Vanessa at night - no 3

[Paul Cherubini]

> Paul Cherubini wrote:
> >
> > latitude butterfly flying in the middle of the night.  Your observations
> > do not meet the following conditions:
> >
> > 1. well away from artificial lights
> > 2. in the pitch black night sky (well after sunset & well before sunrise
> > in temperate zone latitudes (not arctic latitudes in the summer)

Stan Gorodenski responded:

> Who came up with these 'conditions' that we all must adhere to?  I
> question them.  What is 'well away from artificial light'? 
> What constitutes a 'pitch black night sky'?  What is the specific
> measurable standard for this condition?  Does this rule out moon lit
> nights?  If so, it sure would be an unnatural standard.  

Good questions Stan. 
I just meant the natural conditions that exist at night
on land (or over water) away from cities in temperate zone latitudes
in summer. So, no, I would not rule out moon lit nights. Indeed,
warm, full moon nights would be ideal for studying whether migratory
butterflies are ever flying since human observers can see fairly well under
these conditions.  

'pitch black night sky' = anytime1 hour after sunset to 1 hour before sunrise.

'well away from artificial lights' = roughly a quarter mile away from the nearest
street / building / vehicle light bulb (a mile away from a lighted football field or
sea coast lighthouse).

Paul Cherubini

 
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