Discussion about ringing + fitting birds with transmitters

[oksi]

Liz, thank you very much for the reply! So I see not always, but often (if we take the cases of 2012) ringing brings sorrow. Perhaps this is true that parents saw ringing. So I wonder do ornithologists analyzethese mistakes not to repeat them... Because the price is too high. Until they never speak about it. Only about the importance of ringing...

Maybe near the pond, really, a lot of people because of the holidays? But we don't hear any noise.

[Summi]

I have been watching the cams since BS Tooni & Donna nest in 2007 - mostly as a silent watcher - and it seems that WTE-s and LSE-s are most sensitive to ringing disturbance, for instance buzzards returned in less than an hour and when the nest is not in an open area, the parents return usually faster. Of course there are exceptions. But don't you think that in the present case the fact that the nest has been built only this year and has not been used for nesting before meaning that the ties between WTE's and the nest as "our old home" from earlier are missing and therefore the human intervening more severe and destructive.

[oksi]

I have been watching the cams since BS Tooni & Donna nest in 2007 - mostly as a silent watcher - and it seems that WTE-s and LSE-s are most sensitive to ringing disturbance, for instance buzzards returned in less than an hour and when the nest is not in an open area, the parents return usually faster. Of course there are exceptions. But don't you think that in the present case the fact that the nest has been built only this year and has not been used for nesting before meaning that the ties between WTE's and the nest as "our old home" from earlier are missing and therefore the human intervening more severe and destructive.

Maybe that was the reason too! I wish the experts also spoke on this subject, not only we, dilettantes. This would act more carefully in the future. I think people don't need to calm down, they need to know that scientists are thinking about it.

[Hagnat]

Oksi, I don't think it is a sign of good judgement to call everybody who contributed to this discussion a dilettante.

[oksi]

Oksi, I don't think it is a sign of good judgement to call everybody who contributed to this discussion a dilettante.

This does not mean that we can't discuss what we see. You against the discussion?

[ame]

... I wish the experts also spoke on this subject, not only we, dilettantes. This would act more carefully in the future. I think people don't need to calm down, they need to know that scientists are thinking about it.

i think that scientists have thought and spoken about this subject for decades already: ringing started about 100 years ago. we also know what they thought and still think: that marking birds with rings or wing tags or satellite trackers is a useful and a very important method in ornithology. i'm sure that they also practice utmost care in marking birds: they love birds and certainly not wish to hurt them.

the points of view of scientists can be read in various places. it takes just little effort to look them up. as an example of where you can read about the scientific grounds and reasoning of bird marking i took the one that is closest to me: the web pages of the Finnish Museum of Natural History:
http://www.luomus.fi/en/bird-ringing#Mi ... ngastetaan

i'm sure that you will find similar information on the web pages of every similar scientific institution in any country (scientific or natural history museums). we can't expect scientist to find this forum and take the trouble of convincing each dilettante separately. - and yet Urmas has done so! thank you Urmas!

- and finally: i think that us dilettantes really need to take a calm attitude towards this question when we are discussing this subject. reasoning and rational discussion becomes impossible if we let ourselves be carried away by emotions.

[Hagnat]

The points of view of scientists can be read in various places. It takes just little effort to look them up. As an example of where you can read about the scientific grounds and reasoning of bird marking I took the one that is closest to me: the web pages of the Finnish Museum of Natural History:
http://www.luomus.fi/en/bird-ringing#Mi ... ngastetaan
I'm sure that you will find similar information on the web pages of every similar scientific institution in any country (scientific or natural history museums). ....

A good example is the page 'Bird Ringing for Science and Conservation' on the site of Euring. http://www.euring.org/about_euring/broc ... index.html . Available in several languages. Also as pdf.

Btw. This dilettante has ringed thousands of birds.

[ame]

... Btw. This dilettante has ringed thousands of birds.

so you have your own cow in this ditch!
(this is a Finnish saying which says that someones is personally involved with the thing under discussion.)

it's great to have a pro here.
now we can ask also you to identify birds. so far vainamoinen has been about the only reliable identifier whom we have been able to ask for help. he is often busy and haven't seen our requests every time we have needed help.

[Hagnat]

Everybody in this discussion has a cow in the ditch, but not everybody in the same ditch and some even have cows in several ditches. It doesn't matter to me who has a cow in which ditch, as long as there is a rational discussion possible based on facts.

[Janne+Ais]

A good example is the page 'Bird Ringing for Science and Conservation' on the site of Euring. http://www.euring.org/about_euring/broc ... index.html . Available in several languages.

Very interesting!!! Thank you very much for this link!

[asteria]

thank you asteria for this contribution!

did you survey all the nest topics for this summary or only these that you remembered or are quite recent?

Nope, I only reminded of some facts when ringing or tagging hurt the birds and also a few facts when nothing bad had happened. I remembered about them without opening the threads.

[ame]

thank you asteria for this contribution!

did you survey all the nest topics for this summary or only these that you remembered or are quite recent?

