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Plastic instead of straw: Storks use human waste to build nests

26.06.2023: Human-induced environmental pollution has a significant impact and even influences the nestbuilding of birds. This is shown by a recent European study led by the Konrad Lorenz Institute of Ethology at Vetmeduni using storks. However, the use of human waste differs significantly between individual stork populations.

Two major consequences of the ever-increasing human expansion are the conversion of natural habitats into agricultural land and the expansion of built-up areas. Related to this, human waste is also found just about everywhere. This has serious implications: Plastic pollution, in particular, is impacting wildlife worldwide. Discarded plastic is ubiquitous and increasingly a material for birds to incorporate into their nest structure - as now shown by a European research team from Spain, Poland and Austria using the white stork (Ciconia ciconia) as an example. In their study, the scientists describe the type, frequency and amount of anthropogenic nesting materials in two populations of the white stork in two geographically distant breeding areas, namely in Poland and in Spain.

Poland is not Spain: Significant differences in the use of plastic

In the total of 303 nests of the two populations, the researchers found significant differences in the use of anthropogenic nesting materials. To explain the reason of this, the scientist:in used remote sensing data from the Human Footprint Index (HFI) and the proportion of Impervious Surface Areas (ISA) - covered by buildings, roads and similar man-made structures. "We found that both ISA and HFI were positively related to the amount of anthropogenic nesting materials in the Spanish population. In contrast, there were no statistically significant correlations in the Polish population," said study final author Marcin Tobółka of the Vetmeduni's Konrad Lorenz Institute of Ethology. In addition, the researchers:in were able to demonstrate that the use of anthropogenic nesting material in Spain was twice as high as in the Polish white stork population.

Habitats: Variation in human footprint as a major factor

According to the study, the different human footprint HFI values for the Spanish and Polish study sites reflect different levels of human pressure on natural habitats. As a result, the Spanish white stork population inhabits more urbanized areas. In contrast, the Polish population remains a farmland bird and inhabits mainly areas with semi-natural meadows and pastures.


The article "The prevalence of anthropogenic nest materials differs between two distinct populations of migratory birds in Europe" by Zuzanna Jagiello, Łukasz Dylewski, José I. Aguirre, Joanna T. Białas, Andrzej Dylik, Alejandro López-García, Ireneusz Kaługa, Adam Olszewski, Joachim Siekiera and Marcin Tobółka was published in Environmental Science and Pollution Research.

Scientific article