Farm Ponds to Increase Wild Duck

New Zealand Journal of Agriculture, Volume 94, Issue 6, 15 June 1957, Page 596

Farm Ponds to Increase Wild Duck

THERE is increasing interest by farmers > in producing wild ducks both for sport and aesthetic reasons.. Reports from overseas show that wise farm management and game production are both possible on an efficient unit. This article by L. C. Bell, Field Supervisor, Wildlife Branch, Department of Internal Affairs, Wellington, discusses the results achieved by a Northland farmer, Mr. C. W. Kokich, of Kokopu, who is a pioneer of this movement in New Zealand.

THE valley of the Mangere Stream west of Whangarei is typical Northland farming country, with fertile flats bounded by poor hills. There are extensive swamps to the north and smaller ones to the south, with the , tidal reaches of Whangarei . Harbour to the south-east. The Kokopu district has thus been noted for . grey, duck, but in. recent years much of the swamp lands have been developed for farming. . . Mr. Kokich’s farm at Kokopu is of 400 acres. It was originally developed by his father, but the present owner has increased its production until today the larger part of the property is highly developed. Numerous shelter belts planted round the paddocks are a feature of the farm. A herd of 140 to 150 cows is milked and replacements for these are bred and carried on the property together with store cattle, a total of about 230 head of stock being carried yearly. Mr. . Kokich with an assistant manages the herd, calves, store cattle, and pigs. From 2000 to 3000 bales of hay are produced each season, while usually each season from - 200 to 350 tons of lime and fertilisers are spread by contractors. As he developed the farm Mr. Kokich decided that he would like to , have a place where he could see wild ■ ducks and shoot a few during the shooting season. Mr. Kokich believes that responsibility for maintaining duck numbers rests with the shooting land-owners, acclimatisation societies,

and shooters and that they must now realise that the days are about ended when any old thing will do for wildlife. The longer conservation measures are withheld the harder it will be to „ est fup decline in the erev duck D onulation * F . ' Mr. Kokich urges landowners to provide habitat conditions under which duck will increase. He states that the measures taken on his farm, details of which follow, have produced more than 1200 ducks in 10 years. Shooting has been restricted to an average of 17 ducks per gun each season for two guns. " ° ' r rs Siting of Dams . Kokich had little choice in I Mr KOkicn .had little choice in selecting dam sites, but fortunately on the Property there was a shallow gully « M To ‘the’Mangere Stream which provided sites for the first three dams.: The drainage area was limited ; and normally the stream does not carry a big volume of water, thus lessening the risk of wash-out through lack of balance between dam strength, size of : spillway, and maximum water flow. The gradual slopes of the land ensured that the floor pro-

file for each pond shelved gradually, This resulted in shallow ponds—a very important feature. . The fourth dam site was 500yds. away in rolling hills on the fringe of some scrub-covered, undeveloped gumland. In this less suitable terrain water depth is greater, except at the head of the pond, Pond No. 1 ... . Initially the site of Pond No. 1 was a small manuka-covered swamp with no open water situated in a corner of the farm. Most of the scrub was first cleared ■■ by hand to ultimate water level, but a certain amount was left standing out of the water to ..provide escape cover for the ducks from escape v^, for m ducks from hawks. , A small amount,pi raupo was eft JVscoo^rkokich in 947 “ft. =«• hi S h . with a ' width of 25ft. at ..the bottom tapering to : 15ft. at the top. This backed : up f acre of water of which most was less than 3ft. deep, - Before the dam. was closed a spillway was excavated on solid ground around the dam. Finally the dam was sown in grass and afterward top-

dressed three times, with a view to obtaining the best possible sole of grass for consolidation as soon as possible. This practice was followed in later. ponds, and the , dams now serve as . useful tractor crossings. . Natural plant cover on the banks of the pond was left. This was predominantly manuka with a few small totara and some undergrowth.

The pond, dam, and a fringing area were then made stock proof by some fencing which was additional to the existing boundary fences. ' As there were gaps in the natural growth, weeping willow, flax, oak trees, and Hakea saligna were planted in carefully selected areas.

. The cover plants put in have made rapid growth, owing to fertile soil and high rainfall. Without any planting many kinds of aquatic plants have become established, including types completely submerged, those partially submerged, and ones which grow on banks at the water’s edge. Among these are a . number of plants which provide ducks with food.

Grey ducks began using this pond immediately. It was shot over during that year’s shooting season and a limit bag was obtained on the first day. With the coming of spring five clutches of grey duck were reared and further

clutches have been reared each year since. Pond No. 2 The dam for Pond No. 2 was constructed by a bulldozer contractor in 1949 at the very head of the first pond. This earth dam is 12ft. high and 150 ft. long, being 30ft. thick at the bottom and tapering to 12ft. at the top. The earth was obtained from the excavation for the spillway leading to Pond No. 3, which was cut 6ft. deep and 10ft. wide at the bottom with sloping sides. The spoil was pushed directly into the swamp forming the dam and involved 25 hours’ bulldozing at £3 per hour. Present costs are much the same. An area of 1| acres of water was thus obtained with a considerable amount of shallow water under 3ft. deep along the edges and at the head. After excessive rainfall during a cloudburst in 1953 the dam gave way. It was rebuilt the following year with a much larger spillway cut on the solid through clay, and Mr. Kokich is confident that it is now large enough to cope with such downpours. Ducks began using the pond as soon as it was full. As well as grey duck it was pleasing that the rare brown duck

