From: robinson@ac.dal.ca
Newsgroups: talk.politics.animals
Subject: Re: Case Example #1
Date: 6 Apr 92 17:02:03 GMT
Organization: Dalhousie University, Halifax, Nova Scotia, Canada

In article <altar.702077093@sfu.ca>, altar@beaufort.sfu.ca (Ted Wayn Altar) writes:
>  
> It has frequently be stated that hunting is necessary to keep
> the deer populations controlled.  Well, here is one carefully
> documented case example of how such "controls" may work.
> Of course, this is only one example, but it is disturbing
> and makes the point that any generality about, and appeals
> for, "control" does need to be more critically assessed.

Depends on what you mean by controlling the population.  I don't think 
anyone here has stated that left unchecked deer will multiply infintely.  
Rather, they will multiply until they overgraze their range.  That range 
will then be capable of supporting far fewer deer than it once did (over 
grazing seriously damages habitat) and there will be a large winter die 
off.  Lots of deer will starve.  Naturally, during this time of intense 
competition for food, all animals will be weakened to one extent or another 
and the possibilities for introducting disease into the population 
escalates.

>  
> During the 1970's "resource managers" instigated deer hunting at
> the Great Swamp National Wildlife Refuge supposedly in order to
> pander to some complaints that the deer were destroying seedings
> adjacent to the refuge and that "overbrowsing" had made for the
> disappearance of indigenous short-eared and saw-whet owls from
> the refuge.  Since 1974 deer hunting has been permitted, one deer
> or either sex per hunter.

Since they were doing this 'in order to pander to some complaints' it isn't 
hard to see that the author discounts the problems of overgrazing.  
Nonetheless, they are real.  Such overgrazing could have a very serious 
effect on both the seedlings and owls.

>  
> Below is a case example of the effects regulated hunting on the
> deer populations of the Great Swamp National Wildlife Refuge in
> New Jersey.  These results were tabulated by the U.S. fish &
> Wildlife Service.
>  
> Deer Pop. at the Great Swamp National Wildlife Refuge
>  
> Year     approx.   # of deer  % of     approx.  days of     # of
>         prehunt    killed     herd   posthunt  hunting     daily
>          pop                killed    pop.                hunters
> ------|--------|-----------|-------|---------|---------|--------
> 1969      520     NO HUNT
> 1970      600     NO HUNT
> 1971      650     NO HUNT
> 1972      650     NO HUNT
> 1973      520     NO HUNT
> 1974      570     127        22%      443         6       150
> 1975      456     106        23%      350         6       150
> 1976      385     128        33%      257         6       150
> 1977      375     106        28%      269         6       150
> 1978      500     104        21%      396         6       150
> 1979      600     178        30%      422        10       250
> 1980      650     149        23%      501        10       250
> 1981      600     150        25%      450         8       250
>  
>  
> Now, what can we conclude from an inspection of the above chart?
>  
>  
> 1.  The maximum # of deer supportable at this refuge is approx.
> 650

No.  We can not conclude that.  We can conclude that the maximum number 
that have ever been on the land was 650 from when it first started to be 
measured.  The numbers indicate that from '69 - '73 the population went in 
a wave whose peak was 650 critters.  Don't forget that these population 
figures include new fawns.  For such a small increase in the population, 
there had to be a fairly large die off from starvation.  As Tim has already 
pointed out, it is this die off that determines the number of deer the land 
can comfortably carry.  From these numbers it would appear to be between 
three and four hundred animals.

>  
> 2.  Habitat was probably in good shape just before the hunt as
> indicated by the steady numbers for 1971 and 1972 despite an
> unusually snowy winter for 1970-71.  During the relatively snow
> free winters of 1979-80 & 1980-81, deer populations are quite
> stable

On the contrary.  The numbers for '71 and '72 imply a high winter die off.  
Overgrazing of the habitat is further implied by a sharp drop off in '73.  
When one considers that there was a net loss of 150 animals, and there were 
undoubtedly a fair number of new fawns, the implications wrt winter 
starvation are inescapable.  The implications of such a sharp drop are that 
the land was indeed *stripped* by the deer.  This conclusion is further 
supported when one realizes that population continued to drop despite the 
fact that hunting was begun.  The population dropped because the habitat 
could not support higher numbers.  When the habitat improved (it took four 
or five years) the numbers began to increase again.

>  
> 2.  Note the sharp rise in deer from a posthunt reduction of 269
> in 1977 to a prehunt increase of 500 in 1978.  Winters of 1977-78
> & 1978-79 had normal snowfalls but both Feb. of '78 & '79 had
> severe 10-day cold spells (the latter the worst in almost a
> decade).  Since weather does not account for the increase, the
> deer therefore simply had to increased their reproductive rates
> in order to offset their reduction by hunting.

Cold spells bring on the mating season.  This it is reasonable to assume 
that the cold spells may have triggered a more intense mating season 
(mating doesn't end when deer season ends you know....it goes on well until 
March or so I believe).  In addition to this, the land was now more able to 
support the deer, therefore there was an increase in the mating activity.

>  
> 3.  Before the hunt the average deer pop. was about 585.  After
> the deer began to increase their reproductive rates, the average
> 1978-81 pop. was 588.  Whether or not the refuge is "managed" by
> hunting, approx 585-590 deer is the midpoint for the deer cycles.

All that demonstrates is that they're not killing enough deer.  In order to 
maintain a zero growth population, about 40% of the herd must die each 
year.

>  
> 4.  Deer, like other species of wildlife, will attempt to adjust
> their numbers to available food and habitat.  Hunting thus served
> to altered the innate population controls of the animals by
> increasing their reproductive rates.  The purported reason for
> the hunt for reducing the size of the herd to a posthunt level of
> 250 simply did not occur.  Thus one, and only one purpose was
> really served in mutating what was once a true "refuge" into a
> kind of public supported "game farm", namely the PERPETUATION OF
> HUNTING FOR THE HUNTERS.

On the contrary.  It is likely that hunting in this instance helped to curb 
the numbers.  Notice that hunting lengthened the recovery period somewhat.  
Hunting usually doesn't flatten the population curve out, but instead makes 
the peaks smaller and the valleys less deep.  This minimizes the winter 
kill, minimizes the opportunities for disease to infect starved animals and 
so forth.  It looks to me like this place could do with some more hunting, 
not less.

>  
>  
> Reference:  This example and the data are cited in Ron Baker's
>      (1985) book, "The American Hunting Myth".  New York: Vantage
>      Press.

Another to add to my growing pile of references.
>  
-- 
John Robinson                  Only criminals, tyrants, and cowards have
robinson@ac.dal.ca                 reason to fear the armed, honest citizen.
DOD #0069