National News> April 2008

For the Record.  (Or “I bet you didn’t know that about Canada geese”)
Graeme Hughes - Central South Island Fish & Game Officer

This article was originally published in Fish & Game Magazine, special game issue 26 and appears here by kind permission of Fairfax Holdings
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There has been much written in farming publications and in farming pages of daily newspapers about the crippling effect waterfowl can have on the land and the people that farm that land, such as, pasture depredation and fouling caused in the main, by Canada geese and to a lesser extent black swan and paradise shelduck.  It has been a common complaint that domestic stock will not graze where water fowl have been feeding due to the fouling of surrounding pasture.

For the record, studies have shown that domestic stock will graze amongst goose droppings if needed, despite observed preferences for non fouled forage.  Goose droppings lose their stock repellent effects within a day or two and cattle have been observed eating goose droppings.

Goose droppings provide nutrients to the soil. “Both geese and swans produce manure which is of value to the land, containing as it does, nitrogen, phosphates and potassium. Although the amounts are relatively small, nitrogen 2.2%;  phosphate 1.0%; potassium 2.0% by weight, the passage of food is so rapid that much of the conversion of grain for instance, to manure takes place while the goose is on the field.” [Dr Janet Kear, Wildfowl Trust, United Kingdom.1963.]

Documented agricultural benefits of geese include the reducing of weeds, plant pests and plant diseases (e.g. by feeding on seeds and crop residues), and the accelerated turnover of organic matter and nutrients (e.g. nitrogen, phosphorus and potassium). Hence one way or another, geese may stimulate plant growth rates. [“Canada Geese in New Zealand” E.G. White, Centre for Resource Management, University of Canterbury & Lincoln College, 1986.]
 

While the research is becoming aged, I don’t think much will have changed. Today, geese and swans still eat grass, green feed and grain just like they did back then.  The main difference is that there is a lot more of it available now thanks to land-use intensification and development.

Food intake
There have been some bizarre statements published on the amount of food a Canada goose will eat. There are 12 subspecies of Canada goose, ranging from the diminutive Cackling Canada goose (Branta canadensis minima) to the giant Canada goose (Branta canadensis maxima). In New Zealand a male Canada goose in prime winter condition may attain a weight of 5.2kg, a female 4.5kg.  Farmers have in several publicised articles claimed that one goose will eat as much as 1 or even 2 sheep, (there have been higher ratios stated of as much as 4 or 5 sheep!).

For the record, the biggest flying bird on the planet is the condor with a 3.2 metre (10 foot) wingspan weighing in at 12kg. If a goose were to eat as much as some farmers claim, it would have to weigh about 25kg! The true picture is of course the other way round. Research on goose grazing on Lake Grasmere station show the farmer “guestimates” are quite incorrect.

For the record, 4 or 5 geese = 1 stock unit (1 x 55kg ewe)
  35 geese  = 1 dairy cow (1x dairy cow = 7 stock units)

The best estimate for New Zealand Canada goose food intake (from E.G. White, 1986) is 0.3 – 0.4kg dry weight per bird per day (6% - 8% of body live weight).  The goose digestive system, unlike that of most other herbivores, is incapable of digesting fibre. With a limited breakdown of plant cell walls, food passage is rapid resulting in a goose producing 160 droppings per day. Dry weight of each dropping is 0.0019kg and dry weight of droppings per goose per day = 0.30kg. (Inefficient goose digestion means less forage is eaten than might be inferred by numbers of droppings.)

Canada Geese require less than half, maybe one third the food of sheep to produce a dropping of equal volume. (Based on 0.7:1.0 bulk densities of goose: sheep droppings from grazed pasture, and matching grass digestibility of 30:70%).  [“Canada Geese in New Zealand” E.G. White, Centre for Resource Management, University of Canterbury & Lincoln College, 1986]

Canada Geese have been blamed for poor water quality. Compared with much larger herbivores the goose hardly deserves a mention.

For the record, in a recent New Zealand publication, researchers claim that in their study of water quality downstream of a river crossing used by 246 dairy cows, the cows were about 50 times more likely to defecate in the river (ford) than elsewhere on the access race. On another NZ study, 60 times more likely.  Five faecal deposits (“cow pats”) weighed any where from 0.6kg to 1.4kg and had an average weight of 0.92kg and an E. coli content averaging 12 million colony forming units (cfu) per g of wet weight.  Average E. coli content of the deposits was 9 billion cfu’s.

If there were two milkings a day the researchers calculated that 447 billion cfu of E.coli x 2, mobilised per day by the four crossings, mixed into the daily water flow at 1.09 cumecs corresponds to an average concentration of 950 cfu / 100 ml (more than 100 times the guidelines for contact recreation), increased suspended solids by about 54%, reduced visual water clarity by about 11% and increased total nitrogen by about 10%. [“Water Quality Impact of Cows Crossing an Agricultural Stream, The Sherry River, New Zealand”.  Rob Davies-Colley, NIWA; John Nagels, NIWA; Rob Smith, Tasman District Council; Roger Young, Cawthron Institute; Chris Phillips, LandCare Research.]

Most people know the difference between a 5kg Canada goose and a 450kg dairy cow and will understand there will be significant difference in food intake and egestion between the two. The herd of 246 cows monitored at a river crossing equates to 8610 geese in terms of food intake. 1 cow = 35 geese. (In the milk business 246 cows is not a huge herd today)

For the record, I know which of the two species I would prefer in my swimming pool, if I had one.

Table quality
The Canada goose in the northern hemisphere has been valued as a prestigious game bird and an excellent table bird for centuries. I am unaware of any game bird which is not considered as fine table fare; it is one of several criteria which designates a species as a game bird.

In New Zealand the species has been established and hunted for a much shorter period but has always been highly valued and much sought after especially for its eating quality. Any person who enjoys game meats will find Canada goose is no different. It is not strong flavoured nor is it greasy or fatty.

However, persons who have been provided with “grey geese”, either domestic or feral, have found they can be strong to taste and are definitely “fatty”. They assume incorrectly that “Canadas” taste the same. I was recently informed of a televised programme which showed Canada goose breasts being tossed onto a barbeque plate and when these were supposedly “done” fed to guests who were less than enthusiastic with the quality. 
Any waterfowl hunter would not be surprised at the result and the recipe and method was designed to fail; it was that kind of programme. The age of the bird, the time of year and how it was prepared and cooked and how it was stored prior to cooking are all important if the end product is to be enjoyed. Geese in the moult are in very poor condition; geese incubating eggs are down in condition. Geese shot early in the special season, just after the moult are never as good as birds shot later in the year. Geese can live for 27 years. While most shot are a lot younger one should obviously choose younger birds for prime table quality. You wouldn’t consider eating mutton or beef that age so why should game bird meat be any different?

There are several quick and easy ways to identify a goose that will be suitable for the table. Choose smaller birds. Choose birds with indistinct “smoky” plumage colouration, cheek patches that are “smudgy” and less defined and compare with other birds you have shot. These are younger birds.

Large and heavy geese, with clean, distinctive coloured plumage, prominent bare knobs on the leading edge of the first wing joint indicate age and require slower cooking. There are other tests, such as checking the elasticity of the wind pipe and the strength of the upper bill and looking at the feathers; however the former quick tests are usually a reasonable gauge of age. “Breasting” birds is quick and the meat can be cooked in a variety of ways, however, a whole bird oven roasted is the food of kings.

For the record, never throw fresh goose breasts on a barbeque plate!

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