Vanessa at night - no 3

[Martin Bailey]

 Paul Cherubini wrote:
 '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).

The majority of observors rarely have the opportunity to be a quarter of
mile away from artificial lights at night.  And it is the rare few that
venture out into the night on darken roads and see vehicles without their
lights on passing them by.

As a generalization, butterflies are not active on cool cloud filled days.
However, when they migrate they can be victims or beneficiaries of changing
circumstances while they "are on the road."

As an example,  Tree Swallows are early northern migrant in the spring here.
While they may have come up on a warm front, it is not uncommon for the
weather to change.  It gets cold again and the bugs that the Tree Swallows
must snare out of the air are no longer flying.  The swallows are now in
danger of dying of starvation and cold.  With luck they will find a hollow
and stuff themselves into it - where they at least get warmth.  If the cold
continues on, the swallows die together in their cubbyhole.  If it warms up,
the swallows leave their shelter to hawk insects for yet another day.

It has already been stated on this listserv that butterflies will manage to
continue to fly in wind conditions that they would never venture out into
when they are on migration.  They probably navigate without the benefit  of
humanly visual light.  And it has been hypothsized that they can continue on
in temperatures that they would not start out at.

One has to be careful when generalizing on one's own field experiences.  The
range of butterfly adaptations is probably  greater than we presently know
them to be based on our own localized experiences.  Inputs to this listserv
comes from folks from all over the world who believe it or not can read and
write in more than one language and bring a range of experiences to this
forum.

Martin Bailey,

greetings from:  Weyburn, SK., Canada.
                         49.39N  103.51W


 
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