This finding comes from newly published research (Santangeli et al 2019) which considers Finland and its wild bird population.

Researchers used six years of data on 46 bird species from the Finnish landscape. They found that organic livestock farms support both migratory birds and insect-eating birds. Of all the supposed biodiversity-boosting farmland measures supported by EU via the Common Agriculture Policy, organic livestock farming was the only one that significantly correlated with higher numbers of wild birds.

In fact, organic livestock farming also out-performed organic cereal farms.

The researchers assessed the country-wide impact of several CAP AES measures on bird abundance, and found “a positive impact of organic animal farming on abundance of all farmland associated birds”.