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SUCCESSIVE BREEDING SEASONS
Karl I (715R) and Kati
2016
The nest was found in February 2016. Two adult Black Storks arrived at the nest on April 5. They were named Karl and Kati. They had no rings and no transmitter.
There were 4 eggs. Three hatched. One of the 3 chicks had a severe growth retardation and did not develop normally. That chick clearly had a health problem and has been eliminated by Kati. The other 2 storklets (
Kulla and
Kalli) were well fed and fledged successfully.
On July 15, Karl was trapped on foraging grounds (a little brook) about 1.5 km from the nest site and received rings and a transmitter. After being captured, he did not visit the nest for two days, but then he resumed his normal behaviour.
2017
Karl I and Kati reappeared on the nest. Their joy at being reunited was very moving to see.
There were 4 chicks. Although the youngest chick looked healthy, it was eliminated by Kati.
The reason why bird infanticide (brood reduction) occurs on a nest is well described here:
viewtopic.php?p=686634#p686634
The remaining 3 storklets (
Unu,
Tali and
Usin) were well-nourished and fledged successfully. They had no transmitter.
The old nest collapsed after the 2017 breeding season.
A new - artificial - nest was build by Urmas & Friends in the same tree, before the 2018 breeding season began.
2018
Once again Karl I and Kati were present in the spring.
This couple was very harmonious and had a wonderful relationship.
There were 4 eggs, but only 3 hatched. All 3 storklets were healthy and well-fed. All 3 fledged successfully. Unfortunately
Päike and
Maru perished during their first autumn migration. Our beloved
Karula perished in Turkey, shortly before his 3rd birthday.
Kati, Karl I and their 3 chicks on 3 June 2016
Photo: Liz01; viewtopic.php?p=473080#p473080
Karl II (716C) and Kati
2019
Karl the First unfortunately perished on his way home in spring 2019, on the Lebanon-Syria border.
Karl II took ownership of the nest.
Kati, who for several years had been the mate of Karl I, arrived at the nest and accepted this new male. Kati laid four eggs. All 4 chicks hatched.
From the very beginning, nest watchers were impressed by Karl II, a tireless stork, a diligent nest builder, a talented hunter, and an exceptionally caring father. He made sure the chicks were not short of anything and repeatedly moved us by his visible concern to cleverly ensure that even the youngest chick had a fair chance to grab enough food. Karl II had stolen our hearts!
Still, Kati eliminated the youngest chick. Brood reduction is not uncommon in Black Storks when a parent considers that there will not be enough food to raise all the chicks. Another chick was knocked out of the nest by a goshawk during fierce attacks. The 2 remaining juveniles,
Oru and
Aru, fledged successfully but unfortunately perished during their first autumn migration.
Kati and her 4 chicks at sunrise, 23 May 2019
Photo: Anne7; viewtopic.php?p=658548#p658548
Karl II (716C) and Kaia (718U)
2020
In the spring of 2020, Kati did not return from migration for unknown reasons. Presumably, she also perished. Or — who knows? — perhaps she didn't like Karl II as much as her first Karl, with whom she had built a strong bond, and decided to stay away. It is known that there is an increasing shortage of females in Estonia. This is problematic for the Estonian Black Stork population. The reason for this phenomenon has not yet been fully elucidated. Could it be that it is the females who, at some point, decide not to return to Estonia and seek their fortune elsewhere? Maybe somewhere not so far away from their wintering grounds and in places where more food can be found?
At the beginning of May, a very young and rather small but graceful female appeared on the nest. She was named Kaia by the forum members. Kaia laid two late eggs but stopped incubating a few weeks before the eggs were due to hatch. Karl II sat on the eggs continuously for three days and nights, hoping Kaia would still come home and take over brooding for a while. She didn't. Kaia was in poor condition at the time. She was shy, skinny, and visibly suffering from external parasites. Presumably, she was also too young to take on motherhood.
Since the eggs were lost, Kotkaklubi members had the opportunity to trap Karl II and to provide him with a transmitter and rings (white ring 716C), without the risk of disturbing nest life.
