About Yellowhammers

The Yellowhammer is a ground-feeding member of the bunting family that favours arable and grassland habitats during the breeding season and that typically nests on the ground at the base of hedgerows and bushes. It has a wide European distribution, extending from Northern Spain to Northern Scandinavia in the west to northwest Russia and Greece in the east.  During the Bird Atlas 2007-11, the UK breeding population was estimated to be 1.5 million pairs: this is believed to be the third largest in Europe with only Germany and Finland supporting larger breeding populations.

Most Yellowhammer populations are partly migratory, with the UK population, particularly along the east coast, augmented by birds from Scandinavia in winter. The UK Yellowhammer population, however, is considered largely sedentary, with ringing recoveries suggesting that most birds stay within 7 km of their breeding territories and few birds moving more than 50 km.  This means that feeding habitats need to be available all year to sustain the UK population.

Originally, Yellowhammers are thought to have occupied open woodland habitats such as woodland edge, rides and clearings but avoiding dense forest.   Now they are strongly associated with agricultural habitats, especially cereal crops and food-rich grassland habitats.  In optimum habitats they achieve densities of c.22 pairs per km2.  They also breed on ‘bushy’ heaths and commons, particularly in areas with gorse scrub.  Most importantly, Yellowhammers need open ground for foraging throughout the year.

During the breeding season their diet comprises a mix of cereal seeds, grass seeds and, to a lesser degree, invertebrates.  In winter, they become even more dependent on agricultural habitats, particularly weedy stubble fields, root crops and, historically, farmyards with grain stores.

The extent as well as the quality of the cereal crops in the landscape impacts on the survival of Yellowhammer populations and several factors have contributed to the decline of Yellowhammers in the UK.  Declining winter food resources, i.e., the loss of weedy food-rich stubbles, are thought to be a critical factor.

Other key factors include:

  • The loss of most species-rich grasslands/hay meadows in the UK countryside:
  • The replacement of small weedy arable fields by species-poor permanent grass leys seeded for silage production:
  • Increasingly efficient seed cleaning techniques have removed seed contaminants from cereal seed supplies and contributed to the general loss of ‘weediness’ in fields:
  • The widespread adoption of herbicides and pesticides intended to eradicate the arable plants formerly associated with cereal crops. The seeds of these plants are an important part of the farmland bird diet:
  • The development of highly nitrogen-responsive crops that grow quickly and vigorously and shade out any arable plants that have survived spraying:
  • Massive increases in nitrogen applications that aid the growth of cereals and enable them to outcompete other plants present:
  • A culture of maximum production that involves planting and spraying to the edges of fields. This all but eliminates arable plants from the field margins; an important habitat for seed-eating birds like Yellowhammers and Grey Partridges:
  • The change from spring to autumn sown cereals. This reduces the potential for weedy winter stubbles in the landscape:
  • The loss of mixed farming systems and changes in crop rotations. This further reduces the area of arable habitat in the countryside and potential sources of seeds for farmland birds:
  • ‘Farm Assurance’ measures for minimising the number of vermin on farms. These measures reduce the amount of spilt grain in farmyards and deprive Yellowhammers of another former source of winter food source.