Why so many fall 2004 new U.S. butterfly
in South Texas?
I attribute the plethora new records to the following
1) An order of magnitude more butterfliers looking on a daily basis
than traditional lepidopterists who usually only visit the Rio
Grande Valley on an occasional basis. Probably every single fair
weather day from mid September to mid April has one or more people
checking known butterfly hotspots in Hidalgo Co., and less frequently in
adjacent Starr & Cameron Counties. During the height of the
butterfly season, roughly from mid October to mid December, 10, 20, or
more people check Hidalgo County's known hotspots daily.
2) Knowledge of people looking has greatly increased. People are
noticing and (mostly) correctly identifying the subtly different species
with great regularity. Glassberg's field guides got the
field-identification ball rolling with excellent photos of living
butterflies. Recently published guides covering the RGV such as Bordelon
& Knudson (2002), Brock & Kaufman (2003), and Garwood &
Lehman (2004) have been instrumental in education people.
3) Digital cameras and personal websites. With the fairly easy to use
"digicams," people can shoot more pix and discard later.
Photographers can post their images to personal websites at the end of
the day thus alerting others about what's being seen and where. (I try
to gather in the more important records from the various personal
websites and cross-post them on the NABA
site as something of a "central depository.")
4) There's more butterfly habitat being created almost on a monthly
basis. The first prominent butterfly garden planted in the Valley was at
Santa Ana NWR visitor center (in 1999?). That one garden I think made a
very big impression on people across the Valley. Visitors were able to
get out of their cars and immediately see large numbers of common to
rare butterflies. Since then the number of backyard gardens has grown.
Plus every park, refuge, and nature center that I know of in the RGV now
has added additional butterfly host and nectar plants. Our knowledge of
which plants "work" in the Valley is pretty good. Probably the
single best nectar plant is Eupatorium odoratum. This plant, if
watered, grows remarkably fast. Once you put in a couple of "Eups",
you quickly get a whole lot more volunteer plants.
5) The amount of rains the Valley has been getting over the past two
years is above average. This is a very significant factor. The off the
charts number of new records in the late 60's and early
70's was also a very wet period induced by several hurricanes
through the area. When I was living in the Valley in the late 1990's the
region was in the grips of a significant prolonged drought. There wasn't
much rare butterfly activity outside the high season of October to
November. (There were also fewer people looking, less habitat, fewer
resources, etc. then.)
6) Communication, the Internet and cell phones. When something really
rare shows up, people can call others directly cell phone to cell phone
from the field. In this way, multiple Mexican butterfly strays are often
seen as they frequently emigrate north in something of a wave. TX-Butterfly
listserv and email in general allows people just back from the field
to consult others across the continent for near immediate assistance.
Websites disseminating information relevant to the Valley include: NABA-SoTX,
and recently the Guanacaste
This word-of-mouth can and does travel far and wide. When I was down
last October for the Texas
Butterfly Festival, I met many people who already knew what
was being seen before they arrived. The annual (long after-the-fact) Season
Summary of the Lepidopterists' Society with its long list of
scientific names sans corresponding common names and with no more than
one or two black and white photos doesn't generate the excitement among
the masses that an email shouting NEW US RECORD!!! can. Such an email
with a web link to one or more color photos offering proof of the
record's veracity induces the kind of excitement causes people to want
to buy plane tickets...
7) The Texas Butterfly
Festival. This festival is advertised nationally and gets a lot of
local press as well. We regularly have prominent lepidopterists such as
Drs. Pyle, Opler, Glassberg, Acorn, the Tveten's, etc. telling everyone
down there how unique the Valley is from a diversity stand point. People
that come down and see for themselves take their stories and their
photos back home. The festival's field trips show hundreds of people
specifically where the hotspots are and ID a large percentage of the
butterflies on the wing at the time. A number of people stay in the
Valley beyond the end of the festival and continue to butterfly. The
very popular Rio Grande Valley
Birding Festival hosted by Harlingen also creates butterfly buzz as
mid-November is usually still quite good butterflying. These festivals
reinforce the need for more habitat.
8) Global Warming effects (e.g. Crozier 2004) on the Tamaulipan
butterfly fauna may also be a contributing factor. While there are
some 300 species of butterflies recorded from the Lower
Rio Grande Valley, nearly twice that many are known from the
adjacent Mexican state of Tamaulipas, which has the highest biodiversity
of Mexico's northern-most states (Luis et al, 2003).
Mike Quinn, Austin,
Bordelon, C. & E. Knudson., 2002. Illustrated Checklist of the
Lepidoptera of the Lower Rio Grande Valley, Part 1 : Butterflies.
Houston, Privately printed. viii, 84 pp. 20 plates.
Brock, J.P. & K. Kaufman. 2003. Focus Guide to Butterflies of
North America. Houghton Mifflin Co., Boston. 384 pp.
Crozier, L. 2004. Warmer
Winters Drive Butterfly Range Expansion by Increasing Survivorship.
Garwood, K. & R. Lehman. 2004. Butterflies of Mexico: Tamaulipas,
Nuevo Leon, San Luis Potosi Privately Published. 97 color plates,
approx. 750 images.
Glassberg, J. 1999. Butterflies Through Binoculars, The East. Oxford
University Press, Oxford. 400 pp.
Glassberg, J. 2001. Butterflies through Binoculars, The West. Oxford
Univ. Press., New York. 352 pp.
Luis, A.M., J.B. Llorente, I.F. Vargas & A.D. Warren. 2003.
Biodiversity and biogeography of Mexican butterflies (Lepidoptera:
Papilionoidea and Hesperioidea). Proceedings of the Entomological
Society of Washington 105(1):209-224.