Researchers: every year, cats kill millions of small mammals and birds in Poland
Scientists estimate that approximately 631 million mammals and almost 144 million birds in Poland fall victim to cats every year. They emphasize that cats’ activity has a negative impact on biodiversity and on endangered species of birds.
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Estimates concerning the number of animals being killed by cats in rural areas in Poland were carried out by: Dr. Dagny Krauze-Gryz from the Warsaw University of Life Sciences (SGGW), Dr. Jakub Gryz from the Forest Research Institute in Raszyn and Dr. Michał Żmihorski from the Mammal Research Institute of the Polish Academy of Sciences (IBS PAN). The results of the research were published in "Global Ecology and Conservation" (https://doi.org/10.1016/j.gecco.2018.e00516).
Their calculations show that rural cats bring home and eat 48.1 and 583.4 millions of small mammals, respectively, and 8.9 and 135.7 millions of birds, respectively on an yearly basis.
In the case of birds, those species that nest close to human settlements are most likely to fall victim to cats. These are, for example, sparrows, tree sparrows or starlings – species that are generally decreasing in numbers throughout Poland. Birds that nest on the ground, such as yellow wagtail, skylark or whinchat, are also exposed to cat attacks. Studies conducted in England indicate that cats are responsible for the death of 30 per cent of sparrow population there. Cats can also affect birds indirectly. American research shows, for example, that the stress caused by their presence may reduce fertility in birds.
"It was known that cats kill a lot, but the estimates surprised even us. Precise estimation is always a problem in such situations, but the data we have collected indicate these numbers"- says Dr. Michał Żmihorski from IBS PAN.
Dr. Dagny Krauze-Gryz from Warsaw University of Life Sciences (SGGW) notes that more and more has been said and written about the problem of cat predation on wide life. This is due to the fact that the number of cats is constantly growing and is correlated with the number of people. At the same time, the researcher points out that Poland's rural areas constitute an important bird sanctuary (also on a European scale). However, their numbers are decreasing, mainly due to changes taking place in the agricultural economy.
"Our research has shown that cats in the countryside are another factor that may threaten birds and other vertebrates in these areas" - emphasized the researcher.
The authors of the publication remind that about 94 million breeding pairs of birds live in Poland (this is the total number of all species). They showed that cats in the villages can kill a very large percentage of this number. Most birds are caught and killed by cats during the first months of the spring and the least in November. This suggests that young birds fall victim to cats, which may limit the productivity of bird populations.
Dr. Krauze-Gryz points out that cats in the countryside are not treated as household pets - they are kept mainly to catch mice. "Probably because they are very poorly fed - and sometimes not at all, leftovers that do not satisfy their nutritional needs, which forces them to hunt," he says.
The expert adds that the world is taking actions to make people aware of the negative impact of their cats on the fauna. Attention is also paid to the dangers to which cats that go outside are exposed, e.g. to the risk of accidents on roads. "However, in the case of Poland, it is difficult to act effectively, since the care of many cat owners for their well-being is very limited," says the scientist from the Warsaw University of Life Sciences.
"According to our observations, cats in the countryside are often neglected, poorly fed, have to hunt to survive. This is the result of the owners’ ignorance or simply ignoring the nutritional needs of the cats" - confirms Dr. Żmihorski.
The authors of the study postulate educating cat owners who know little about the harmfulness of their animals. "We also suggest introducing legal solutions that - just as in the case of dogs - would limit the possibility of cats moving freely and hold owners responsible for damage caused by their cats to the environment," says Dr. Żmihorski.
According to unofficial data, about 6 million cats live in Poland. Only some of them are typically domestic cats kept indoors. The rest are feral cats living permanently outdoors or indoor cats whose owners let them explore the outside world from time to time.
Source: Science in Poland, PAP