Nope, I only reminded of some facts when ringing or tagging hurt the birds and also a few facts when nothing bad had happened. I remembered about them without opening the threads.

ok, so you survey was not systematic nor comprehensive.

[asteria]

Of course not, it were only some random examples and that is all. Moreover, the case with Durberts is even "not finished", because it will be important to see the behavior of parents couple next year. Will they stay here or change the nest?

[Hagnat]

I think it would be very difficult (almost impossible) to find a relation between a particular kind of event in one nesting season and the not returning in the next, especially when there are many events and circumstances to consider, like in this case the robbery of eggs. You need many cases with ringing and without ringing as well to compare abandon rates.

[ame]

i looked up the statistics of ringed Finnish WTEaglets. the numbers are from the WWF Finland's Sea Eagle Working group.


the ringing was started in 1970 and in the first years only few eaglets hatched. 1975 was the worst year: only 4 eaglets. the Finnish population was on the verge of extinction. this was mostly due to persecution and environmental poisons (mercury compounds, DDT, chlorinated hydro-carbons etc) enriching in the bodies of eagles who were on the top of the food chain. the eggshells were so thin that the eggs just broke before hatching or the eggs were infertile to begin with. the poisons effected all birds of prey in a similar way. that was really bad time for them. also decades long persecution had weakened the population even before the invent of these poisons.

i haven't seen statistics but i believe that most of Finnish eagles' nest were known but as one can see very few eaglets were raised in these nests. i'm sure that the nests were checked every year in hope of finding eaglets.

in the 1980's a turn for the better can be seen. this was due to at least two factors. the use of the environmental poisons was banned and the food chain began to clean up. the winter feeding of eagles was begun: tons of pigs were dragged out in the wilderness both on the mainland and on islands to give eagles an opportunity to have an ample supply of clean food in the winter time. - also the persecution by humans was slowly becoming rarer, though it still continues to some extent.

from about 1995 a steady increase of numbers of ringed eaglets can be seen in the graph. this strengthened population must include a large amount of ringed eagles as parents as well. this growing population must also mean that there are new nests in new territories. some of them must be undiscovered still but as they are then ornithologists have started to check them, too, on yearly basis and the eaglets have been ringed.

i think we can conclude based on this data that the ringing of eaglets has definitely not had any significant negative effect on the development of the WTE population in Finland.
(i don't think that anyone would claim the opposite either: that ringing would have increased the population. )

i don't believe that nests have been abandoned more often than normally (without humans visiting the nests for ringing). known nests are visited every year and still they have remained mostly occupied. i would guess that perhaps about 70 - 80 % of nests are probably known. due to the increasing population and the need for new territories there probably are new nests which may still be undiscovered at present.

in the above i wrote "mostly occupied". this is due to the fact that a WTE couple normally has several nests in their territory. they use one of them and the others are in reserve. after a few years they move from one nest to another. this is quite normal and it has been known to happen for a long time. nobody knows the reason for this behaviour though. i once guessed that this may happen due to sanitary reasons: the nest and its surroundings become contaminated by food excrements and faeces and therefore is healthy to leave it to clean over a few years.

so if Durbe and Ronert would choose another nest next year it is not certain at all the that it is because they have developed an aversion towards the present nest because it was visited by a human. it might happen anyway. we cannot know.

[Hagnat]

i looked up the statistics of ringed Finnish WTEaglets

Unless there was a major increase in ringing-effort, this shows us that ringing did not stop the eagles increasing.
I suppose year to year fluctuations reflect variation in productivity and not the number of nests.

[ame]

i think that the ringing effort remained the same. the known nest were checked and the broken eggshells were collected for research. i think that the numbers reflect real increase of the population.

(i was starting to write my post above when the dragonfly came and interrupted. i finished afterwards. that's why there is a lot of new text in the above post of mine. )

[asteria]

I think it would be very difficult (almost impossible) to find a relation between a particular kind of event in one nesting season and the not returning in the next, especially when there are many events and circumstances to consider, like in this case the robbery of eggs. You need many cases with ringing and without ringing as well to compare abandon rates.

It is very unlikely the WTE couple would leave the nest because of crow: crows are not only egg-robbers but sometimes may become a dinner. While people are considered as a real danger and there are many cases when wild birds abandon the nests because of people. Linda and Sulev didn't leave the nest and we watched two seasons but this case is really different.

[Hagnat]

Ringing people do no real harm to the brood, an egg-robbing crow does. This pair of eagles has lost half their offspring.

[asteria]

Ringing people do no real harm to the brood, an egg-robbing crow does. This pair of eagles has lost half their offspring.

Yes, but eagles can't know that people do no harm and still consider them as serious enemies.
As for the crow: the eagle couple left the eggs alone and that was the reason they lost one(maybe they didn't have enough experience). Not because crows are that dangerous for eagles(unlike WTE are for black storks).