West Coast Monarchs

[zoovolunteer]

Does anyone know why the west coast monarchs are not being tagged and in the program? I know there aren't as many here but some of us on the west coast have difficulty getting as far as Kansas for the migration periods. I was told they may not be the same butterfly but aren't Monarchs Monarchs? I wonder if the people outside Montery, CA where they overwinter would agree with that. They put a lot of store in their Monarch butterflies, festivals, docents, etc.

[Chip]

There is a great deal of discussion about the conditions under which monarchs should be tagged in the western states. The population is indeed much smaller and may total only a few hundred thousand monarchs in a bad year. In the eastern portion of the US it is possible to tag 100,000 monarchs and yet the ratio of tagged to untagged monarchs is still 1/20,000 (only .00005 0f the total population). There is a good chance that if 30,000 monarchs were tagged in the west that this number might represent 15-30% of the population. When one is dealing with a smaller population, several concerns arise. Are there handling effects associated with the tagging that contribute to the mortality of the butterflies, and if so, even if such effects are slight, is there a way to minimize the impact of tagging. Also, since one is dealing with a small population (of both monarchs and people) and a large territory west of the Rockies, are recapture rates high enough to justify the tagging effort. In the eastern migration, recapture rates run from about a half a percent to 5%. These are good rates but it is possible that proportions of recaptures in the west, especially of monarchs tagged at overwintering sites and dispersing in the spring could be much less. The bottom line is that the objectives of the tagging have to be clearly drawn. Should tagging be encouraged for monarchs originating in western states with the hope that the recoveries at overwintering sites along the California coast will reveal more about where monarchs come from that colonize these coastal locations? Should monarchs only be tagged at one or a few of the overwintering sites to determine how much they move from site to site or on and off sites through the winter months? Should the tagging be conducted in order to get a better estimate of the size of the population? Should the tagging and measuring be conducted to get a sense of the changes in individual butterflies through the season (by measurement at each recapture)?

Because scientists don’t know whether the monarchs east and west of the Rockies are genetically different, every effort is being made not to move monarchs from one side of the Rockies to the other. However, both populations are thought to represent the same species.

[Paul Cherubini]

In recent years, a total of around 30,000 monarchs have been tagged along the California coast each winter by Dr. Dennis Frey's tagging team along the central coast and by Walter Sakai at the Ellwood Main overwintering site in Goleta, Calif. They have been getting recoveries including one east of the Rocky Mountains http://www.saber.net/~monarch/monarchnews.jpg
http://www.saber.net/~monarch/bigsurpueblo.jpg So since western monarchs naturally breed in and cross the Rocky Mountains, alot of people do not think there should be any legal restrictions against shipping monarchs across the Rocky Mountains.

In fact, in Mexico, millions of so called "eastern" monarchs cross the continental divide and end up overwintering in the mountainous region inbetween Morelia and Maravatio, Michoacan.

Dennis Frey may be willing to supply tags to interested individuals. Contact Dennis at dfrey@calpoly.edu

[Megathymus ursus]

I am not an expert here when it comes to monarchs, but Paul's hypothesis seems reasonable. In some places the Divide is totally flat (ie southern NM).

Does anyone REALLY think the Canelo Hills, SE AZ monarch population never crosses over into Chihuahua?

[Paul Cherubini]

In some places the Divide is totally flat (ie southern NM). Does anyone REALLY think the Canelo Hills, SE AZ monarch population never crosses over into Chihuahua?

Yes, milkweed grows right on top of the Continental Divide in places where the Divide is flat:

http://www.saber.net/~monarch/nm1.JPG

and also at numerous locations in Wyoming, Colorado and New Mexico where the Divide is anything but flat:

http://www.saber.net/~monarch/colo.JPG
http://www.saber.net/~monarch/colo2.jpg
http://www.saber.net/~monarch/vail.jpg
http://www.saber.net/~monarch/vail2.jpg

[Megathymus ursus]

I have wondered... how many of us have thought of paying, like, college campuses (which tend to be ecologically conscious, at least in their ideals) to cultivate large quantities of milkweed on their properties?

[ButterflyLdy]

When I lived in Boise, Idaho, we did tag the monarchs that we raised. I lived next door to a science teacher who raised monarchs every year and who worked with a woman in Boise who supplied her with tags. My children helped her tag for several years.
Rebecca

http://www.librarylady.us/butterflylady.html

[tdogmom]

I live in Southern California and last year I tagged close to 75 of them!

[Mona Miller]

I live in Southern California and last year I tagged close to 75 of them!

Where did you get your tags?
http://www.gilroygardens.org/butterfly.html
Gilroy Gardens in Gilroy, CA tagged in 2006, they did not tag in 2007 due to the lack of Monarchs, they plan to tag in 2008 if there are enough Monarchs.