Further evidence of the importance to birds and farmers of hedges in agricultural land comes to us from a rather unlikely source. Studies from Akot, Maharashtra State in central India revealed how strong the difference in bird numbers and diversity between different farmland sites with and without hedges can be. Hedges in the study area were shown to provide important nesting, feeding and sheltering sites for birds in agricultural areas with highest numbers of birds in those fields with hedges.
During the Indian study, 64 bird species from 34 families were observed. Most of the birds were recorded actually in or very near hedges. An earlier study (here) in Germany reported that increasing hedge length enhanced significantly the number of bird species and that adding hedges or introducing organic farming practices should be primarily promoted in simple landscapes, where it really makes a difference for biodiversity.
These studies show that hedge length has a stronger effect on bird richness than management and that the increasing length of hedges enhances birds in conventional, non-organic, fields too. Bird conservation even in intensively used agricultural landscapes should concentrate on hedges or green lanes.
Providing more hedgerows and carefully managing them, can significantly contribute to the conservation of declining farmland birds. Birds forage in the agricultural fields, using the hedges for resting and breeding. Highest diversity of birds was also directly connected to diversity of plants as the greatest number of plant types gave more choice of food for the bird species. High numbers of bushes and plants at the boundary of agricultural land will benefit the largest numbers of birds. Thus planting trees in agricultural lands and well managed hedges can increase the bird diversity and large scale cutting of hedges should be avoided.
Not only will populations of birds benefit from increased hedges but the birds can themselves benefit the farmer. Insectivorous and predatory birds play a very useful role in controlling insect and rodent pests of crops. Presence of healthy numbers of birds in the farm fields is an eco-friendly and useful way of controlling the pests on the crop so, hedgerows must be saved to conserve farmland bird diversity. Hedges should, however, be maintained properly and not allowed to become invasive and reduce the utilizable area of the field.
Studies on farmland avian diversity with special reference to importance of hedges in conserving farmland bird diversity can be downloaded here.