the doldrums

[Chris J. Durden]

In Central Texas I have found the diversity peaks occur at three times of 
year.
    First peak is at the beginning of the spring period of probable 
rainfall in late April (days 110-119).
    Third peak is at the beginning of the fall period of probable rainfall 
in early October (days 270-279).
    Second peak seems to be the result of the progeny of the first peak. It 
occurs at the time of the usual hottest day in mid July (day 190-199). Our 
Austin Urban butterfly Count has been held during this ten-day period. We 
used to have regular good counts before the introduction of the imported 
fire ant around 1986, although under drought conditions count day can be 
miserable with more hungry/thirsty mammal sightings than leps. Since the 
population and diversity crash following the fire ant invasion our count 
day has been an exercise in monitoring the gradual recovery of the 
butterfly fauna to about half its former abundance and diversity.
    Over the years we have recorded 109 species during the days 190 to 199.
    I think taking a conventional count during the spring or fall diversity 
peaks would be much less representative of the health of our butterfly 
fauna because of the impossibility of obtaining numbers representative of 
the actual population size of the many species swarming at these times. If 
I were to attempt to measure these peaks I would need to employ a team of 
expert identifying collectors for at least two count days during the count 
interval - the first to capture, identify and mark, the second to capture, 
identify and score marked recaptures. I see no way of obtaining 
representative numbers from sight estimate counting under these conditions.
    Here in Austin the 4th of July usually (nothing is ever usual in Texas) 
falls towards the end of the June doldrums of light to heavy drought. It 
tends to be rather disappointing. That is why the Austin Urban Butterfly 
Count is held by the Austin Aurelians (anyone who has been on one of these 
counts) hosted by the Balconian Naturalists' Group on the first Saturday on 
or after the 10th of July, with shift to Sunday in case of heavy rain on 
Saturday.
.................Chris Durden

At 11:39 AM 6/25/2001 -0400, you wrote:


>Numerous posts have come into the carolina leps bulletin board in the last
>week relative to the "doldrums" - as the thread has been called.  I had
>wanted to post on this but did not as I felt the "birderwatchers" would
>just think I was picking on them. I am thus so thankful that the leader of
>the watchers in the Carolinas posted the above bit of absolute truth and
>wisdom.
>
>Butterflying on the 4th of July is next to worthless here in the deep
>South. It may be great in Maine or the Sierras but not in lower North
>Carolina, South Carolina, Georgia, Florida, Alabama, Mississippi,
>Louisiana, Arkansas, much of Texas, non-montane Tennessee, etc.  If there
>is any Birder tradition that is for-the-birds when it comes to butterflies,
>it's the 4th of July "count". As I told someone who wanted to have a 4th
>count at their nature preserve recently - I don't even go out that time of
>year. In the Appalachian mountains good stuff is out then - but not in the
>hot humid sweat belt.
>
>In our region the counts need to be as Harry suggests - one for the spring
>species and one for the fall species.
>Ron
>
>
>
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