Birds in the Małopolska gorge of the Vistula River
We present birds in the Vistula gorge in Lesser Poland, endangered species, methods of their protection and threats to birds in the Vistula valley
The birds that nest on the Vistula are threatened by many dangers. Year after year, the problem is intensifying, with the result that the numbers of some species are declining at a drastic rate. A very good example of this trend is the Common Gull. In the 1990s, there were as many as 3,500 pairs of this species nationwide. In 2021, there were only 440 pairs, of which only 287 pairs in the entire Vistula Valley. These are alarming figures that show how much a comprehensive program is needed to protect this and other species of waders on the Vistula. The Common Gull is just an example. A similar situation applies to the Mediterranean Gull, Ringed Plovers and Oystercatchers.
The breeding birds of the mentioned species are threatened primarily by:
- predators – corvid birds, American mink (vison), foxes, dogs, cats and other mammals of prey.
- floods and raised water levels on the Vistula – over the past few years, the Vistula has regularly raised its level during the breeding season, taking most of the birds’ nests with it
- loss of nesting habitat – bird nesting islands on the Vistula River are very quickly overgrown with expansive vegetation (mainly willow and ash-leaf maple) taking away places where birds could nest; transformation of river channels (e.g., dredging, removal of millings or connecting islands to the land), construction of dam reservoirs and dikes; disappearance of pastures which contribute to the overgrowth of islands.
tourists, anglers, kayakers and Sunday strollers – many people are unaware of how much they endanger the birds by stepping onto the islands where the nests are located. Eggs are smashed by ATVs, trampled by people, overheated on a hot day or chilled at night when a tent is pitched nearby. Humans on swales is currently one of the most serious problems, which is very difficult to combat.
The European Oystercatcher (Haematopus ostralegus) occupies a vulnerable status in the „Red List of Birds of Poland”. It is a breeding species in our country, but it occurs in small numbers. The European population is about 284-345,000 pairs, but due to the rapid decline of the oystercatcher globally, it is considered a near-threatened species. It inhabits the Palearctic from the islands and Atlantic coasts of Europe through the inland parts of Eurasia to eastern Kazakhstan and isolated breeding grounds in eastern Asia. The first Oystercatchers in the 1930s occupied several breeding sites between the Rega estuary and Ustka. After withdrawing from these sites, the species began nesting again on the Polish coast in the 1970s. The first Oystercatcher breeding in the Lublin region was recorded in 1982 on the Cow Island near Kazimierz Dolny. In the early 1990s, the breeding population in the country was 16-18 pairs.
In 2020, it was about 30-35 throughout the country (Central Vistula Valley – 14-16 pairs, Lesser Vistula Gorge 7-9 pairs, 4-5 pairs in the section from the mouth of the Vistula River to Annopol, 4 pairs in the Lower Oder Valley and 1 pair at the mouth of the Warta River). 95% of the European population is a nominate subspecies, most of which is concentrated in the North Sea region. Unfortunately, in the last dozen years or so, a clear regression of this subspecies has been noticed. Besides, the same is true of the longipes subspecies, which mainly inhabits eastern Europe (Russia, Belarus, Ukraine, Lithuania). In our country, as in the case of the other species protected by the project, every year the greatest threat to the breeding of these birds on the Vistula River is increased water levels and flooding. Predation, people, hydraulic engineering works, i.e. everything we described in the section on threats, has a very negative impact on the survival of oystercatcher breeding. It is interesting to note that the oystercatcher is one of the longest-lived waders, as long as it is not hunted by a predator beforehand.
The Common Gull (Larus canus), is a species of medium-sized gull with a fairly extensive distribution range. Breeding Common Gull are found from the British Isles, through the Scandinavian peninsula, central and eastern Europe to the Urals. The largest breeding colonies on the continent are in Russia, the Scandinavian countries, Great Britain, Denmark and Germany. In our country, this gull nests irregularly mainly on the Vistula River and in a few dozen sites in the rest of the country, mainly in Silesia and Lesser Poland. This beautiful species of gull is rapidly declining in number in Poland.
Back in the 1990s, it was estimated that there were 3,200 – 3,500 pairs in the country. In 2013-2018 it was only 600-1000 pairs. In 2021 it is only 440 pairs, of which 287 pairs concern the Vistula alone. Such an alarming decline in the number of this species requires every effort to halt the decline, and if there is a possibility, to help the birds increase breeding success. An interesting fact about this species is that this gull has begun to establish nests on the roofs of buildings in cities.
The Mediterranean Gull (Ichthyaetus melanocephalus), currently occupies the status of endangered in the „Red List of Birds of Poland,” but its rapid decline combined with a small population size qualifies the species as critically endangered in our country. The status of „endangered species” was obtained only because of the possibility of feeding the national population from neighboring countries. The vast majority of the world’s Mediterranean Gull population is concentrated on the Black Sea coast of Ukraine. The remaining sites are widely dispersed throughout Europe, with the largest local populations in France, Russia, Italy, the Netherlands, Turkey, Greece and Belgium. The first breeding of this species in our country was recorded in 1981 on the Vistula Lagoon. Gradually, the species increased its numbers. In 2000-2005 it was only 18-30 pairs in Poland. In 2007 it was already 97 pairs. However, gradually this number began to decline. In 2019 there were only 42 pairs nesting in Poland.
Unfortunately, all the previously mentioned threats do not improve the situation of this gull in the country. In addition, in the case of this gull, there is a threat from the declining population of the Mediterranean Gull, in whose colonies Black-headed Gulls nest. An interesting fact about this species is the synchronization of breeding. Chicks in one colony hatch almost simultaneously. Unfortunately, in our country it is difficult to talk about Mediterranean Gull colonies. Its breeding is sporadic and only detectable by specialists.
The Ringed Plover (Charadrius hiaticula) currently occupies the endangered status in the „Red List of Birds of Poland”. Its population is small and steadily declining. In Poland, the Ringed Plover currently nests in a few scattered sites on the Baltic coast. and the main part of the national population occurs in the Vistula and Bug river valleys. In the 1980s, the national population of this species was estimated at 350-400 pairs. In modern years, it is of the order of 220 pairs. The range of the Ringed Plover in Poland has also been greatly reduced over the last 50 years. Most of the sites on the Baltic coast have disappeared and the species has also retreated from the Warta, Pilica and Narew rivers. In the world, the breeding grounds of the Ringed Plover are distributed along the coasts of the northern Palearctic, from Great Britain, Iceland and Greenland through all of Siberia to Chukotka.
In some countries, the species nests inland away from the sea coasts – in Scandinavia, Iceland, locally the UK and central Europe (Poland, Belarus and Ukraine). Unfortunately, as many as 50% – 60% of young plovers die in their first year. In subsequent years, mortality drops to 20% – 30%. The decline in the breeding population of this species in the country is mainly due to the loss of breeding sites and low breeding success rate. And all this is caused by the threats mentioned above.
Return messages from aviary birds
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