[NatureNS] Estimating (guessing) numbers of birds

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From: Nancy P Dowd <nancypdowd@gmail.com>
Date: Tue, 9 Jul 2013 10:32:45 -0300
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You have convinced me to submit my sightings as numbers on eBird. Now I will have to persuade my brother (a statistics prof himself) of this. 

He still feels that presence/absence (x or blank) is the only reliable report for these bird surveys. Despite the limited statistical analysis that can be done on such data. 

Nancy

Sent from my iPhone

On 2013-07-08, at 12:12 PM, iamclar@dal.ca wrote:

> All:
> 
> Nancy's dilemma and suggestions on estimating numbers for eBird are important. I have been a frequent user of eBird, atlas, CBC, BBS, etc., over the years in estimating trends and patterns,. I believe the dictum of a statistician colleague that "a large number of bad numbers (as long as not biassed) are as good as a small number of good numbers" (a recasting of the "law of large numbers"). Even the casual reporting of numbers like "lots" or "common" on naturens are less useful for section editors of "NS Birds" than are estimates.
> 
> Nancy suggests that a range of categories could be available on eBird 2-10, 11-50, etc., but the "users" of these numbers would still have to turn these into a single number for trend analyses, etc. I believe that an educated guess is better; Why not just take the rough number between 11 and 50, e,g., that you think might be better - 20 or 40?
> 
> Another possible guide might be that used during the first (1980s) NS Atlassers of entering log categories 1-10, 10-100, etc. (natural logs even better). Then (as was done) the user (or indeed the observer) can use the geometric mean (about 3, about 30, etc.).
> 
> Cheers, Ian
> 
> Ian McLaren
> 

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