Thanks to that transmitter, we learned that Karl II was in the habit of taking a very long break in Ukraine during his autumn migrations, on the Black Sea coast between Kherson and the Crimean peninsula. Wintering took place in Africa, first for a few weeks in South Sudan and the rest of the winter in the Central African Republic, on the border with the Democratic Republic of the Congo.
2021
In spring 2021, the joy was great when Kaia returned to the nest in Karula National Park. She now looked much better, had grown up, and seemed healthy. Karl II was clearly smitten with her and did his utmost to please his beautiful Princess. The nest was overloaded with branches and twigs, and huge loads of moss.
There were 4 eggs. One of the eggs broke during incubation. Three chicks,
Udu,
Pikne and
Tuul, hatched and fledged successfully. Little Tuul was predated shortly after starting his first migration. The two others flew to Africa. There they spent their first winter successfully. Pikne perished in Turkey in 2022, most likely because of a collision with high-voltage power lines. Udu flew to northern Italy in 2022, stayed there until late autumn, and spent his second winter in Turkey, near the archaeological site of Troy. Unfortunately, there is no further information on Udu, as the transmitter used is not well-designed to track black storks.
Kaia turned out to be a lady with spunk and a strong character. She knows what she wants, is very sensitive and smart, and communicates exuberantly. She is very caring about her eggs and chicks, and protects them with great courage. Despite her delicate, elegant appearance, she grabs intruders by the neck and resolutely flings them out of the nest. She often "talks" to Karl II. Kaia expects Karl II to understand and carry out her wishes and does not hesitate to also toss him out of the nest if he does not.
Occasionally, Kaia's temperament led to "marital scenes" that we did not observe on other Black Stork nests. Observers were puzzled by Kaia’s behaviour, and opinions sometimes diverged. Some thought she was hysterical. Others understood that Kaia is simply different from other female Black Storks. Maybe she is smarter, and certainly she is more communicative.
Urmas Sellis, biologist, ornithologist and Black Stork expert, wrote on the forum:
“Crooked or strange behaviours (mutations) occur during evolution. Most of these mutations are negative for the species, but some are beneficial. Matriarchy and emancipation may be something like that, in case of a shortage of females in the black stork population. To save the species. Someone may be able to analyse in thousands of years, whether that is really happening.
On April 30, it looked as if a visitor was sitting on the branch above the camera. Kaia was angry with that stranger, but Karl II only shouted at the intruder, from the nest. Perhaps Kaia did not like such behaviour, and perhaps that is why she assaulted Karl II. In the same way, she previously attacked a strange stork that tried to enter the nest from a branch slightly lower than the nest.
The other day the situation was similar, a strange stork sat on a branch nearby. Karl II scolded him, from the nest. Maybe Kaia couldn't bear those strong words — instead of actions! —, or maybe she understood the swearing as directed at her? The latter seems even more plausible to me: defensive behaviour might be interpreted as aimed at females. And accordingly, countermeasures are needed to take action against the swearer. Maybe I'm wrong, but that's how it seems to me.”
An observer assumed that Kaia simply did not want Karl II to be on the nest when an intruder is around, as a fight on the nest would be too dangerous.
"Go after him, Karl! Go fight elsewhere!" Black Storks sometimes engage in fierce fights, and when such fights take place on the nest, they are extremely hazardous to eggs and chicks.
2022
In 2022, both Karl II and Kaia were back on the nest in spring. Again, their joy of reunion was overwhelming.
Both Karl II and Kaia worked very hard, as usual. Over time, their relationship had become more harmonious and they seemed to understand each other very well. Three beautiful chicks (
Waba,
Voog, and
Iks) hatched and all three grew up well. An orphaned chick, named
Bonus, was put on the nest. That experiment — an attempt to rescue the chick — was successful. The foster child was accepted and fed by both Karl II and Kaia. At two locations ("fish restaurants”), the adult birds were fed additionally to improve the body condition of all four chicks before they started their first migration. Supplementary feeding can make the difference between well-fed and malnourished fledglings. Being well-fed is very important for their migration success. Two chicks (Waba and Bonus) received a transmitter. They both flew to Africa and survived their first winter and next summer well.
