BIJLSMA RG (2013) Silent winter: the loss of birds from Veluwe's arable land. LIMOSA 86 (3): 108-121.

The Veluwe region in the central Netherlands is typified by coarse nutrient-poor sandy soils and a groundwater table of >140 cm below the surface. The area is mostly forested, with arable land interspersed. From times immemorial, farmers used cropping systems revolving around cereals and root crops. This study on the south-western Veluwe (100 km²) documents the vicissitudes of birds on arable land in winter, and changes in farming practices, between 1969 and 2010. In this 40-year period, 57 bird species were recorded using arable land in January-February, declining from >40 species in the 1970s to some 20 from the mid-1990s onwards. Bird density declined steeply from up to 1814 birds/km2 in the mid-1970s to 64 in 2010. Biomass declined from a maximum of 265 kg/km2 in 1976 to 10 kg/km2 in 2010. This decline was evident in all bird families typical of arable land in winter: galliforms, gulls, pigeons, larks, thrushes, corvids, Starling Sturnus vulgaris, sparrows, finches and buntings. In numbers (19%) and biomass (50%) Woodpigeons Columba palumbus were the single most important bird species on arable land (stubble). Their numbers peaked in July, gradually declined in the course of the winter and crashed when spilled grain density fell below a threshold of 100 grains/m². Numbers of avian predators (0.9% of all birds present) using arable land did not change much over time, ruling out predation risk as a factor in the decline of farmland birds. Of nine raptor species, only Falco tinnunculus declined consistently, corresponding with a decline in Common Vole Microtus arvalis numbers. Profound changes in land use are the common denominator for the demise of wintering birds in arable land on the Veluwe. The switch from spring-sown to autumn-sown cereals (reducing the duration of stubble availability in winter), the advancement of the cereal harvest by more than a month between 1969 and 2010, the switch from cereals to maize as bulk crop in the late 1970s, use of herbicides (reducing natural seed stocks) and the improved efficiency of cereal harvesting converted the fields into wasteland. In the 1970s, the grain stock was steadily depleted by birds and voles from a high just after harvest to a low in late winter. Relative densities of Common Voles remained steady until grain densities dropped below 50 grains/m². Density of spilled grain on stubble in July-September declined from 250- 500/m² in the late 1960s and early 1970s to near-zero from the 1980s onwards.
      Cereal stubble attracted the majority of wintering birds, i.e. on average 71% of the twelve most common species in 1969-2010 (on 28.4% of the acreage). Given this preference, and the above changes in farming practices, the 96% loss of wintering birds on farmland on the Veluwe is no surprise. It is reflected by an 80% loss in biomass of breeding birds in the same region. Recent trends in farmland use, notably conversion of arable land into 'new nature', did not counter the decline in farmland birds; after an initial dynamical phase these fields became obsolete for farmland birds as a result of either intensive grazing (conversion into grassland) or natural reforestation.

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