chance of encounters

[Michael Gochfeld]

Picky Liz wrote: 
 >Say 100 monarchs are released in a residential area. If these 100 
butterflies disperse over a 20 square mile area after two days this 
means 
there are 5 monarchs per square mile. That's 5 monarchs per every 640 
acres. Since the average home sits on very roughly 1/5 acre, that's 5 
monarchs per every 3,200 homes in the area or one monarch per 640 homes.

That's assuming they don't move.  There may be only one per 640 homes at 
any one time, but if each one flies over 100 homes, that potentially 
means 
a lot more people might see it.

Just feeling picky,
Liz
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In our community, the number of houses with butterfly gardens or even 
with butterfly flowers is less than 10%. So the butterflies aren't 
randomly distributed.  Moreover, they do move.  On a day when we thought 
we had about 3 Monarchs in our yard more or less all day, tagging 
of 12 individuals showed that they were moving around. 

Mike Gochfeld 


 
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