Butterfly releases vs NABA counts

[Paul Cherubini]

Michael Gochfeld wrote:
 
> If releases occur close to and shortly before a count they could well
> influence the count results significantly.  If they occur far from a
> count (or after it), they probably won't.

True. I will explain the actual situation in more detail below:

I believe there are only 9 species the USDA will routinely write permits for environmental 
release. These species have huge ranges (e.g. monarchs, painted ladies, mourning 
cloaks, red admirals, buckeyes, gulf fritillaries, etc) in the USA. Assume breeders raise 
and release a total of 60,000 individuals per year, mostly within a 9 month period. That's 
about 7,000 butterflies released per month. The average release event consists of 24 
butterflies at any given location. So that's roughly 291 release events per month at 291 
widely scattered locations around the USA

Now lets make some worst case assumptions and exaggerations: Lets assume 14% of 
those 7,000 butterflies are released in California alone. That means 1000 butterflies 
would be released in California per month. Now lets assume a third of those 1000 are 
released in the Los Angeles Basin. That's 333 butterflies released in the Los Angeles 
basin area (roughly 100 square miles) per month. That's 3.3 butterflies (with a 30 day 
average lifespan) released per square mile per month. OR 1 BUTTERFLY PER 
SQUARE MILE RELEASED EVERY 9 DAYS. At this extremely diluted density level, 
does anyone seriously believe any of these individual butterflies would have a realistic 
chance of being spotted and counted on a 4th of July Los Angeles area NABA census?  If 
so, considering that the species involved are typically fairly common butterflies within the 
Los Angeles basin anyway, could a false record every once in awhile lead us to conclude 
a given species was increasing in abundance?

Paul Cherubini, El Dorado, California