Grass is the basic diet for both wild and domesticated geese. The wild birds have greater choice of plant species, and can migrate to follow the growing season for the best bite, but their farm cousins are confined to the same patch. So it is essential, for the health of the domesticated birds, that their pasture is well managed and they have supplementary food.

Not only do healthy geese need grass in their diet, but there will be no profit if commercial geese are reared solely from bags, for they can soon eat more than they are actually worth. Pasture for rearing and maintenance is needed to make any profit from geese for the Christmas market because they will then be up to 30 weeks old, in contrast to the grain and soya-fed broiler chickens of just six weeks of age. So, now is the time to think of managing grass quality for the breeding birds in 2010 and ensuring that clean grass is available for the goslings in spring.

Wild geese Species of wild geese show a lot of variation in the size and shape of their bill, because of adaptation to the varying foods they eat. The wild swan goose has a large, long, heavy bill which is not suited to short pecks at a tight sward.

The lamellae at the side of the bill, developed for cutting action, are not as well developed as in the greylag. So the swan goose chooses larger-leafed vegetation and roots. Even the domesticated breeds developed from the swan goose – the Chinese and African – have slightly differing feeding habits from the greylag derivatives.

Many species have an “all-purpose” bill which can be used for grubbing out roots, grazing pasture or stripping seeds from grasses. But some of the smaller geese such as the Red-breasted and Lesser White-front are more specialised. They have short beaks for precision pecking, and they like short sward. Peck rates have been recorded at up to 180 per minute!

The habitat and diet of wild geese, especially within Europe, has probably changed over the centuries as more and more land had been cleared from forest, marsh and fen.

Glasswort mudflats, tidal saltmarsh grasses, and fen vegetation may have been more important before the marshland habitat was drained and agricultural grassland became more widely available. As the grazing farm animals maintained a good turf, so the geese moved onto this agricultural land.

Farmers’ winter ryegrass and wheat are crops prized by geese which descend in October and stay until April. Thus management of crop land, and even compensation payments, may take place where goose conservation and farm livelihood are in conflict.

The actual distribution of geese has probably remained the same, because they are conservative in their habits. They choose traditional places of safety overnight on estuarine sandbanks or inland lakes where the density of the birds in the flock is very high. Depending on the species, these flocks will fly out to do most of their feeding within two to five kilometres of the overnight roost.

Geese are very inefficient feeders. They cannot make use of the cellulose in the same way as cattle and sheep. They need to gather food over a large part of the day. Even in winter, when daylight hours are short, they have to spend seven to eight hours eating. This short grazing time is the reason why birds need to put on as much weight as possible during the autumn in order to reach a peak weight in November.

The energy reserves they build up will get them through the harsh winter months, on poor-quality resources, before new high-nutrient vegetation growth starts again in spring.

As the growing season for grass starts again in the southern over-wintering regions, geese first take advantage of this new green bite then leave, sometimes using staging posts before reaching the breeding grounds. For example, Barnacle geese at Caerlaverock leave the Solway from mid April onwards and may use locations off Norway and southern Spitzbergen before reaching the nesting sites on Bear Island, Svalbard, 14-31 days later at the end of May. Wild geese therefore utilise the onset of the growing season that changes with latitude. As they migrate from their winter roosting locations back to their nesting sites further north, they get a sequence of “first bites” where the shoots of grass offer top protein value, at several locations.

They are building up protein and nutrient reserves essential for the production of high quality eggs. In contrast, on their return journey to the Solway in September/October, the flight can be made in as little as 48 hours when there is clearly no advantage in staging the food supply.

What sort of grass?

On the farm, there is mainly grass rather than a menu of saltmarsh, fen and moorland plants. But there are different varieties of grass and herbs to choose. In one study of wild geese, grass including some clover is the principal food in spring during the pre-breeding period. My own geese don’t particularly like clover, but others might, so do watch the behaviour of yours to see what they prefer. Up to 30 per cent clover improves nutrient status (nitrogen). If grass is to be reseeded, then it is worth talking to a local seed merchant to see what they have in stock and what they recommend, because protein content varies according to the species, peaking at 30 per cent in optimum conditions. My local merchant recommends a “mid late mix” of varieties of rye grass with Timothy, generally used for a long-term ley. With cutting and grazing, it produces a tight, dense sward. Timothy is cited as having lower protein content than other grasses, and rye grass as having higher digestability. Rye grass alone can result in some bare ground around each plant, so lower growing grasses with creeping stems cover the ground better. However, rye grass is successful if kept closely grazed or mown.

