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HELPING YOU TO HELP WILDLIFE ON YOUR FARM |
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Late Cut Grass for Corn Buntings |
01.11.2005 |
Author: John Moir
Farm: Cairness Home Farm, Aberdeenshire. |
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Aims:
Since 2005, RSPB have been working with farmers to trial a late cut grass option for corn buntings in north-east Scotland. This began in response to finding that many first nesting attempts in grass silage were destroyed during mowing.
Corn buntings have undergone a substantial population decline and range contraction within Scotland and the rest of the UK during the 20th century, and particularly during the last 30 years. A recently published study in east Scotland reported an 83% population decline on 30 sites between 1989 and 2007. As few as 800 territorial males may remain in Scotland. Poor productivity through nest destruction is likely to have contributed to this decline. |
Management:
This trial work on late cut grass began with John Moir, a local farmer who was keen to explore whether some manipulation of his grassland management to benefit corn bunting could be compatible with his commercial farming interests. The Moirs farm 668ha of land on the northeast coast of Scotland in Aberdeenshire, running a herd of Aberdeen Angus, Scotch mule ewes and growing spring and winter cereals. Since 2006, some fields have gone into organic management. The decision to go organic was made in order to become more self-sufficient in feed and cut costs.
On the dry, sandy soil, the flush of spring grass growth usually occurs during late May/early June, coinciding with the onset of corn bunting breeding. Typical grassland management involved either one cut (during early July) or two cuts (during mid June and late August). Under the trial, some of the grassland was left uncut or grazed between early May and mid July/August (depending on nesting activity) and cut for hay, haylage or silage (depending on weather). Through the winter and early spring, fields are grazed tightly by sheep and pink footed geese. The late cut grass option was targeted at some of the less productive fields with breeding corn bunting and some of the organic fields sown with fertility boosting mixes rich in clover. Some of the latter are pulverised and prepared as compost as part of long-term planning to reduce erosion on light soils, and to enrich phosphate and potassium levels in these fields.
Where nests were located in fields that had not been selected for the late cut option, large areas were sometimes left standing around nests until chicks had fledged. This alternative sometimes resulted in successful fledging of nestlings, but on occasions where birds were at the egg stage, nests failed. Reasons for failure are not known but could be due to disturbance caused by cutting operations or predation. ‘Islands’ of uncut grass in an otherwise mown field may be more obvious to predators. This alternative requires a great deal of intensive monitoring to advise where the nest is located and thus, what area of grass to leave uncut.
RSPB advisors have worked closely with John on providing feedback regarding impact on breeding corn buntings and Scottish Agricultural College staff advised on the agronomic side of the option. The trial was originally a pilot project funded by RSPB and SNH and has since been introduced into Rural Development Contracts.
Under the trial, the economic cost of carrying out later mowing was calculated at £260/ha, but the payment was reduced to £224/ha in the scheme, reducing its economic viability on some areas of land. Ideally, payment rate should increase or, failing this, the cutting date should be brought forward to a point that still saves most nests but the quality of crop is better. The option would also be more practical if it could be moved around as part of a rotation. |
Achievements:
Across all participating farms involved in this project work, RSPB have found that by delaying grass cutting until late July or early August, corn buntings are five times more likely to fledge broods when compared to birds nesting in conventionally managed silage. On John’s land, numbers of singing males have increased from five in 2006 to 14 in 2008. This may well be down to delayed grass cutting and a suite of other sympathetic management, associated with organic systems and agri-environmental schemes. |
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| Images ©RSPB, except Greater Horseshoe Bat ©Bat Conservation Trust |
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