Most farmland bird species in lowland Britain feed on seeds during the winter, however many have suffered major declines as the mixed farming practices which once provided winter seed food have reduced.
Areas of seeding rye grass can provide valuable winter food for seed-eating birds such as yellowhammer.
What
Closing up ryegrass-dominated grassland from cutting and grazing in the summer and leaving ituntouched until March when it can be brought back into production.
Why
In regions specialised in livestock production, especially in the lowlands, swards dominated by agriculturally productive rye grass (Lolium perenne) plants are common. Under normal agricultural management, these swards provide very little for wintering seed eating birds to eat.
However, this can be changed by modifying management so that some of the ryegrass is allowed to set seed in summer. Rye grass seeds are large, abundant and easily collected by birds, making them a valuable food source. There are few other grasses with these qualities.
Seeded rye grass provides a means for grassland-dominated farms to provide winter seed food where ‘arable’ winter food options such as cereal stubbles are not practical.
Seed-eating birds such as yellowhammers and reed buntings will be attracted to seeded rye grass, and other birds such as corn buntings, skylarks, and gamebirds can also benefit. It may also benefit other farmland wildlife, including invertebrates and small mammals.
Seeded rye grass is particularly beneficial in late winter, continuing to provide seed food into March when other sources of seed food have been exhausted. This late winter/early spring period is sometimes referred to as the ‘hungry gap’, a period when seed food is in shortest supply for wildlife.
How
This type of management should be targeted at grasslands with a high (>75%) rye grass content. These are most likely to be fields recently reseeded with a rye grass-dominated mix. Perennial, Italian or hybrid rye grasses can all produce suitable seed, but Italian and hybrid rye grasses provide a more consistent source of winter seed food.
Usage by birds is positively related to seed head density - Italian and hybrid ryegrass plots can produce seed head densities exceeding 500/m2.
Seeded rye grass can be created on a whole or part-field (by leaving plots or strips uncut or ungrazed). As seed densities are generally lower on the edges of fields, any strips created on the field edge should be at least 10m wide and situated away from busy roads which disturb birds.
Strips will attract different bird species depending on where they are located. For example, buntings prefer plots near hedges, but open-country birds like skylarks prefer plots away from hedges and trees.
Managing the grass to produce abundant seed
For rye grass to produce large seed crops that will attract birds (ideally more than 400 seed heads/m2), there will be a need to forgo cutting or grazing from mid-summer. The timing will depend on which rye grass species dominates the sward.
- Perennial ryegrass - Cutting/grazing needs to cease by the 3rd week of May for perennial ryegrass to produce adequate seed. This could allow one silage crop to be taken in southern Britain. In the north of Britain, plant growth is slower so grazing may need to end earlier in order to produce seed.
- Italian and hybrid ryegrass - Cutting/grazing needs to cease by the end of June to produce adequate seed so potentially two silage crops can be taken.
Once cutting or grazing has ceased for the year and the rye grass has gone to seed, it is important to avoid disturbing the vegetation, for exampleby moving animals through it. This will dislodge seeds, which will then become less accessible to foraging birds and rot on the ground.
Birds will continue to use seeded rye grass into March and April, much later than wild bird seed mixes which are often exhausted of seed by January.
Restoring the area to productive farming
Unless the seeded ryegrass plot is due to be cultivated in spring, the thatch of vegetation remaining at the end of the winter will need to be removed. This can be done by mechanical means once soil conditions allow eg mowing and clearing cuttings or by grazing hard. Dislodged rye grass seed may germinate in the spring and help regenerate a productive ryegrass dominated sward. Self-reseeding can be very effective on Italian (and possibly hybrid) rye grass swards.
Agri-environment grant payments may be available to compensate for any short-term losses in grass production.
