OTTENS HJ, WIERSMA P & KOKS BJ (2013) Winter food for farmland birds in Groningen and Drenthe. LIMOSA 86 (3): 192-202.

Modern agricultural fields have little to offer for wintering birds, which has resulted in dramatic declines in numbers. Since 2008, in the provinces of Groningen and Drenthe, in the northern Netherlands, many volunteers have monitored winter birds in agricultural fields. The aim was to quantify the effect of winter food fields (WF fields), a newly introduced method of agri-environmental nature management. These 0.5 to 2 ha fields are sown with various cereals and other seed bearing plants with the aim to offer food for wintering birds such as Yellowhammer and Skylark. In 2012, 238 ha of WF fields were established in the two provinces. The number of species reported was higher in WF fields (64) than in control fields (41). Also, numbers present were much higher in WF fields than in controls (maximum numbers: 255 vs. 55). The most numerous species were Greenfinch and Yellowhammer, making up 63% of all birds. Numbers, including those of vole consumers, were highest from November to February, except for Skylark, which peaked during the migratory seasons. Bird numbers increased with WF field size but densities declined as fields became larger. Lower temperatures led to higher numbers of finches, buntings and vole eaters. Snow depth was positively correlated with number of finches, buntings, sparrows and gallinaceous birds and probably also of larks and pipits.
      Our results show that WF fields are of great importance to birds wintering in agricultural fields. We hypothesize that the recent increase in numbers of Yellowhammers breeding in East Groningen may have partly resulted from these management efforts. For Skylarks, however, a positive effect may be limited by the presence of shrubs and trees, which are important for most other birds.

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