Just before autumn migration, Kaia was also trapped and fitted with rings and a transmitter (white ring with black code 718U).
As usual, Karl II was the last to leave the nest, and he flew straight to the Kherson Oblast in Ukraine. In the meantime, a war was raging there, which ment no transmitter data was getting through. We had to wait, anxiously. Will Karl II appear unscathed on the radar?
Video of Kaia at the fish restaurant, before she received a transmitter
https://www.youtube.com/watch?v=WvRzMGH ... Kotkaklubi
2023
2023 was a bit of a strange season.
Kaia arrived at the nest a bit later than usual. Meanwhile, Karl II had a brief “liaison” with an unknown female. We feared a fierce fight between the two females, but Kaia’s rival disappeared from the scene as quickly as she had come.
For several consecutive years, it had been too dry and too hot in Estonia. Global warming and climate change are taking their toll. Ditches, streams, wetlands and ponds were drying out. Estonian Black Storks found fewer and fewer fish and frogs. Some nests were abandoned and chicks starved to death.
Kaia laid four eggs. All four eggs hatched.
The youngest chick lagged behind in growth. Kaia observed the little one closely, and it became clear that she was considering brood reduction. Didn't she have the heart to complete that difficult task herself? Attentive observers reported that Kaia seemed to instruct Karl II to eliminate their youngest chick. That proved to be a correct observation. On June 15, at 19:39, Karl II removed chick number 4 from the nest. It is believed, but not seen, that he dropped the chick in the forest.
Thanks to the tremendous effort of Kotkaklubi members and volunteers, the "fish restaurants" were running at full capacity. Not only this nest in Karula National Park, but almost every known Black Stork nest was provided with supplementary fish. People emptied their private ponds, or caught fish in larger lakes and rivers, to help the Black Stork population. Mainly an invasive and therefore harmful fish species was served: Prussian carp (Carassius gibelio). Prussian carps are highly invasive in areas outside their native range. They reproduce and spread rapidly. Karl II made grateful use of the fish baskets placed in nearby brooks. The 3 chicks,
Kalvi,
Kerri and
Kiire grew very well. Kalvi received a transmitter.
Kaia has also been spotted a few times at the "fish restaurants", by trail cams. But we did not see her taking the fish from the baskets to her chicks. She stubbornly kept trying to find self-caught, natural food for her chicks. She appeared at the nest less and less often.
She eventually stopped bringing food to the nest on July 23. That was much earlier than in previous years.
Of course, we don't know what exactly was going on in Kaia's head. Presumably she realised that her chicks were doing very well and had grown bigger and heavier than their mother. Maybe she concluded that her help was no longer necessary. Obviously, in these times of food scarcity, she also had to think of herself. She had to try to survive and build up sufficient fat reserves to successfully start her own autumn migration.
However, Kaia remained in the (wide) vicinity of the nest. Thanks to her transmitter, we know that she occasionally came to look at her offspring, but without landing on the nest, without offering food.
Since both parents now had transmitters, we also know that Karl II apparently knew very well where Kaia was looking for food and that he visited her. Was there some form of communication? And if so, what did they "tell" each other?
On August 22 Kaia started her autumn migration and flew to Ukraine.
The 3 strong and well-fed juveniles left the nest together on August 30.
After making sure that the chicks did not return and after regaining some strength, Karl II started his autumn migration on September 3 and flew straight to the Kherson Oblast in Ukraine. Because of the war in that region, his transmitter was again silent for weeks, and again we anxiously awaited the first sign of life.
Karl II and Kaia on 3 June 2023
Photo: Swenja; viewtopic.php?p=902519#p902519
A truly great article, written with warmth and compassion. Many thanks.
. Knowing that there are so many people who care about them gives me hope for the future and a reason to believe that the loss of the amazing Karl II, and many others, was not in vain 
.
