TAGGING AND MONITORING MONARCHS
Volunteers have been placing small tags on the wings of monarchs in the western states since the 1960s. Well known monarch butterfly expert Fred Urqhart and his wife Nora founded the Insect Migration Association (1952 - 1977). Their studies included mailing thousands of monarchs from east of the Rockies to specific locations west of the Rockies in order to gain a better understanding about autumn migrations in the west. The Urqhart’s provided some interesting data that later corresponded to the natural direction of autumnal monarch movements in the west based on tagging programs.
By the late 1980s, volunteers associated with the Los Angeles Natural History Museum and the Monarch Program established annual field trips to western overwintering sites to tag monarchs, often called tagging parties. Interest from the public, media, and scientific community developed rapidly.
A tagging party
Ten years later, there were enough butterflies captured, tagged, released, and recovered to reveal general movements throughout the western states and distinct patterns of migration and dispersal from overwintering sites in California -- especially southern California where little was previously known. These map links show autumn and spring movements west of the Rockies based on tag, release, and recaptures. Black lines represent autumn flights and red lines illustrate spring flights from coastal overwintering sites.
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click each to enlarge
Tagging monarchs continues into the 21st century in order to learn more about how climate trends and human encroachment affect their migration patterns and populations. More attention is now given to regions where limited monitoring or tagging has been conducted in the past; for example, in Monterey, Santa Cruz, and Bay Area Counties.
A new group of volunteers in central California recently started an organization called Monarch Alert. They are tracking spring movements of monarchs from San Luis Obispo County north to Marin County. Local groups along the coast of California from communities where monarchs spend the winter are joining together to help protect habitats and learn more about saving a threatened natural phenomena. Tagging monarchs and tracking their migration will give conservation groups more answers when dynamic questions emanate from developers, city councils, or people from the community that have no interest in preserving an area infested with insects (a belief shared by the people that occupy the high mountain ranges of central Mexico).
Annual Thanksgiving Monarch Butterfly Count
A monitoring project called the Thanksgiving Monarch Butterfly Count was started
by members of the Monarch Program in 1997. It is similar to the Audubon
Society's Christmas Bird Count and the North American
Butterfly Association's Fourth of July Butterfly Count. These two organizations
count the number of different species, whereas the “monarch people”
only count the total number of one species at numerous overwintering sites.
These numbers are estimates of how many butterflies are in aggregations, perching
individually on foliage, and/or flying. Weather conditions, preferred
roosting trees, numbers mating, peculiar behaviors, tagging data, and location
of aggregations are recorded for annual and long term comparisons.
The choice of a Count in late November is because most monarchs in the west
arrive along the coast and locate selected groves of trees during this time.
The Count period is basically from 15 November through 10 December. Climate
changes usually occur before the winter solstice and this change influences
monarchs to shift to more protected habitats. Thus, a study of population
numbers in January or February will be very different from those of late November
because the butterflies have shifted to other sites or dispersed.
Numbers of monarchs estimated at overwintering sites for the past ten years
are listed below. These numbers reflect observations from trained volunteers.
Not all butterflies are counted, however we do have some baseline
data for population fluctuations.
Autumn and Spring Tagging Data Previously Published in the Monarch Quarterly
From pages 9 and 12, Winter 2001 edition (below):
From pages 9 and 12, Spring 2001 edition
(below):
Stevens and Frey 7/23/2004