Animals Monarch butterfly, female

Published on June 25th, 2013 | by Michael Ricciardi


Monarch Butterfly & Many Birds Facing Big Declines, Possible Extinction

Monarch butterfly, female

Female monarch butterfly (photo credit: Kenneth Dwain Harrelson)

Monarch Butterfly Numbers Declined Dramatically Over A 12 Year Period

[Special Note: see the note at bottom for a link to a new bird species discovery!]

The decline in Monarch butterfly (Danaus plexippus) numbers has been transpiring for at least two decades, but in recent years, these declines have become more dramatic.

Each year, vast numbers of the ornately-winged insect engage in their famous, ritual migration — some covering nearly 3000 miles — from habitats in Canada and the US to the lush forests of central Mexico.

However, since December of 2011, there has been a 59% decline in overwintering monarchs in these forested areas, according to reports from Mexico’s National Commission of Natural Protected Areas. Further, over a twelve year period (1997 – 2009), overwintering populations along California’s Southern coastline have shrunk from over a million individuals (located at 101 sites) to less than 60,000 (at 74 sites), according to the World Wildlife Fund.

The International Union for the Conservation of Nature (IUCN), which maintains the ‘red list” of the world’s endangered and threatened species, has proclaimed the monarch butterfly’s annual migration an “endangered biological phenomenon.”

The twin culprits of these dramatic declines appears to be habitat destruction (like so many other endangered species around the world) due to housing and industrial development, road building, and agricultural expansion. In addition, the past year (2012) saw drought and record high temperatures which, according to numerous observations, seems to have triggered an early migration. This early migration, in turn, severely disrupted the insect’s breeding cycle by causing their eggs to dry out.

monarch seasonal migration patterns (credit: Harald Süpfle)

Monarch butterfly seasonal migration patterns. Click on image to see animation (credit: Harald Süpfle)

Secondly, warmer than normal weather tends to reduce the amount of nectar found in milkweed plants — the main food source of butterfly larvae. But the milkweed plants aren’t just suffering from high temperatures; they face an added, perhaps more potent, threat from herbicides. Farmers are increasingly using herbicide resistant (GM) strains of crops, which means that more herbicide can be used on them. But milkweed plants, which are commonly found in areas around farm lands, cannot tolerate the increased dosages of herbicide, and are quickly being killed off.

Despite these worrisome trends, there is some hope for the Monarch. In 2008, the Commission for Environmental Cooperation (set up as part of the original NAFTA agreement), published its North American Monarch Conservation Plan which includes the conservation of overwintering sites and the restoration of  breeding habitat throughout the insect’s 2,800 mile range. However, the conservation plan is not backed up by enforced laws but is based upon “finding incentives” (usually, this means monetary pay-offs) to accomplish its goals.

Helpfully, the Mexican government is working with the WWF and other conservation groups to restrict logging in the forest areas that support the overwintering populations of the migratory insect. Additionally, California and a few other states have made solid efforts in monarch habitat restoration.

The success of these efforts may prove to be the deciding factor in the Monarch butterfly’s near-term survival.

To learn more about butterflies and the various threats that they are facing, check out the popular Ecolocalizer article from 2010: California Butterflies See Big Declines from Eco Double Blow

Some source material for this post came the Sci Am article Royal Descent: Monarch Butterflies Suffer Sharp Drop in Numbers

top photo: Kenneth Dwain Harrelson ; cc -by – sa 3.0

One in Eight Bird Species Facing Extinction

Canada-based Birdlife International — the world’s largest nature conservation partnership — has released a report asserting that, world-wide, one in eight bird species are threatened with extinction, citing unsustainable agriculture and global warming as the primary causes. The report draws upon data collected from 120 of its affiliated national bird organizations

The report elaborates: 1,253 bird species (which is 12.5 % of the total number of known bird species*) are threatened with extinction due to declining populations and/or ranges. Of these, 189 bird species are “critically endangered” which means they are at high risk for extinction in the near-term.

These are not just “exotic” bird species living in remote corners of the globe; many are species common to the US and Canada, like barn swallows and purple martins.

In a press statement, Birdlife International chief scientist Stuart Butchart, commented:

“Natural habitats are being converted and many, many species are losing large parts of their population and their range. Unless we take action now to improve their fortunes, these are species that are going to go extinct in the coming years.”

