We have very carefully counted the number of birds breeding at Hope Farm over the last four years. We are delighted to have seen a steady rise in the birds of the arable farmland including skylarks, linnets, yellowhammers and reed buntings. These birds are the ones that have undergone such a catastrophic decline in the last 30 years.
We have also noted a rise in the diversity of bird species making use of Hope Farm in the winter. In our first full winter (2000/01) we had 57 species making use of the land. This number has risen steadily each winter and 68 species made use of the land last winter (2003/04). Much of this rise has been due to birds that had just been seen flying over, such as lapwings, golden plovers and gulls, now landing and feeding on the fields.
This winter we achieved a landmark in the number of bird species seen at Hope Farm when a barn owl was seen hunting at dusk over the stubble fields. This was the 100th species to be seen at the farm.
If we group together the number of territories of the farmland birds for each breeding season, as we have done in the graph, we can compare our achievements at Hope Farm with what is happening across the countryside. The comparable figures for Eastern England do not show the marked rise that we have noted although thankfully the decline seems to have been stemmed across the region.
The Government has set a target of reversing the decline in farmland birds by 2020. We have not just reversed it at Hope Farm, we have produced a major increase over the last four summers. Our aim now is to enable farmers to carry out similar management to that at Hope Farm with the result that they can reverse any declines that have occurred on their farms.
Overview harvest '03 - Ups and downs of crops and cash
The weather hit our crops last year with a dry spring and summer significantly reducing the yields of the wheat - they were down between a half and one and a half tonnes per hectare, dependent on the field and the crop's position in the rotation.
Whilst we lost on yield, we gained significantly this year on income, with a sharp rise in the world price of wheat. Comparable quality grain from harvest 2002 was selling at £55/tonne, this winter the wheat harvested in 2003 sold at over £90/tonne. Oilseed rape yields and prices were similar between the two years.
The wheat price rise, that was both unexpected and completely outside of our control, resulted in the highest income after costs in all the years that the RSPB has owned Hope Farm. After taking out crop production costs, income was up over £20,000 on last year.
Winter '03-'04 - Stubbles, seed and feed
Detailed research by the RSPB over the years has identified how the stubble left in fields after cereal crops have been harvested can sometimes provide rich pickings for seed-eating birds. They are able to search for and find cereal grains that were left by the combine harvester, and the seeds of weeds that grew within the crop or after it was harvested. When the stubble remains throughout the winter it can provide a vital source of food to enable birds to survive cold weather.
RSPB researchers have noted how some stubble fields support many birds but some support few. This appears to be due to a combination of the number and type of seeds present, how easy it is to find the seeds amongst the dead cereal stalks and how much time the birds need to spend on the look out for potential predators.
To untangle these factors and to help develop some practical advice to farmers we created different feeding conditions in two stubble fields. In half of each field the stubble was cut short in late autumn and then, creating a chequer board pattern, wheat grains were spread across half of the long and short stubble in each field in December, February and March.
Throughout the winter and early spring we kept a close watch on the birds using these two fields, noting exactly where they were feeding. We have now analysed the counts. The skylarks and game birds, including up to five grey partridges, preferred the longer stubble. Fieldfares and starlings preferred to probe for insects and worms amongst the shorter stubble and rooks rapidly learnt to go where the grain had been spread. Unfortunately, there were just not enough yellowhammers and chaffinches around this winter to come to any conclusions on how the length of the stubble affected them.
Early spring '04 - The cropping cycle
The oilseed rape in three fields failed to grow due to the very dry autumn and was resown with beans in the autumn. We had nursed the remaining, largest oilseed rape field through the late autumn and into the winter. We hoped that it would survive to pick up in the spring to provide a crop to reward our efforts.
Cold winds and heavy frosts in January and February put paid to any hope that the small plants would survive - the frost lifted them out of the ground and killed their roots. So, this spring, we had to resow with field beans. The seedbed was already prepared for the oilseed rape and the beans could be drilled into the ground as the soil dried in March.
Over the next three weeks the rooks first gorged on any seed that had not been buried deep enough. Then they feasted on the delicacy of bean sprouts as the young plants emerged up through the ground. However, we had expected some losses to rooks and had compensated for this with some extra seed. The loss we experienced was more of a thinning rather than complete removal of the crop in any area.
The early planted wheat that had been sown into such a dry soil in the autumn was still trying to make up for lost growth through into March. The later planted wheat had been sown into a better seedbed in October and received rain soon after, leading to a vigorous and even emergence. This later planted wheat looked in better shape than the early wheat throughout the winter and into early spring. This was the reverse of what might be expected in a 'normal' year.
Spring '04 - Butterflies on the edge
Many conservation bodies promote the planting of areas for wildlife using locally sourced seed. Most farmers will source their seed for sowing areas such as field margins from their usual crop seed supplier. The result is that they are likely to receive seed of varieties that have been improved for agricultural use by selective breeding and/or using stock from other European countries.
There is a risk that such varieties may be of reduced value for wildlife. They are certainly cheaper than seed from native stock.
Some experiments at Writtle College, Essex, have shown that the caterpillars of brown and skipper butterflies develop poorly on the agricultural improved varieties of their normal grass foodplant. Since caterpillars are an important food for the chicks of several farmland birds, such as yellowhammers, it is important to know if this holds true on farms.
Working with Writtle College and NIAB, a specialist plant breeding research organisation, we have sown a series of field margins with grass and flower mixes from different sources. Over the next three years we will be looking together at the use made of these margins by butterflies and how it relates to the varieties sown. This will help us to justify recommending the use of more expensive native varieties to farmers because of the added wildlife value. This work also has the backing of Butterfly Conservation.
Spring '04 - Early breeding season prospects
We counted up to 23 singing skylarks early this spring. This was higher than the same period last year, giving us hope that we may see another year of rising skylark numbers. We believe that we have provided very good conditions for them with undrilled patches in the wheat fields, areas of fallow on our set-aside and beans rather than oilseed rape as our break crop.
Egg-laying by the larks appears to be late though, probably due to several wet periods in April. This means that the late season nesting opportunities that we provide become all the more important in enabling each pair of skylarks to produce several broods of young through to harvest.