Project "From The Wisłoka To The Wieprz - active protection of endangered bird species in the valley of the Wisla river"
Active protection of waders
The Bird Horizons Foundation has developed a comprehensive program for the active protection of selected species of waders covered by the project "Od Wisłoki do Wieprza - active protection of endangered bird species in the valley of the Vistula River." This program is divided into several stages:
- Monitoring and searching for nests of four bird species covered by the program (Oystercatcher, Common Gull, Mediterranean Gull, Ringed Plover)
- Planting dummy eggs and securing real eggs of selected bird species in the foundation’s incubators
- Returning hatchlings to their parent nests
- In a situation where there is nowhere to give the chicks – rearing them in foundation aviaries
- Release fully flighted and ringed birds into the wild.
The program for the active protection of endangered species of waders that the Bird Horizons Foundation has developed involves searching for the nests of these birds, securing the eggs in incubators, placing dummies and rearing the aviary portion of the chicks. Finding a nest early is important to effectively protect it from predators or destruction during floods. These activities are carried out from mid-April, the beginning of the egg-laying period, until the end of June, as some pairs repeat breeding.
In the case of Common Gulls and Oystercatchers, known sites from previous years and adjacent islands are checked first. In the case of Oystercatchers, it is worth knowing that they are long-lived birds and return to the same breeding grounds every year. The coordinates of the nests found are recorded in the GPS receiver. Once the nest is found, the eggs are transferred to incubators and are replaced with wooden dummies that look like the original eggs of the treated species. This is an effective method to reduce losses at this crucial stage of breeding. The task can be divided into two stages: putting artificial wooden eggs into nests and incubating the eggs in an incubator. The eggs of endangered waders are transported in a portable incubator.
Use of portable incubators
Incubation of all found hatchlings is carried out in an automated incubator with movable trays or rollers, where the eggs are rotated and constant temperature and humidity are maintained. The development of the embryos is observed with an ovoscope. When hatching occurs and the voices of the chicks can be heard, the eggs are transferred immediately to the mother nest, from where the birds’ incubated dummy eggs are taken, or (in the case of adverse weather conditions) they are placed in the hatcher. Then already hatched chicks are put into the nest. In this way, the eggs of birds during the incubation period are not threatened by predatory mammals and birds. In the case of penetration of the islands by tourists in hot weather, there is also no risk of overheating the eggs from which the frightened birds have descended. The eggs are also protected from destruction during floods (recent years recorded high water levels every year). The operation of the incubators is monitored daily (temperature, humidity, egg turning system, air circulation, sanitation, etc.).
Monitoring the work of incubators
The development of embryos in the eggs is also controlled (x-raying the eggs, checking for water loss). At the stage of shell bursting – hatchlings are transferred to hatchers, after the eventual hatching of chicks are provided with optimal conditions for their development (temperature, humidity, air circulation, sanitary conditions) until they are transported to the nests from where they originated. The efficiency of egg hatching is, depending on the species at the level of 94%-99% (fraction of eggs in which the embryo developed) i.e. even higher than naturally in the field, where the proportion of unfertilized and/or unhatched eggs is usually at the level of no less than 8-10%.
In cases where the pair abandons the nest during incubation (e.g., due to the selection of wooden dummies from the nests by a fox or crow) or the nest is flooded (annually recorded cases), or there is a high risk of death of the hatchlings (e.g., a breakdown in the weather, an impending flood) they are destined for aviary rearing. The chicks of the species of piping plovers selected for the program are easy to rear and do not become attached to a caretaker (no imprinting).
Chicks after hatching
During the first weeks of life, they are kept in an enclosed room (breeding aviary), on heating mats or under a lamp (so-called artificial brooder). The chicks are fed specialized food for plovers and invertebrates: whitefly larvae, earthworms and small locusts. After a week, the young are placed in an outdoor adaptive aviary. Once the young are volatile, they are released on benches and islands in the Małopolski Przełom Vistula River in suitable habitats, in areas from where the eggs were taken. Similar measures have been successfully used in Poland for the great curlew or gray gull. Aviary breeding and releasing young oystercatchers, ringed plovers and black-headed gulls was developed and applied by the Bird Horizons Foundation as the first in the world. In Poland, the Bird Horizons Foundation is a pioneer on such a large scale and in such a species range.
Previous experience on waders indicates that the danger of rejection of artificial eggs by Vistula waders is negligible. To date, there is no basis for the claim that the presence of dummies in the nest has ever been a cause of brood abandonment by birds under this treatment. Members of the Foundation mark the released flying birds with special ornithological rings, which allow us to identify the birds in the field. This allows us to monitor the effects of our work and keep track of the birds that have been raised in the foundation’s aviaries.
