California Bay Area Monarch Report

[Bobby Gendron]

September 26, 1997

	Visited a monarch overwintering site in Newark with Christine Arnott.
This site has a small population of monarchs, about 200, and this
congregation will usually break up by early November. Christine and I
were able to tag 50 of the monarchs and this is part of an early fall
tagging study to show movement throughout the various overwintering
sites along the coast of California.

September 27, 1997

	Went to a larger overwintering site in San Leandro with Cassie Smith
and we tagged 300 monarchs. We plan to tag 300 butterflies around the
first of every month. This data will be used to compare movement
throughout the entire winter season. 

September 28, 1997

	Paul Cherubini and I visited two overwintering sites, one in San
Leandro and one in Alameda, to take population counts. We stopped at the
Alameda site first and to our surpise there were over 2,000 monarchs
there, which is a very high number for late September. An even bigger
surprise was the population at the San Leandro site. On this same day
last year I visited the site and there were about 1,000 butterflies
roosting on two trees. Right now there are about 15,000 butterflies
roosting in 5 seperate locations, with one of the locations being a
chain link fence. There were nearly 300 monarchs clustered on the metal
fence. Having 15,000 monarchs at this site in late September is really
amazing because over the past 20 years the average population is around
7,000 - 8,000 during the peak month of November. California Bay Area
overwintering sites should be very large this year considering that the
migrants are still coming in by the hundreds and they are still being
spotted in the Sierra foothills.

Bobby Gendron