From: young@alw.nih.gov (Jeff Young)
Newsgroups: talk.politics.animals
Subject: Re: Case Example #1
Date: 6 Apr 92 13:37:10 GMT
Organization: National Institutes of Health, Bethesda, MD


Rather than get into a pissing match with Ted, (I'll do that 
in another post) I'll repost my second query about this data 
on which he would have us base our wildlife management efforts:


____________________begin

Forgive me for being so brief in my analysis of the data:

Article: 4678 of talk.politics.animals
 
Deer Pop. at the Great Swamp National Wildlife Refuge
 
Year     approx.   # of deer  % of     approx.  Number   Number  
        prehunt    killed     herd   posthunt   of surv.  of mig.  
         pop                killed    pop.       fawns     deer   
------|--------|-----------|-------|---------|---------|--------|
1969      520     NO HUNT                         
1970      600     NO HUNT                       80+/-       ?        
1971      650     NO HUNT                       50+/-       ?         
1972      650     NO HUNT                        0+/-       ?        
1973      520     NO HUNT                     -130+/-       ?
1974      570     127        22%      443       50+/-       ?
1975      456     106        23%      350       13+/-       ?
1976      385     128        33%      257       35+/-       ?
1977      375     106        28%      269      118+/-       ?
1978      500     104        21%      396      231+/-       ?
1979      600     178        30%      422      204+/-       ?
1980      650     149        23%      501      228+/-       ?
1981      600     150        25%      450       99+/-       ?
 
 
Add to the number of surviving fawns for each year the unknown
number of deer which did not survive that year's winter.
The number of migrating deer is not known.

Now, what can we conclude from an inspection of the above chart?
 
 
1.)  Deer can triple and quadruple their reproductive rates from year
     to year in response to hunting pressure.  Note the year 1976
     where a herd of 350 deer produced 35+/- surviving fawns (for
     a rate of 0.1) and the following year when a herd of 257 pro-
     duced 118+/- fawns (for a rate of .46). 

2.)  Deer reproductive rates will naturally decline while the intro-
     duction of hunting into the area will cause reproductive rates
     to increase dramatically.  Note the marked decrease in reproduct-
     ive rates in the years previous to the introduction of hunting
     and the explosive rates of reproduction thereafter.


and etc.

Now, what can I conclude from an inspection of the above chart?

1.)  Not a whole heck of a lot other than the general comment that
     the study wasn't designed well.  I would say that the number
     of surviving fawns and the number of deer migrating into the 
     area are important figures.  With those figures in place, I would
     be able to conclude more about the area.  I would also conclude
     that this study was done with a single census taken in the fall of
     the year.  By taking a second census in the spring of the year
     after the years fawns have been born, the study could be improved
     immensly. If funding prevents a second census, I would submit
     that the single census should be performed in late spring and that
     the number of fawns should be noted at that time.  Before anyone
     asks, the fawns are the ones with the big white spots.

2.)  Or,  the study was designed correctly and was preformed and compiled
     by blundering idiots.


"Figures don't lie
but
Liars can figure" 

           My Dad

I suppose someone might have said it before he did, I only know it's
something that he used to say.

__________________end

I will concede that my original post was breif and premature as
was pointed out by Tim Rigg.  I immediately followed with the 
post above - which was completely ignored.  I willl concede that 
a herd of 269 deer could produce 231 surviving fawns in a spring.
I maintain that barring any catastrophic conditions that same
herd would continue to be as prolific in the years that follow.
This data does NOT indicate the response to hunting by the deer
herd was to increase the collective reproductive rate.

Please explain years like 1972 and 1973.  The deer were:

a)  Preforming "safe" sex.

b)  As many starved to death as were born.

c)  As many starved to death or left the refuge as were born.

d)  The methods of census are highly inaccurate.

e)  A wild conclusion by Ted.

 
--
___________	
	jy
	young@heart.dcrt.nih.gov