(commonly called brown or red teal) found it to their liking, and as many as 30 have been counted there at . one time. , During the first years, cover was provided by several clumps of native trees and shrubs already growing about the pond. In 1955 improvements were made by. fencing along . part. of one side of the pond and planting the types of plants already mentioned in the resultant enclosures. The banks of the pond on the other side are mostly in pasture and as they gradually shelve, they provide good sunny loafing spots for ducks as well as allowing stock to get to water. Pond No. 3 Pond No. 3 was constructed by bulldozer at the .same time as No. 2, the site being chosen so that its headwaters reached to the base of the dam of Pond No. 1. An earth filling 7ft. high, 90ft. long, and 22ft. wide at the bottom and 12ft. wide at the top holds back If acres of water, of which most is less than 3ft. deep. A short lengthof fence was erected to exclude cattle on one side of the pond, and the enclosed area planted with the same species as already mentioned. On the

other side of the pond there is ample opportunity for duck loafing spots and stock watering.

Pond No. 4

Pond No. 4 is in a back corner of the farm not yet developed from scrub. The scrub area is fenced off from the remainder of the farm and water for stock is piped from the dam through the fence to the adjacent paddock. Later, when the area is developed it is planned to retain a small area of scrub about the pond and ring fence it, still piping out water for stock as at present.

This. pond was also constructed in 1949, and the 15ft. high dam banks up s acre of water, of which much is 10ft. or more deep. Shallows are mainly restricted to the head. As the ground here is less fertile than on the flats, there is not such a lush growth of aquatic plants along either the edge or in the restricted shallows.

Cover

Wherever possible existing plant growth has been used to give cover for nesting, brooding, and general shelter and to provide escape cover from hawks for young birds. Where necessary trees were planted to a planned patternweeping willows just

in from the water’s edge at intervals to provide shade, brood cover, and escape cover, hakea behind and between the willows to reduce winds and draughts, and scattered oaks for general shelter, as acorns are a useful supplementary food for ducks. Clumps and rows of flax have, been put in at the back of the trees to supplement nesting cover. Weeping willows provide good cover and, unlike many other kinds of willow, do not spread aggressively over wet lands, However, because

they can overshadow much of a pond and reduce the amount of sunlight, which limits aquatic plant growth, some of them may have to be cut out when they become large. It is known from experience elsewhere that blankets of duck weed (Lemna and/or Spirodela) can cover water in ponds if they become too sheltered. Such close growth can cut off light from other aquatic plants and so some thinning of the shelter belts may be required. In suitable waters raupo can also become aggressive,

ousting useful aquatic plants and eventually leading to a pond silting up. This problem could be dealt with by controlled raising of water levels to drown out the raupo.

Loafing Places

Though cover is essential, Mr. Kokich realises that a dense jungle of vegetation right to the water’s edge and completely surrounding a pond is not desirable. Ducks like to be able to get on land at a gently shelving margin and sun themselves, preen their feathers, and sleep. Such a margin is not as important on an area used only at night for feeding, but is essential in daytime resting areas and adjacent to nesting cover.

Where cattle have free access to a pond they may, by trampling and eating, reduce the marginal vegetation to a point where few food and cover plants are left and the area is no longer attractive to waterfowl. A happy medium has been achieved on this farm by having part of the margin fenced and part available to stock. A portion of the margin thus provides food and cover and the remainder the open shore line which is equally important for waterfowl.

Food Plants

Aquatic plants readily established themselves on Pond No. 1 and in shallow waters in other ponds. Where stock were debarred from free access marginal plants soon grew up. Not a great deal is yet known about duck foods in New Zealand, but from work overseas and the little known here there is among aquatic and marginal plants a variety of food. Oak trees provide acorns, which are available for only a portion of the year, but ducks can and do range far and wide to obtain suitable foods during the various seasons of the year. Even the young can be, and are, moved by the

mothers to where food is available. However, from the number of young birds reared on the farm it is evident that food of the right kinds for young birds is available on and about the ponds.

Seeds of many plants are carried on the feet and feathers of ducks, so that conscious effort to establish a suitable range of aquatic plants is not necessary. Until the food plants which grow or can be grown on or near the margins of ponds are identified there is little point in planting for food.

A farmer should be exceedingly careful if he decides to introduce a plant for food. If he has any doubt about the value or growth habit of the species, he should seek the opinion of a field officer of the Wildlife Branch or of the Department of Agriculture. To introduce unwittingly a serious weed, such as water hyacinth, could be disastrous.

Predators

Unlike many sportsmen and farmers, Mr. Kokich has made no special effort to control predators. He has relied on the provision of suitable conditions for ducks to thrive. Investigations he has made showed that even pukeko, regarded by so many as a menace to ducks, did not adversely affect production .of grey ducks on his farm. From the study of some 30 nests Mr. Kokich found that the rat, not the pukeko, was the main predator.

Conclusion An. indication has been given of the production of grey ducks which has been obtained by suitable management of a few acres of farm land for waterfowl. Much money and effort have been spent throughout New Zealand on the establishment and attempted establishment of mallard ducks. However on this property, and it applies to a few others known, the owner has shown that native ducks can be increased if suitable attention is given to their requirements and that good farm management and wildlife production can work. together. To Mr. Kokich the aesthetic value far outweighs the money spent, but from the strictly practical viewpoint he has been rewarded in his good land management by the establishment of stable ponding areas which provide not only clean, cool water for stock, but assist in preventing soil erosion. The dams also provide useful points at which a tractor can cross a gully. Last, but not least, he is able to harvest a portion of the duck crop which his land produces.