with lungs at least. For some it is less obvious, for some birds they even seem to have the same contagious yawning behaviour that is strong in humans and apes.

Thank you for enlightening me!
Sometimes eagles yawn very contagiously.

[pazi]

You know a lot!

I just took some time to find out when the topic was first brought up here. Same as you I guess.
e: Actually the budgie contagious yawning article and the Decorah crop drop I too came across. But the pubmed study is new to me.

One study that seems to show this contagiousness in birds I posted here, in case you are interested:
https://www.looduskalender.ee/forum/vie ... 61#p795961

Thanks, Ajeta! I have missed that post. Will read.

[Ajeta]

Golden Boy and Silver Boy. Find 10 differences

Apropos their wide spread wings: Do I remember rightly that you once said you liked watching the eagles soar? It's not a WTE, so I posted it elsewhere, but this is a really nice video of two predators (Golden Eagle and Bearded Vulture) soaring (and there are more by the author on yt):
https://www.youtube.com/watch?v=3Z5OLAa55yY

[Sonchik]

But that would mean that Mr C must have come here within only a few days of whatever happened to the nest and eggs you assume he had before. Bc a hormonal state doesn't last forever when the chain or the reason for it is interrupted, or does it?
...

Yes, I think so. I also think that this hormonal background was the reason for his victory over the Silver Boy.

[Ajeta]

I just took some time to find out when the topic was first brought up here. Same as you I guess.

[Ajeta]

I also think that this hormonal background was the reason for his victory over the Silver Boy.

Interesting idea. So he might sort of have felt his own eggs were under threat from a stranger when he saw Mr Silver on the nest?
It sounds appealing. But how did he find this nest so quickly? Or would he have attacked just any nest to get back on eggs so to speak?
I also wouldn't underestimate his dive-bombing talent and his speed, as well as especially his extremely high manoeuvrability. Like rebelde, I could imagine that that was an advantage of his being potentially slightly smaller than Mr Silver.

[Ajeta]

13:47 Both on the nest.
Milda has a fuller crop than the stranger. So have those morning conversations Sonchik keeps reporting on already born fruit? Did he pass on his catch to her?