Jizz

Michael Gochfeld gochfeld at eohsi.rutgers.edu
Sun Jun 17 09:08:58 EDT 2001


I agree with Norbert that with experience, many butterflies can be 
identified in flight and at a distance.  The fluttering of the Least 
Skipper (Ancyloxypha numitor, my favorite scientific name), for example 
is really characteristic. 

I already mentioned how impressed I was that Art Shapiro could identify 
Duskywings (Erynnis) near Davis, CA, before they were in his net. Norb 
commented on this group particularly which is a particularly tough genus 
in the east was well (wear imparts more differences with species than 
the between species differences).

Bird watchers call this the "jizz" (after World War I or II, aircraft 
spotter jargon) which combines shape, behavior, etc. leading to an 
identification even when there is not enough time to get the binocs up. 

However jizz can be deceptive even for birds. It is odd that some of the 
rarest birds are the ones you just glimpse (where it is likely that the 
jizz that registered did not include enough cues).

Anyway, Roger Tory Peterson commented on this in the mid-1900's, 
remarking on how a Chesapeake Bay guide could identify duck species at 
the limit of vision.  Peterson noted that each species had a slightly 
different shape or wingbeat (even when pattern could not be detected), 
but added that the guide also was familiar with where on the bay certain 
species occurred. In otherwords, habitat is an important contributor 
identification. Norb added to habitat, phenology, knowing what is likely 
to be flying helps exclude (thought not always correctly), things that 
would be unexpected. 

A purist might add that just because something is unlikely or unexpected 
doesn't mean it should be unidentified. 



Mike Gochfeld

 
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