As an example, Butchart noted that birds in forested parts Southeast Asia and Africa are particularly vulnerable, as their habitat is being cut down to grown oil palms.

Like many seasoned observers of Nature, Butchart sees the decline in bird species as a sign or indicator of where we are heading; a warning that the health of the entire natural world, not just birds, is at stake.

“Birds are fantastic indicators. They are good at telling us where other wildlife is found and their trends also closely mirror what’s happening to other wildlife groups,” he said. “So the fact that many bird species are declining, many are threatened with extinction, really should be ringing alarm bells.”

* These numbers reflect counts from the most recent (completed) year, and do not include new bird species finds, such as the recent, multiple new bird species found in the Amazon, or, the even more recent discovery of the Cambodian tailorbird (in an urban locale environment, no less); such new species finds (especially multiple new finds) are relatively rare.

For more information, visit the Birdlife international website.

Some source material (including quotes) for this post cam from the UPI science article: ‘International bird group warns of extinction threat’






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About the Author

Michael Ricciardi is a well-published writer of science/nature/technology articles as well as essays, poetry and short fiction. Michael has interviewed dozen of scientists from many scientific fields, including Brain Greene, Paul Steinhardt, Arthur Shapiro, and Nobel Laureate Ilya Progogine (deceased). Michael was trained as a naturalist and taught ecology and natural science on Cape Cod, Mass. from 1986-1991. His first arts grant was for production of the environmental (video) documentary 'The Jones River - A Natural History', 1987-88 (Kingston, Mass.). Michael is an award winning, internationally screened video artist. Two of his more recent short videos; 'A Time of Water Bountiful' and 'My Name is HAM' (an "imagined memoir" about the first chimp in space), and several other short videos, can be viewed on his website ( He is also the author of the (Kindle) ebook: Artful Survival ~ Creative Options for Chaotic Times

  • Michael R.


    Thanks for your comment (and nice photos).

    A common mistake is made when people assume that a local variation reflects the global situation. As you are not in a position to see the global (large scale) migration data (the actual counts of those that make it to their traditional over-wintering grounds), it seems that your message here is not much different than, say, talking to you friend on the opposite coast where its raining, and sticking your hand out the window and saying, well, its not raining here.

    It is quite likely, based upon the low counts, that not enough larvae are maturing and joining the main migratory group. When this sort of thing happens, it is customary to look at changes in the food source or chain (and disruptions in the breeding patterns).

    Thus the surmise that fewer milkweed plants is the cause.

    A few yards width of milkweeds lining some fraction of crop field, does not compensate for the total loss of milkweeds that would exist there if the crops weren’t planted in the first place (not that I have anything against crop farming — other than over use of pesticides, NPK fertilizers, and making biofuels from food grains)

    Milkweeds are not roundup ready, but, one could also surmise that perhaps the pesticides are getting absorbed into the nectar (milk) and are killing the larvae. In both cases, the close presence of milkweed plants to crop lands (sprayed) is the fundamental culprit.

    It could be that a very large portion of monarchs is finding another overwintering spot, but this would seem unlikely, and certainly people would notice hundreds or thousand of Monarchs invading their woods.

  • Bill

    Gee, I wonder what line of work Mr. Cherubini is in? Please keep your GMO’s to yourself. Amazing someone with an education can use one isolated example of evidence despite hundreds of other cases that reveal the opposite.

  • Paul Cherubini

    The Monarchs are actually doing fine…they were in swarming numbers along the New England coast last September:

    And in swarming numbers in the upper Midwest in 2010 & 2011:

    I will be filming swarms again late this summer in the upper Midwest. Why so many monarchs? Because billions of milkweed plants are STILL found in agricultural and roadside types of landscapes like these across Iowa and the upper Midwest:

    • Michael Ricciardi

      hi Paul

      Thanks for your comment. This is a common mistake: observation of local variation verses global reality; numbers counted (in some areas, like yours) are not related to the numbers that actually make it to their overwintering homes. The declines noted (by folks tracking total numbers arriving to their overwintering sites) could be due to several reasons, one of which may fewer maturing larvae.

      A “forest for the trees” effect here, I suspect.

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