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| Monarch butterfly |
The N.Y. Times reports that the number of Monarch butterflies at their central-Mexico winter home is down about 59 percent – the lowest since record-keeping began almost 20 years ago. There are now only one-fifteenth as many as there were in 1997.
All the Monarch butterflies in the world spend winters in a fir forest in the mountains of central Mexico – in the state of Michoacan. They come from all over Mexico, U.S. and Canada, driven by an inherited urge; it is almost impossible for a specific butterfly to be in the forests of Michoacán for two successive years since they have such a short life span. Their migration is purely genetic.
They cluster together by the thousands. The area covered by the butterflies is measured each year. This past winter the "butterfly zone” covered 2.93 acres. That’s down from the previous winter’s 7.14 acres, and the high (in 1996-7) of 44 acres (18.19 hectares in metric). This is the third straight year of declines – the lowest since records began being kept in 1993-4.
Conservationists blame climate conditions
and agricultural practices. These primarily occur is the U.S. and Canada.
Both contribute heavily to the steep decline in milkweed plant. Like all butterflies,
there is a specific host plant on which they can lay eggs, and on which the offspring
can feed and grow to maturity. Milkweed is
the Monarch’s host plant (technically in the “Asclepiadaceae” family
which in north Texas includes Asclepias Tuberosa, commonly known as butterfly
weed, butterfly milkweed or orange milkweed) The butterfly weed [unfair
name, I know] is either orange or red, is native to Texas, and is a perennial flower
about 2-3 feet tall at maturity.
Other main causes for the Monarch’s
decline are climate-related: heat and drought. Unusually hot, dry weather can
kill eggs, meaning fewer adult monarchs. For the ones that can reach adulthood,
unusual cold, lack of water and lack of tree cover in Mexico mean they’re less
likely to survive the winter.
The biggest reason for the population
decline, however, is the liberal use of pesticides and herbicides by farmers
and homeowners, especially ones containing glyphosate. Glyphosate is a
manufactured chemical found in many pesticides and herbicides; but
predominantly in Round-Up. It kills all vegetation and all insects (including butterflies). It’s an artificial chemical found at a great many
stores. It’s probably on most garage shelves right now.
Illegal logging in the protected reserve contributes a little, but such logging has been greatly reduced by increased enforcement and alternative development programs.
My advice, if you want to help turn the Monarch decline around, is to do two things this and every year. First, plant a mass of butterfly weed on your property. Not only
will it be good for Monarchs, it’s VERY attractive. Second,
avoid liberal use of pesticides and herbicides, especially ones containing the
chemical glyphosate, such as Round-Up.
These are things YOU can do right now, not broad long-term problems like
drought and land-use – which you have very little control over.
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| Asclepias tuberosa |
Just last week we were fortunate enough to see a wild turkey in our yard;
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| wild turkey |
strolling casually down the boardwalk through a natural area. Have you seen anything interesting lately?
