Swiss Bird World Consists Mainly of Chickens
The Swiss bird world is dominated by poultry. For every wild bird species, there are dozens of chickens kept in intensive farming.
The total weight of Swiss poultry is 15 times higher than the weight of birds breeding in the wild.
The proportion of wild birds in the bird biomass is thus significantly lower in Switzerland than in global comparisons. This is what researchers write in an article in the specialist journal «Ornithologischer Beobachter».
The total number of all wild birds in Switzerland amounted to around 20 million individuals in 2016.
These weighed a combined total of around 1’100 tonnes. By contrast, 12.5 million individual poultry animals weighed a combined total of around 16’000 tonnes. The broiler chickens, laying hens and breeding chickens alone had a combined weight of around 15’000 tonnes in 2016.
This means that wild breeding birds account for only around 6% of the total bird biomass in
Switzerland. This share of wild birds is significantly lower than the global figure; worldwide, the
proportion of wild birds in total bird biomass is around 30%.
Over the past 20 years, the biomass of poultry in Switzerland has increased by around 40%. The biomass of wild birds also increased during the same period, though by significantly less at around 20%. Among wild birds, the wood pigeon, carrion crow and common blackbird contributed the most to the increase in biomass. These three common and relatively heavy species together account for one third of the total mass of wild birds in Switzerland. Over the past 20 years, the biomass of breeding birds in alpine habitats and in villages and towns has declined.
Poultry production in Switzerland is likely to continue growing due to rising demand. Consequently, the proportion of breeding birds in Switzerland's total bird biomass will probably continue to decline, the researchers write. However, poultry production comes at a high ecological cost, as it is heavily dependent on imported concentrated feed from abroad. Without feed imports, only 17% of current poultry in Switzerland could be kept. Furthermore, higher poultry production increases the burden of nitrogen compounds. Ammonia and other compounds are produced during the decomposition of animal excrement, are distributed widely through the air, and threaten nutrient-poor ecosystems such as lean meadows or bogs through unwanted fertilisation.
For their calculations, the researchers used data from the Federal Statistical Office as well as data
from the Swiss Breeding Bird Atlas, collected between 2013 and 2016 by more than 2,000 volunteers.
