Thread: Monarchs
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Old 07-24-2018, 11:32 AM   #25
weedy feilds
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Join Date: Mar 2018
Location: WI
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Quote:
Originally Posted by KC Clark View Post
Just dawned on me that I failed to post about a new monarch study that was published in the June 22nd edition of Science. Main point found by the research is summer population number does not jive with overwintering population number. Counts show plenty of monarchs in the summer but too many migrating ones aren't making it to Mexico. The trip south is getting tougher for reasons known and unknown.

Back when I learned about the study, a PDF of the study was downloadable from Science website. I just checked and the only thing free now is the summary. I screwed up and I'm sorry. OTOH, Science is a magazine most libraries carry so it is something you can get your hands on.

Mechanisms behind the monarch's decline | Science

http://akdavis6.wixsite.com/monarchscience/single-post/2018/07/02/New-study-provides-more-evidence-that-milkweed-is-not-the-answer-to-the-monarch-decline---its-the-migration-that-matters

I would expect that. Its a long path to take to Mexico, there has to be some mortality. Sudden freezes, severe storms, getting hit on the highway, lots of potential mortality.



Question is what is a normal range of mortality?
What % is needed to replace the numbers that went north in the previous spring?
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