Maintenance of nesting habitats
The Vistula islands are becoming more and more overgrown every year. This is mainly due to expansive plant species such as willow and ash-leaf maple. There are also a lot of tall annual plants on the islands, such as nettle and goldenrod, which disturb the birds nesting in the area the following breeding season.
There used to be cattle grazing on such islands (Cow Island Reserve is an example). This prevented plants from having a chance to grow. There were also more birds on such islands. Contrary to appearances, cattle and birds did not bother each other. Nowadays, such grazing is no longer practiced. The cost of keeping the animals and transporting them to the islands is very high. The aforementioned Cow Island used to be teeming with bird life.
Nowadays, there is no longer any place for plover birds on it. One might be tempted to say that this island is now inhabited mainly by larks, crows and foxes. If we want to save other islands from such a state, it remains to manually clear their area of expansive plants. Of course, if one has the funds, it would be as good an idea as possible to introduce grazing on the islands. As part of the project, two Vistula islands have been treated for clearing their breeding grounds of fast-growing plants. A large island near Zastow Karczmiski and an island near Kaliszan Kolonia. By stopping the expansion of plants, we are able to preserve these extremely valuable areas for birds. We know that this brings results.
We are doing similar work in the Subcarpathian region on two nesting islands in areas reclaimed after a sulfur mine – one is a colony of white-headed gulls and the other is a colony of blackheads. Thanks to the work of volunteers, the number of nests on the islands there is steadily increasing every year. If we introduce similar measures on the Vistula there is a chance that we will maintain the most valuable nesting habitats of rare bird species.
Monitoring and combating the American vison
One of the most effective predators that threatens bird nesting is the Vison, or American mink. It is a species that is native to North America. The Vizon is an example of very drastic human interference with the environment. This seemingly nice and friendly animal is an excellent killer of birds and many other animal species.
The American mink was brought to Europe as a furry animal. Wild populations of the species appeared in Europe in the 1950s, as a result of the release of many individuals in the former Soviet Union, as well as the escape of individuals from fur farms. As a result, the species has established a wild population that is steadily expanding its range. In Poland, the American mink has become a permanent part of the fauna since the early 1980s. Currently, the range of occurrence covers almost the entire area of Poland, excluding its southern extremities. The American mink reproduces freely in the wild. The great plasticity of this species’ biology allows the mink to adapt to a wide variety of environmental conditions. Its presence in an area is associated with a rapid decline in the numbers of many native animal species, including birds, among others. It causes large losses in the economy and poses a threat to humans through the transmission of various diseases.
It has also been proven that vison can negatively affect the abundance of a native species, such as the European mink.
Genetically modified and less adapted to the environment, when crossed with the European mink, it can pass on defective genes thereby causing a reduction in the national population or even its complete extinction. It has been declared an invasive species, and the hunting season for the American mink lasts all year. Monitoring large bird breeding colonies on the Vistula islands, more than once we have seen signs of the vison’s presence nearby. One such individual can knock out an entire colony of birds. It usually eats only the brains from hunted adult birds, but it will not disdain eggs and small chicks either. To give endangered bird species a chance, we need to start a war against this species. The only effective method is to capture individual birds from a given revir. The Bird Horizons Foundation, as part of the project, is implementing measures to reduce this species in the environment, near key bird colonies on the Vistula. As part of the projects, 10 cages for trapping the vison have been purchased. These activities will be carried out until 2024.
From August 20 to September 20 in 2022 and in 2023, the project will conduct an ornithological camp at the foot of a picturesque quarry in Piotrawin on the Vistula River. The quarry is located on a 40-meter limestone escarpment near the banks of the Vistula River.
Ornithological nets for trapping birds will be set up in the Vistula River bluff at its foot. During the course of the camp, birds will be collected from the nets every hour into special bags and carried by camp participants to the ringing base, and will be ringed by ornithologists. To the ornithological camp we invite organized groups from schools, cultural centers, nature circles, senior citizen clubs and other communities, as well as all those who are not indifferent to the fate of birds. During the camp we will educate both in the field of bird marking and active protection of birds. We will tell about our activities and show participants what working with birds looks like. Participants of the camp will learn to identify species of birds that can be found in the Malopolski Przełom Vistła, learn about the migration routes of some species of birds, learn about the methods of their research and the purpose for which it is carried out, learn about the methods of active protection and find out why you can’t enter bird nesting islands on the Vistula (and not only). The camp conditions will additionally make the stay more pleasant for all those who want to get away from everyday life. Each group is provided with refreshments during their one-day stay at the camp. For eager thrill-seekers, there are prehistoric fossils waiting to be discovered in a nearby quarry.
PTASIE HORYZONTY FOUNDATION was established by passionate people who have been researching and actively protecting nature in the Lublin region for many years.
PTASIE HORYZONTY FOUNDATION
ul. Spółdzielcza 34,
24-220 Niedrzwica Duża
NIP: 713 310 52 79
tel. 519 801 302; 535 571 818