looduskalender.ee

This thread is for discussion of behaviors that we observe in the birds that we see on the Looduskalender webcams, and other behaviors that we might wish to learn about and discuss.

Some behaviors can be upsetting to human observers, for example, cainism in the Lesser Spotted Eagle and kronism in the White and Black Storks.

However, if we read and discuss these behaviors, and share resources, we will learn and better understand what is happening.

Recently, on the webcam for the Lesser Spotted Eagle (LSE), we saw an example of cainism.

In this species, two eggs are laid and hatch, but only one chick survives, even if there is plenty of food. The stronger (usually the older) chick instinctively subdues, intimidates, and kills the younger one. This behavior is well known and well documented in the scientific literature.

For example, this article is about the LSE in Latvia, where the species is in decline. Scientists there manage the nests and often remove the younger chick ("Abel") in order to help it survive.

LSE forum discussion:
viewtopic.php?f=25&t=106

Article about nest management in Latvia (also cited in yarko's post, below):
http://www.raptor-research.de/pdfs/a_sp ... ainism.pdf

originally posted 3 June 2009
viewtopic.php?p=40028#p40028

I searched a web today and found out about C a i n i s m - Cain and Abel syndrome - the killing of a nesting bird by a nestmate, always the first and oldest bird. It is most dramatic in eagles, especially Aquila.
http://dml.cmnh.org/1998Jun/msg00013.html

Here is a bit more about Cainism w i t h i n t h e L e s s e r S p o t t e d E a g l e s p e c i e - seems like reliable source of information- scroll a bit down to see the Introduction -
http://www.raptor-research.de/pdfs/a_sp ... ainism.pdf

Of course it doesn’t happen every nest - but it’s likely, and evidently Nature has it’s own reasons for that.

originally posted 6 June 2009
viewtopic.php?p=40413#p40413


Good question caysa!
i 'asked' that from Google; found this:

/.../ The existence of Cainism could be explained by the LSE´s being today at an intermediate stage in its evolution, of transition from two-egg to one-egg clutches./.../
it's here:
http://www.raptor-research.de/summary/a ... rp702.html

It would be interesting to know what Kotkaklubi's men have to say about that.

originally posted 10 June 2009
viewtopic.php?p=40998#p40998


i found some scientific research on that specific subject.
PS!!those who don't like to read about this unfortunate event, be warned... this paper gives a pretty detailed description of Cainism in the nest they studied!!!

Meyburg, B.-U. 2002. On Cainism in the Lesser Spotted Eagle (Aquila pomarina) and a possible Explanation for the Phenomenon in this and other Eagle Species:
http://www.raptor-research.de/pdfs/a_rp700p/a_rp705.pdf

Main Page:
http://www.raptor-research.de/main.html

it basically suggests that it's evolutionarily interediate stage from two-egg clutch to one-egg, (Lesser Evolved Eagle <--ok that's me being all narrow again )
But i am still searching the answer to the question why this "stage" occurs only/mainly in Lesser Spotted eagles nest..

originally posted 6 June 2009
viewtopic.php?f=25&t=106&start=1075



Yes ornithologists do that, when there is possible extinction in question.
As Urmas said, LSE species isn't under such threat in Estonia.
----------------------------------------------
I 'googled' about saving both (all) eaglets and found this:
http://simonthomsett.wildlifedirect.org/tag/eagle/
scroll down till 'Goodbye Vero's':
"/.../ Most eagles lay two eggs, 3-9 days apart. They hatch asynchronously with one being very much more robust than the other. The larger individual will almost invariably kill the younger sibling. The younger sibling has a miniscule chance and that is to kill its old sibling. Only one chick survives. /.../

/.../ If you take one chick away immediately at the hatch of the second chick, you can raise it in captivity, and produce twice as many as otherwise would be the case. But the hand-raised chick you kept would be a human imprint. /.../

/.../ When it comes to Abel rescue, I developed a technique that made sense but was physically demanding. Raise the chick in captivity for 10 days, take it back to its parents, swap it with the “wild” sibling. Take the “wild” one back. Raise that for 10 days. Take that back. ETC. Do this until they are 8 weeks old when they are large and nearly ready to fledge. Put them together and although they fight, they are equal combatants./.../ "

originally posted 7 June 2009
viewtopic.php?f=25&t=106&start=1200

Poor little spot. For some reason or another there isn't almost any chance for those younger ones - and that isn't just about Lesser Spotted Eagles.

Googled: /.../ The phenomenon of Cainism (also called siblicide > siblicidal birds) is known to occur in at least 27 of the world's eagle species
- and number of other larger birds like Great Egrets (Casmerodius albus); Great Blue Herons (Ardea herodias); Blue—footed Boobies (Sula nebouxii), Black—legged Kittiwakes (Rissa tridactyla), Ospreys (Pandion haliaetus), South Polar Skuas (Catharacta maccormicki) etc./…/

/.../ The actions of any animal species, even if they seem cruel to us, are generally those behaviors with the highest probability of passing the parents' genes on to the next generation. /.../

originally posted 7 June 2009
viewtopic.php?f=25&t=106&start=1200

Found article about Sibling Aggression and Siblicidal Tendencies in Birds

There are several hypothesis about such behaviour:
- food amount hypothesis
- prey size hypothesis
- brood size hypothesis
- challenge hypothesis;
- also about The Role of Parents in Siblicidal Aggression.

it's here: http://209.85.129.132/search?q=cache:9A ... clnk&gl=ee

originally posted 8 June 2009
viewtopic.php?f=25&t=106&start=1250

There is an interesting study about LSE sex ratio
Ülo Väli - Sex ratio of Lesser Spotted Eagle Aquila pomarina nestlings in good and poor breeding years.
http://www.zbi.ee/~yvali/artiklid/BS2004.pdf

and there are more publications from the same (and other) authors, incl Urmas!
Lots of information about Spotted Eagles:
http://www.zbi.ee/~yvali/personal/publications.htm

originally posted 10 June 2009
viewtopic.php?f=25&t=106&start=1325

i asked our eagle specialist Tiit Randla's comment about Spot#2.

