Two measures have been designed to benefit corncrakes. Early and Late Cover provides suitable tall vegetation throughout the breeding season, especially at the start and end of the season when grazed or cut vegetation in grass fields is too short for the birds.
Delayed mowing of hay or silage crops delays the date of mowing to reduce the overlap between the breeding and mowing seasons, and involves the adoption of corncrake-friendly mowing techniques to reduce the loss of chicks to mowing.
Why do Corncrakes Need Early Cover?
Corncrakes spend most of their lives in tall vegetation; or ‘cover’. Early cover is important for corncrakes returning from Africa, as there tends to be very little vegetation growth in the areas they return to by April/ May.
Corncrakes need cover to
• Hide from predators
• Hunt for food
• Nest and raise their young
• Attract them to an area when they are at the end of their migration
What this will achieve
The aim of this measure is to manage areas which will provide vegetation cover for the protection of Corncrakes, their eggs and fledglings, throughout the breeding season, in particular the early and late stages when available cover is scarce. Each calling male requires at least 0.1ha of good quality ELC habitat.
Early and late cover (ELC) maintenance and creation, when carried out adjacent to the nominated fields selected for Corncrake-friendly mown (CFM) or grazed grassland management, will provide cover for Corncrakes arriving back from wintering grounds in April and May and also will provide shelter late in the season when most of the surrounding grassland has been cut and/or grazed. This is because Corncrakes require vegetation which is at least 20cm (8 inches) high for the entire breeding season.
New early cover areas can be created during autumn/winter months or in early spring when Corncrakes are not present on their breeding grounds. Depending on local soil conditions and what type of tall vegetation is available locally, farmers should aim to create patches of tall vegetation, using the appropriate method below
How to Create Early Cover for Corncrakes
Soil nutrition and fertility is the most important aspect of early cover creation. The more nutrition is present at the beginning of the process, the longer the earlier in the year the plants will grow, the longer cover will thrive for, and the less work needs to be done to maintain it.
Place nutrition source (well-rotted manure or rotted silage bales are ideal).
Add appropriate plants/ seeds/ rhizomes or roots.
Fence when necessary to avoid grazing in the high summer (cover must be grazed after the end of September to ensure the areas do not become overgrown and rank).
Add nutrition to the cover area as needed (spreading some additional manure each year can ensure vigorous early growth, ideal for corncrakes).
Suited to dryer ground
Roots and rhizomes can be transplanted from other areas
Needs high levels of nutrition to thrive
How to: Dig up and collect rhizomes from existing areas. Mix the rhizomes with farmyard manure, ideally in at equal proportions by volume and spread the mixture over the site to a depth of approximately 15cm, but generally not less than 12 cm.
Suited to damp ground
Can transplant plants or rhizomes
How to: Dig up and collect iris from existing beds. Mix the iris rhizomes with farmyard manure, ideally in equal proportions by volume and spread the mixture over the site to a depth of approximately 15cm, but generally not less than 12 cm. To aid the establishment of the iris, the site should normally be in a damp condition for a significant proportion of the year.
Reed Canary Grass
Stands of reed canary grass can be created by transporting soil containing rhizomes riverbanks and other wet areas to prepared areas in autumn. This species does best in damp areas, but competition from grasses should be kept to a minimum.