Recently a guest article was published on "Moose in Manitoba" with videos made in 2018 by Doc Moose, biologist, Dr. Vince Crichton. Today's guest article is the transcript of an article written in the 1980's by Ken Child, Wildlife Biologist entitled "Why Shoot Cow Moose" regarding the status of moose populations at that time in British Columbia. The article though written three decades ago is prophetic of what has happened in many parts of British Columbia today.
"Why does the Fish and Wildlife Branch continue to permit cow moose (antlerless) hunts?" is probably one of the most heard, voiced and argued questions amongst hunters, non-hunters and biologists alike. The question indeed is a many-faceted one which requires an insight into the subject of wildlife biology and a discussion of the principles of game management. The traditional antlerless hunts are confusing to the layman who believes that by killing cow moose, hunts are removing the breeding stock and in the long term decreasing the overall numbers in the herd. Consequently, most critics of antlerless hunts sincerely believe that such hunts can lead to nothing but harm. In this article, we hope to show these hunts, managed properly, are not only beneficial to moose populations in the long term, but necessary if the Ministry of Environment is to fulfill its appointed duties of "ensuring that, within the constraints of land capability and biological limits of each species, wildlife (moose) is available in sufficient abundance to meet the recreational and economic needs of society."
The Moose Herd
Consider for the moment a moose herd that is located in a wild, inaccessible area which is soon to be opened to development and resulting recreational demands (hunting, fishing, etc.) Although moose naturally show fluctuations in numbers over a period of years, we will assume this herd to be at a fairly dense level of population and has good numbers of older prime breeding bulls as well as mature productive cows. In this naturally controlled population, the sex ratio will vary between one male to every female (1:1) to one male to every two females (1:2). The rate of dying will also vary by age. About 50 percent of the calves (young-of-the-year) will die within the first twelve (12) months of life. As the population stabilizes, the remaining 50 percent or surplus will die at the following rates in the population: 25 to 30 percent in the 1 to 4 year old age classes, 7 to 10 percent in the 5 to 10 year old age classes, and the remaining percentage of the surplus in the more senior age classes (older than 10 years).
Prime Bull Moose
Having a good supply of these older prime males, the herd should be good for trophy hunting . . . at least for a few years until heavy hunting pressures have removed the older large-antlered (trophy) bulls. As the area becomes more accessible (road improvement or more constructions) and the hunting pressure increases, it does not take long (3 to 4 years) before the hunters have harvested most of the older prime males and increasingly harvest the younger two, three and four year old males. As the hunting pressure continues over the next few years, the male segment of the population will be composed primarily of younger-aged bulls, and these too will be heavily hunted each season. As the bull segment becomes younger in age, the hunter usually experiences poorer success for his efforts to take a moose and his recreational opportunities continue to become increasingly limited. Not surprisingly, both the hunter and non-hunter realize something is wrong and corrective measures are soon in demand. Regulation changes may follow thereafter. Following traditional lines, such regulations usually favored more restricted use of the antlerless (cows and calves) segment of the population. Unfortunately, such restrictions - furthered the exploitive pressures on the male segment of the population and promised to compound the problem rather than correct it.
The once "trophy" moose herd is now a socially imbalanced herd characterized by a distorted sex ratio, long lasting rutting season and calving period because the one to three year old males cannot breed all cows in their first and second estrous, a relatively young male segment and lowered production
Over Harvesting Bulls. What Happened?
All of the mature large-antlered bulls have been largely over-harvested,except possibly for a few that have escaped the hunt and those yearlings that were born into the herd the previous spring. Hunters are expert at observing the symptoms that something is wrong. A hunter will look over many cows, many without calf, in a single morning without sighting a bull! Something is wrong, and harvest strategy changes are warranted. But what happened? Hunting pressures, governed by traditional regulations, has distorted the bull:cow ratio, where certain age-classes of males (the prime breeders) have been over-harvested. The female segment, on the other hand, because of restricted or non-use (in antlerless closure areas) is of stable age class structure as compared to bulls. As a consequence, this social imbalance leads to population stress that is manifested in lower production (more "dry" cows), asynchronous rut (later in season), and poor survival of late born calves, that in concert, mean population decline.
How Can the Situation be Corrected?
The best thing that a manager can do for this moose herd would be to introduce a harvest strategy that would:
(a) be more protective of the prime breeding bulls and cows,
(b) improve the survival of calves,
(c) reduce the over-winter losses of calves to natural predators or winter conditions,
(d) improve reproduction, and
(e) adjust the age structures of males and females in order to maintain a high percentage of middle-aged cows and bulls in the population
Understandably, traditional antlerless sentiments have not and will not provide these management objectives. Rather than single-sex orientation, a harvest strategy must be designed that addresses maintenance of her integrity since a socially well-balanced herd is characterized by a high proption of middle-ages cows, a good supply of prime breeding bulls, and high calf yields. This her, when managed, will provide the hunting and non-hunting public optimal use and benefits.
Managing Moose Herds
In order to achieve these management objectives, management strategies must therefore address the need to protect the breeding stock and direct human use on the non-breeding and more socially immature male and female segments of the population. It is therefore necessary to exert high hunting pressure on yearlings (males and females) and moderate pressures only on mature females (cows). By such harvesting practices, most of the females in the population will be in the best reproductive age category (4 to 9 years). With more productive cows in the population, and social balance restored, population increases can be expected.
Managing moose herds for optimum sustained harvests is best accomplished by having more vigorous animals (of medium age 4 to 9 years) comprise the majority of the population. This mix of animals in the herd should maintain a proper social balance thereby ensuring good production. Although older cows do produce calves until they die of old age, the calves they produce are less likely to survive than those from a younger female because of low milk production and thus poor nutrition of the calf. Old cows produce fewer twins also. The hunt of cow moose, under some controlled program or strategy is necessary then to maintain optimal breeding and social conditions in a managed herd of moose."
To be continued ...
Links & References:
- K.N. Child 1981. Why Shoot Cow Moose? B.C. Ministry of Environment, Prince George, BC. Multilith.
- Further Reading: John Spicer "Biodiversity Beginners Guide" Oneworld 2006
Sustainability - buzzword for the 21st century
"Sustainable development is all about reconciling economic development with enviromental protection. It's meeting the needs of the present, with an eye on protecting our natural heritage for our children and their children."
~ John Spicer "Biodiversity"