Info by Mฤris Strazds
"1. You CANNOT determine the age of black storks by plumage, including the color of the head, beak and red legs. It is as wise as judging that, say, a person with a crooked nose is older than a person with a short and pointed nose. birds are distinguishable in appearance up to 2 years of age, but then they do not nest.
2. Technically, a bird that has reached nesting age (what are all the ones seen on the cameras) CAN nest. The youngest age at which a young M is known to have laid an egg is a full 2 years (third calendar year). No nesting M dressed as an adult bird is too young to lay an egg.
3. A fertilized egg is not enough for M to lay an egg. Most of the weight and volume of the egg is made up of nutrients, which M must "provide" in a very short time. The egg is formed within 48 hours. If there is not a sufficient amount of high-quality food available at this time, it is possible that the eggs are not formed simply because there is nothing to create them from (but it is known that birds can not nest because they "don't want to", just like people, not all of them have children ). A good indication of how good M's condition is is the length of her dung stream (and settling frequency) โ for a well-fed bird, the stream is much longer than 1m (estimation is approximate, based on photo traps and webcam pictures), i.e. taller than his own height. If everything seems fine with that, then there are probably other reasons for not nesting, which cannot be seen in the cameras."
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๐ข๐ก ๐ง๐๐ ๐ฅ๐๐ก๐๐๐ก๐ ๐ข๐ ๐๐๐๐๐ ๐ฆ๐ง๐ข๐ฅ๐๐ฆ ๐๐ก ๐ง๐๐ ๐ข๐ก๐๐๐ก๐ ๐ก๐๐ฆ๐ง
First, some comments on bird anatomy and some terms used. The rings are placed above the joint so that they are visible when the bird is feeding while paddling through the water, only the joint is not a "knee" as several commentators wrongly write it. Birds, of course, have a knee like all vertebrates, only it is in the body and not visible. The visible joint is analogous to the mammalian (including human) heel. So, rings for storks are put on the lower leg. The part of the leg that is below the joint is called the stump. So much for anatomy.
Mฤris Strazds
2024-06-20
Black storks are ringed on the ground so that it is possible to measure them, to determine their age based on measurements (in this nest the age is determined by what is seen live, but in all other nests there is no such possibility) and condition, which is the most important prerequisite for success. The number of chicks in the nest in itself does not mean anything (good) - four weak young birds that can die immediately after leaving the nest or even die in the nest is much worse than one well-fed young bird.
It is the repeated controls of the ringed birds after years that allow the actual success to be established. In this regard, a note about what could be called the "deadly sin" of trying to figure out the parts of the ring number that are not clearly visible (which at least "flooded" in the Youtube chat next to the live screen). Just one such "attempt" discredits the particular observer forever, because one who poems once can never be trusted again. Ring readings are only valid if they are 100% certain - usually if there is a photo where the ring number is clearly legible, or if the ring itself has been removed from the dead bird. If the ring as such is visible, but not readable to the end, then it must be "reported" as such. Clunky ring numbers are not something you should try to "stand out in company".
Secondly, the age of the chicks is counted from the moment when the chick is completely out of the egg until the moment of ringing "for a minute". The condition of the chicks is determined by relating the weight of the specific bird to the average weight curve of the corresponding age for those birds that have successfully grown and reached the age of at least one full year (are alive in the second half of the second calendar year). Since females are about one-tenth lighter, any weight value for females greater than 90% of this control curve is very good. For males, the weight should be 100% or more, but for small babies, it is not always possible to determine the gender by measurements alone. Also, instantaneous weight (what each bird is at the time of ringing) is greatly influenced by how recently and how much he or she has eaten. Therefore, any of these numbers is only a rough indication of the bird's current condition. These numbers are a very strong indication of the impending end if they are well below "normal", but if they are at or above normal, they say essentially nothing. The decryption text could be: Everything is fine FOR NOW.
It should only be remembered that chicks of this age should normally spend at least another 50 days in the nest (preferably more) and during this time a lot can change. Furthermore, even exceptionally good condition throughout the nesting period (if available for a bird) is absolutely no guarantee for it after leaving the nest. What a very good condition gives is a longer reserve of time to find a good feeding place and restore resources. However, if the bird is not successful when it comes to taking care of itself, then he or she may not have enough of any reserves provided by the parents.
https://dabasdati.lv/lv/article/par-mel ... es-ligzda/
Age of departure from the nest without return
Mฤris Strazds
2024-08-01
I received a message from Mฤris Stradzs regarding the age of the juveniles' departure from the nest. Average age of successful juveniles whose age is known at departure from nest (without returning there) is 85.1 days (n=15, 77.5-91.6). Only three of those 15 birds have been younger than 80 days, so likely the later juveniles leave the better. The youngest successful bird was Mare, she was 77.5 days at departure (NOT 72!)
Human disturbances & impact on the nest area when the juveniles are already able to fly
Mฤris Strazds
2024-08-04
Adults do not care humans next to nest tree or near bye while approaching nest with (large) juveniles โ most of them seem to approach nest โon autopilotโ mode. About once in 10 cases during ringing adults approach nest and feed youngs while we are under nest or even on the tree straight under the nest. A few times adult bird has almost landed on back of my colleague who is IN the nest.
All that said, it is not โinnocentโ if people frighten birds to the point when they all leave the nest and never return โ see my previous email about departure ages. Mean age of birds that leave the nest because of (human; precise cause not known in most cases) disturbance is 76,8 days (67.4-82,6, n=25). Age of this company at the time of my writing is 73,6 (F3), 73,8 (F4), 73,0 (F5) 71,7 (F6). Two of those frightened 25 are younger than the youngest of these four. An important addition to that is โ none of those 25 have appeared anywhere afterwards. Some still might (we do have the 1st records of some ringed birds be registered just 10 years after their ringing) but for now they are likely among those that have failed. So I consider significant disturbance this time of year be worse than any other time of breeding season. (Disturbance in early spring may mean there might be no breeding at all, however adults in that case are free and can โenjoy summerโ on their own, if it happens now it may mean waste of season, no success plus both adults are exhausted and may have reduced capacity to make it to the next year).
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2021 there were no chicks, in nest
Enough snow to ensure that the ground is sufficiently wet and the ditches and brooks are full water in the spring. I am delighted 