Tiit replied -
"White tailed eagles raise only one chick in almost all nests.
That kind of nesting stratey of this particular species has justified itself for ages already.
Better one viable successor than two weak ones.
It is biologically locical - though strange from human's wiewpoint."

Originally posted 13. June
viewtopic.php?f=25&t=106&p=41285#p41285

Found something about hybridisation of LSEs and GSEs:

/.../ Hybridisation between spotted eagles has a particular importance since both species are threatened and a regular interspecific hybridisation is unusual in raptors./.../

/.../ Hybridisation occurs regularly in spotted eagles and a large proportion of the Greater Spotted Eagles in the sympatry area are interbreeding. Hence, the hybridisation has an obviously negative impact on the Greater Spotted Eagle even in the case of limited fertility of hybrids and a lack of introgression.

The possible reasons for the hybridisation include rarity of the Greater Spotted Eagle and competition for mates and territories in the Lesser Spotted Eagle. Hybridisation is strongly asymmetrical, and since larger females are more successful breeders, the Lesser Spotted Eagle males could prefer to mate with the Greater Spotted Eagle females.

Despite their similar behaviour and regular hybridisation, spotted eagles should be treated as a separate species. According to the superspecies concept, the semispecies status seems to be most appropriate./.../
http://209.85.129.132/search?q=cache:CH ... clnk&gl=ee

Hello to you all,
I've returned from my three weeks holiday in Mecklenburg-Vorpommern, home of Lesser Spotted Eagle (Aquila pomerania). Sorry to say that we only twice had the opportunity to see the bird. Once on a tree at the edge of a near by wood, where it sat for a long time in about 70 m distance. And once a pair souring through the sky. But we saw a lot of other rare birds . . . but that's o T

Back to the topic of the thread: at first thanks for opening it, because I thought about that interesting topic while reading the forums last three weeks posts.

Especially I studied those videos with the tragedy of Spot's little sibling. It seemed to me that there was a lot of imitation of mothers behaviour in Spot's action besides the not unusual sibling's trial to get most of the prey mother served: get down, stay down, don't come between me and mother's feeding beak.
And in the last video Spot made similar movement like Eha did: she stood upon the prey and threw parts out of it with her beak; it stood (pardon, sat) upon his sibling and tried to pluck the small wing of it's sibling. You may recognize imitiation behaviour as well while preening, looking for potentiall agressors and so on.
Maybe there are several instincts together responsible for cainism: agression specially because of eagerness for food and demand of exclusiveness as well as imitation of mothers behaviour especially while feeding. I mean: an egoistic genetic behaviour for the survival of the fittist.
The second sibling may therefore only survive when it's not much smaller than the older one and able to fight for it's life.
May be Tiit or Urmas are able to tell us more.

hello, Leonia, welcome home!

You have made a very interesting observation about the young imitating the parent. This species is very intriguing.

For several years now we have had sparrow hawks breeding in the garden park behind our office. The office is situated in the middle of a part of Munich called Schwabing. It's a part quite near to the centre of the town and is totaly covered with houses. Besides the public "Englischer Garten" on the side of the river Isar, there are not too much larger garden parks in the area. Although the sparrow hawks have had fledgelings every time they breeded, last year they had three. This year they occupated the nest of a pair of crows and have four young ones.
Friday two weeks ago a collegue of mine who has an excelent place for looking at the nest sat at her desk when suddenly the possibly youngest of the young ones flew to her window and sat down outside. She called a collegue who had a camera there and he made some pictures, one of them I borrowed for my avatar.
To add, the house we are working for has a more than two hundred years old sign: a griffon. We should change it to a sparrow hawk

This is the abstract of an article about female Lesser Spotted Eagles visiting other nests.
http://www.springerlink.com/content/j7t872u1186w1nl6/

Would we know if an other female visited Spot?

Maybe this should be posted elsewhere but...

http://seedmagazine.com/portfolio/16_fl ... terns.html

There are 4 images of many birds in flight. No information but ... a question of how birds and fishes move about in unison the way they do.

That is a very interesting site. Thanks, Alice.
It is interesting to know that the formations of groups is being studied.
Yes, how DOES a wound send out signals to gather all the various cells needed for healing?

Today I saw a funny scene: a lot of pigeons were peacefully pecking a slice of bread together. A crow appeared, took that slice away(none of the pigeons reacted), threw it in a puddle, waited for some time and then began to eat bread right from the puddle.

Alice,I saw a documentary film on that very question last night on t.v. (The BBC,of course ) I then spent hours looking for it on the net. No luck and thats a great pity as ALL WAS EXPLAINED..!
Now,if anyone happens to find it.....please share.
Tonights report showed how sophisticated the world of ants is and how they communicate and organise themselves. A wonder to see. (from a German T.V. study.) Don't even hope to find that.
BTW if this shows up in (very bad) French..!! Don't blame me. Blame Google who have decided unilatterlly to translate EVERYTHING I write or read.

I fixad THAT!! (with a little help) Google can do strange things to your posts,if you are not careful.
Sorry off subject..