Despite these measures, breeding birds whose nests in open farmland are protected against mowing, fattening and grazing have produced relatively fewer young in recent years. The so-called ‘nesting success’ of these birds decreased from 60 to 40 percent between 2012 and 2019, reports the CBS in collaboration with Sovon Bird Research Netherlands.
The measures to protect the nests of these groundbrothers, including the black-tailed godwit and lapwing, must preserve the population of the birds. The nests that are protected are often in areas with agricultural nature management (areas where, for example, no mowing is done during the breeding season) and sometimes also in regular agricultural areas.
As of 2000, the nesting success of six species of birds breeding in open farmland has been recorded: the black-tailed godwit, lapwing, oystercatcher, shoveler, redshank and curlew. In 2012, 60 percent of the nests of these birds produced at least one young, in 2019 this was just above 40 percent.
The nesting success of six farmland birds that nest in farmyard and thicket environment was also recorded. Their nests, which the animals build in stables or shrubs, for example, are not protected and have had a nesting success rate of about 80 percent for years.
The possible cause of the decline in the nesting success of the ground brothers, according to CBS and Sovon, is to be found in the weather conditions and that more eggs and chicks are eaten by other animals. Although the nests should be protected against this, trampling by livestock and manure or mowing are also cited as the reason for the decrease.
Farmland bird population has been declining for decades
Despite the measures that have been taken with regard to agricultural nature management, according to the organizations, studies show that the chicks that do emerge from the nest are less likely to survive than before. “Partly as a result of declining nesting success and the lower chances of survival of the young, the populations of farmland birds have been declining in size for decades,” according to the CBS.
The decrease in the population is greatest among the ground breeders, but the population has also decreased among the six farmland birds that build their nests in barns and bushes. According to the researchers, this may be partly due to the decline in insect biodiversity.
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