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Knepp breeding season overview 2024The 2024 breeding season was a milestone for Knepp’s stork colony, marked by significant achievements. This overview highlights some of the key moments.
At Knepp, around 25 nonflying storks are housed in a secure, predator-proof enclosure. These storks, brought from Warsaw Zoo via Cotswold Wildlife Park in 2016, play a pivotal role in the project. They act as a magnet, attracting wild storks and forming the core of a growing colony. Staff and volunteers often refer to the area around the pen as “Stork HQ,” as it is where most wild nests are constructed. As highly social birds, storks prefer to nest near one another, and this central location has become the heart of the colony.
Despite being unable to fly, the resident storks are contributing in a remarkable way. They have successfully started breeding, producing young storks that are free to fly and migrate, even though their parents can’t guide them in these behaviors.
It wasn’t until 2023 that these “grounded” storks began to breed. In the wild, many sustained injuries from collisions with power lines or traffic in Poland, leading to permanent wing damage. However, after rehabilitation, they have adapted and are now vital contributors to Knepp’s growing stork population.
The storks took some time to adjust to their new environment, likely due to their limited mobility, which made them feel more vulnerable. However, by 2023, three nests were successfully built on the ground, marking a thrilling milestone for everyone involved in their care.
From these nests, three young storks eventually fledged. Two of them, tagged with satellite trackers (GBC6 and GBC7), allowed conservationists to monitor their progress. All three chicks fledged at the typical time, learned to fly, and migrated alongside other juveniles in their first year.
These three storks were part of a total of 26 chicks that fledged in the wild at Knepp in 2023, marking a highly successful breeding season.
At the start of 2024, the team was eager to see how the breeding season would unfold, especially after the success of the previous year. Volunteers worked over the winter to prepare the pen, which involved digging a new ditch, clearing overgrown vegetation, and coppicing willow to provide nesting material for the nonflying storks.
The early signs pointed to a promising breeding season. By mid-February, some storks had already begun repairing or building new nests, with mating activity observed as early as the start of the month. Many of the adult storks at Knepp don’t migrate, choosing instead to remain near their nests throughout the winter, allowing them to begin nest-building early in the season.
By mid-March, based on observations, the team estimated that over 20 nests contained eggs, setting the stage for another productive year.
Thanks to the dedicated efforts of volunteers who spend countless hours monitoring the stork colony, a wealth of data is collected. One critical aspect of this work is tracking when eggs are laid, which allows the team to accurately determine the ideal time for ringing each nest. Typically, juveniles are ringed when they are between 45 and 55 days old.
In early April, drone surveys began to assess the number of eggs. This delicate process depends on favorable weather conditions—no wind or rain—and relies on the incubating stork standing to turn its eggs, allowing the team to gather data. Storks usually lay up to five eggs, and the team aims to conduct two or three drone surveys per nest to record the maximum number of eggs. To avoid disturbing the storks, the drone is only flown when the female stands to turn her eggs, which typically happens about once every half hour. The drone is always kept at a safe distance. This season, over 90 eggs were counted in total.
Ground nests, naturally, were much easier to check. It was exciting to see nine ground nests built early in the season. However, the wet spring weather posed challenges. A heavy downpour in early May drenched some of the nests, and unfortunately, two recently hatched chicks did not survive after getting soaked. While stork chicks are fairly resilient, one of the biggest threats to their survival in the first week of life is getting drenched before they develop the ability to regulate their body temperature.
The survival of the ground nest chicks was greatly improved by the efforts of project staff and volunteers. Since the nonflying parents can’t forage as widely as their wild counterparts, the chicks receive a daily boost through ‘assist feeding.’ This carefully coordinated process involves a team member quickly visiting each nest to drop off pre-prepared food—typically fish or minced meat—for the young storks. To minimize stress on the adult storks, the team follows the same route at the same pace each time, allowing the adults to become familiar with the routine. With guidance and training from experts at the project’s partner, Cotswold Wildlife Park, who have extensive experience in stork breeding, the adults quickly adapted to this method.
In 2024, nine chicks successfully fledged from ground nests—three times the number compared to the previous year. These nine were part of an impressive total of 53 chicks that fledged across the site at Knepp, all leaving their nests by mid-July. Despite the challenging spring conditions, it was reassuring to witness such a successful breeding season. Several nests produced three or four chicks, a strong indicator of the colony’s health.
With the exception of the ground nests, all the nests in 2024 were located in oak trees. So far, the storks have not branched out beyond the main colony at Knepp, but we are optimistic that this will happen in the near future as the population grows.
As we look ahead to the next breeding season, predictions are already being made about the number of nests and eggs we might see. However, the storks face several challenges before that time. Over the winter, nests often suffer damage or are completely destroyed by harsh weather. Fortunately, storks are quick to rebuild or repair their nests in spring.
Many of the adults are migratory, which adds another layer of complexity. They must navigate back to the colony and hope that their partner has made the same journey safely. Storks typically (though not always) remain with the same mate for many years, so for the migratory birds, we hope both partners return safely to resume their roles in the nest.