Grass quality Where different qualities of grass are on offer, geese will choose darker-coloured, fertilised, short-length pieces. Short, fertilised grass is preferred to coarse, low-nutrient grass, and it seems to be recognised by the “pull actor”. If a tug at the grass yields a mouthful easily, the grass is desirable and palatable.

The behaviour of domesticated geese also shows that the birds choose areas of short, clean grass visually and well as by touch and taste. If a new area of sweet grass is opened, the geese will visit, inspect and talk about it before eating and confirming the condition, flavour and feel by the tug. Tips of short shoots are chosen over longer pieces.

Once a good patch of grass is found, the geese will repeatedly graze at this small patch to keep it short whilst adjacent areas may run to long, tough grass which is not suitable for them. They are mimicking the behaviour of wild geese during the flightless period when they are moulting and also rearing goslings.

Greylag geese have been recorded as re-grazing sward at intervals of between six-eight days. This was less that the experimentally determined optimum interval of nine days or more which would give most biomass and protein accumulation.

Clearly, geese like baby vegetables too; they are demanding the high protein content of the fresh sward at the time when they are also growing new feathers. The implication, from the wild goose feeding habits and observation of domesticated geese, is that grass must be kept short to maximise its food value.

Thus if larger animals are used to graze pasture with geese – and mixed stocking also gives better parasite control – then low biters such as sheep and horses are useful. If the larger animals precede the geese and the grass is allowed to regenerate for a week or so, then the goslings get the new shoots.

Do beware of mixing young birds with larger stock which can trample them, especially young lambs playing around.

Goose droppings from birds on pasture are very frequent, but they only become a problem if the birds congregate at one place. Droppings are just macerated grass, and far less smelly than sheep or cattle droppings. They rapidly disappear in wet weather and do not foul the land as much as is commonly supposed.

Geese cannot be used to get long grass into good condition. Any long grass must be removed first; so control of grass growth by mowing or sheep grazing is therefore essential to keep the shoots in good condition. Thereafter, geese improve grass.

Maintaining grass Grass quality is improved by maintaining a pH of around 6 - 6.5. If pH measuring equipment is not available then, as a rule of thumb, liming will be useful in the higher rainfall areas of the UK where the bedrock is not limestone. In Mid Wales, for example, pasture pH levels are commonly 5.5 or less unless the land limed.

Where pH is very low (acid), greater amounts of lime will be need to raise the pH to 6.5. Bags of hydrated lime (slaked lime) are available from agricultural suppliers.

The correct rate can only be applied if the pH is measured using a soil test kit (available for garden centres) and the soil type allowed for. For example, for clay soil at pH 5.5, 350g (11oz) is recommended for gardens to raise the ph to 6.5.

Take care to apply the fine, dusty hydrated lime on a day when wind speeds are low, and wear protective glasses and gloves because the dust is an irritant.

Lime is best applied to the garden in the autumn when it can be dug in. But lime has the additional benefit of destroying harmful bacteria so it can be applied to the grass surface prior to gosling grazing in spring, or to help clean pasture which has become dirty and is being rested. I just apply it as a fine dusting, spread from the garden shovel.

Once well watered by rain, the dust is safe; it is no longer an irritant. If a longer-term solution is required, calcified seaweed gives a longer, slower release of nutrients and the geese and poultry will enjoy nibbling the particles.

Parasite control Where geese are reared mainly on grass, then a knowledge of parasites and diseases is essential. Coccidiosis is a problem when pasture becomes dirty. Goslings especially will suffer and even die from high infection rates of this protozoan, and they will die from gizzard worm infestation.

So, find out about the lifecycle of these parasites to avoid problems. Practise rotation of pasture, or extensive grazing with mixed stock when the birds are old enough to free range. Worm accompanying adult birds so that they do not infect youngsters, and always start goslings off on clean ground.

Note that intensively reared geese and ducks should not generally suffer from these problems. However, their main food supply is from pellets and wheat which makes them much more expensive to keep than grass–reared stock.

Finally, remember that geese are not ruminants. They must have grit to puncture the grass in the gizzard so that the juices can be released. Make sure that both mixed poultry grit and coarse builder’s sand or sharp sand are available. Then the problem of crop binding will be avoided, and the geese will also grow better on their available food supply.

Key points Wild geese have a varied diet and select different plant species according to seasonal nutrient supply.

Young shoots of grass provide more protein than longer grass.

Protein demand is high in spring for producing viable eggs.

Adults in moult and growing goslings, also growing feathers, need high protein food.

Autumn and winter food can also include root vegetables and stubbles.

Grass quality should be maintained by liming.

Parasite build up should be controlled by regular worming and/or rotation of stock.

Geese and goslings need grit for the gizzard.