KEMERTON CONSERVATION TRUST

 'Conserving wildlife and ancient landscape'

 

Registered Charity Number: 702488 

 
WILD BIRD FEEDING TRIALS

(John Clarke)

Summary
Earlier research has already shown that providing winter foraging for farmland birds can be extremely effective.  This small, practical trial sought to demonstrate a simple way of supplementing or substituting winter feed by broadcasting seed into stubble or the remains of a crop. 

Observers discovered that the best ‘all-round’ supplementary feed was oats and that birds preferred to feed within 25m ( up to 50m) of a field margin comprising  a variety of cover types such as trimmed hedge, bushes and hedgerow trees. 

Where insufficient feeding cover was available the birds would not feed and where shelter from predators was limited they fed closest to available cover. 

A simple cover of long stubble or a the remains of a basic sown crop such as sweet corn or Fat Hen was sufficient for broadcasting supplementary feed. 

While this method is not suitable as part of a normal farm management scheme, nevertheless, at nature reserves or in situations where volunteers are available the cost is small but the benefits appear high.  The fact that the numbers of birds increased after the end of shooting season might mean that a) it may not be necessary to start supplementary feeding until the end of January and b) that former game cover strips could be utilised. 

Background
Changes in agricultural practices that have led to a reduction in food availability during winter are thought to have caused a decline in farmland birds.  A considerable amount of research has been carried out into the growing of wild bird cover strips and game cover, and much is already known about which birds prefer different seeds.  Modern agri-environmental schemes often include provision of cover and food for wild birds.  Therefore these small trials were not intended to duplicate earlier work but rather to look at how suitable habitat could be provided outside of such schemes – perhaps using voluntary labour where practical. 

Kemerton Nature Reserve in South Worcestershire is part of Kemerton Estate, a modern mixed farm.  Kemerton Conservation Trust advises the farm and manages several conservation sites there.  The reserve includes an area of ‘arable’ ground which is managed for arable wildflowers and in some years the farm shoot sows a strip of it as game cover.  The site is heavily grazed by rabbits and at times, geese.  The cover available (and therefore ‘natural food) varies greatly from year to year and so the plan was to broadcast seed into the cover at regular intervals throughout the winter.  The site is bordered on the north side by a trimmed hedge with some outgrown Hawthorn and a few standard trees.  A second side is bordered by rough grass into which scrub and Alder saplings are spreading.  The other two sides are open and adjacent to a rough grass area and a reed bed. 

The Trials 
During Winter 2003-4 Trust staff broadcast half a bucket of mixed wheat and rape seed over an area of rough stubble in the centre of the site.  This was repeated twice a week until feeding flocks dispersed in early Spring.  After the first few weeks the seed appeared to be attracting only Woodpigeon, Partridge and Pheasant.  It was not until the end of the shooting season that smaller birds began feeding there in numbers but seemingly reluctant to do so out in the middle of the site and so the feeding area was gradually moved closer to the boundary hedge.  Numbers and species of bird feeding there increased and it eventually became clear that the optimum feeding area was within 25 metres of the hedge – although Skylark and Meadow Pipit fed between 50 and 25 metres away. 

The feed ran out and so a neighbouring estate offered to help – this time, as a trial only oats was used.  The numbers of birds increased.  Peak numbers for species included 40 Reed Bunting, 20 Yellowhammer, 20 Dunnock, 25 Chaffinch, 15 Greenfinch, 20 Skylark and 6 Tree Sparrow.  This was the first record for Tree Sparrow on the estate for over ten years. 

During Winter 2004-5 the feeding site included an area that had been planted with sweet corn.  This time only oats was used for the supplementary feed and again small birds did not appear in good numbers until late January/early February.  It was again apparent that the birds preferred to feed within 50 metres of the hedge – with most occurring in the first 25 metres. 

Species recorded before an illness forced the staff member to abandon the trials for that year included Tree Sparrow, Reed Bunting, Chaffinch, Yellowhammer Linnet and Skylark. 

During Winter 2005-6  it was decided not to begin supplementary feeding until late January.  This time the feeding area was dominated by Fat Hen and a few birds had been feeding there but when staff began introducing oats numbers increased considerably.  There were fewer Yellowhammer and Greenfinch but counts of up to 40 Skylark, 50 Reed Bunting, 50 Chaffinch, 25 Linnet and 2 Tree Sparrow were recorded.  Small numbers of Dunnock were also seen. 

Elsewhere at Kemerton, a game strip attracted flocks of small birds.  The strip was on a headland adjacent to a fence and with a bushy Hawthorm hedge along both ends.  The birds appeared to concentrate on feeding within 25m (up to 50m) from each end. 

The neighbouring estate decided to carry out a similar trial and regularly spread oats into rough stubble (after forage turnips) in a headland adjacent to a grass track and an outgrown hedge.  It was not possible to carry out more than one count there (and then in bad weather) but 50 Yellowhammer, 20 Chaffinch, plus smaller numbers of Dunnock and Greenfinch – and two Tree Sparrow were present. 

In 2006 due to a lack of communication between the estate and Trust staff, half of the site (furthest from the hedge) was put into Set-aside and therefore was not sprayed off or planted.  The area adjacent to the hedge was cultivated and planted up with ‘game cover’.  However, this took place so late in the year that a combination of timing, drought and rabbit grazing destroyed the crop and by the winter only a close-cropped and very open sward remained.  The Set-aside area was dominated by basal rosettes of Ragwort and Teasel, leaving little bare ground and no cover for the birds.  During Winter 2006-7 Trust staff resumed supplementary feeding with oats but the only species recorded were Pheasant, Red-legged Partridge and Woodpigeon.  Despite regular counts throughout January and February no other species was recorded as feeding there. 

Observations and Conclusions
Small birds preferred to feed within 50 metres (better 25 metres) from the hedge, which was clearly providing shelter from the weather and from predators. 

It was noticeable that different species of bird tended to perch at the various heights available in the hedgerow.  For example, Chaffinch invariably flew up into the trees, whilst Reed Bunting and Dunnock favoured the low, trimmed areas.  Yellowhammer and Greenfinch utilised the larger shrubs.  While this was not a hard and fast rule it was clear that there were preferences. 

Numbers of small birds did not increase until late January/early February. Observations elsewhere on the estate showed that many birds were finding food at and around Pheasant feeders and in the reed beds. 

Oats appeared to be the best all-round food, seemingly attracting many species.  However, it is known that where it occurs ‘naturally’ in stubble fields this food source is rapidly used up.   

It would appear that where no agri-environmental scheme is available providing an artificial arable wild bird feeding area can attract large numbers.  By supplementing the basic feed the site can provide foraging until Spring. 

The feeding site should be chosen carefully – ie adjacent to good cover.  Small birds were reluctant to feed in areas of bare ground or with little or no cover. 

If necessary, the ground should be sprayed off prior to cultivation and then sown with a simple cover species such as Fat Hen.  Over the short period of these trials it was clear that the highest numbers of birds were attracted by a basic cover of Fat Hen, with broadcast oats as a supplementary feed. 

It is clear that when no stubble or basic cover crop was available the smaller birds would not feed. 

In this trial area it was preferable to broadcast feed twice a week – although it would probably be as effective if food was spread in greater quantities but once per week.