Monarch Butterfly Migration Update: February 21,
2003
Monarchs in the News Population Rebounds, Deforestation Continues
"The data this winter indicate that the monarchs are moving back toward their average population size, which is very encouraging news," said Dr. Lincoln Brower. "But until illegal logging is halted in Mexico's butterfly sanctuaries, the monarchs remain increasingly vulnerable from exposure to storms and loss of habitat." The researchers who measured the colonies this year witnessed illegal logging activities in the core zone of the reserve, in addition to heavy cutting in the parts of the buffer zone.
How News is Made A "press release" is a public statement given to the media by a person, agency or organization, with the goal of receiving press coverage. The press release above was issued jointly by three organizations: The Mexican government, the World Wildlife Fund, and the Monarch Butterfly Sanctuary Foundation. Within 48 hours, hundreds of news organizations, such as these, came out with the story:
Try This!
Deforestation Pressures: Causes and Possible Solutions These maps show the rapid rate of deforestation in the monarch sanctuary area; 44% of the conserved forest was lost in the 15 years between 1984 and 1999. The butterflies need an intact forest to protect them from the elements. The trees serve as an umbrella and blanket, keeping the butterflies dry enough and warm enough to avoid freezing. In the coming weeks, we'll explore the complex issue of deforestation in the monarchs overwintering area, beginning with this week's story about the domestic wood needs of the local people. Domestic Uses of Wood Ranch Tour With Noemi's Dad Noemi's family lives the traditional mountain lifestyle of Michoacan. On their ranch, they grow almost all of their own food, and they draw additional resources from the forest that surrounds them. Wood is an important resource. We asked Noemi's father to show us the many ways wood is used in their daily lives. Before viewing the video and photos, brainstorm with your class: How many different ways do you suppose the de Jesus family uses wood?
(To respond to this question, please follow the instructions below.) Where Are the Butterflies? Discussion of Challenge Question #2 Students went on a photo safari last week in search of butterflies. Mrs. Nunnally's second grade class in Bedford, NH, said they looked long and hard at the photographs. "We think there are monarchs in photos D and E," they concluded. Mrs. Swentzel and her third grade class also looked carefully. "We feel that pictures B and E contain the colony of monarchs. But picture D has a few butterflies roosting on some of the trees." In describing the colonies they added, "They look like moss covered rocks hanging from the trees in the forest." Great observations, everybody! In fact, D was a trick photo. You can see single butterflies, but those butterflies had flown away from the colonies, which were just over the hill in the direction the people are walking. Why Look Down? Discussion of Challenge Question #3 We asked, "Why do you think we watched the ground when looking for the colonies?" Here's what people imagined we were looking for:
We were indeed watching for butterflies, dead and alive. Underneath a colony, butterflies litter the ground like confetti after a parade. And when the colony moves, the wings remain behind. We watched the ground for colorful wings, in case the butterflies were above us, camouflaged in the trees. Three times we came upon distinct areas where there were thousands of wings, but no butterflies above--silent testimony to the life and activity that was previously there. Because the wings remain on the ground for days and even weeks after the butterflies have gone, they leave a trail that tells the seasonal history of the colony. Scientists studying habitat needs can learn which areas are important to the butterflies by noting this litter of wings.
Caution: Video clip of monarchs scattered across the forest floor like fallen soldiers is a little sad to see! WHY are so many dead butterflies on the ground? Predators take a big bite out of the monarch population. "In a typical year, we estimate upwards of 15% of the entire over-wintering population dies due to predatory activities," says Dr. Calvert. (Many butterflies also die without apparent cause--perhaps from starvation.) "Of all the possible predators in the sanctuary area, only 3 prey extensively on monarchs--one mouse species and two bird species."
Who Ate These Butterflies? Challenge Question #6 Read about predation in the overwintering colonies and inspect the three pictures of preyed-upon butterflies carefully. Can you determine who the predators were?
How to Respond to Today's Challenge Questions:
1. Address an e-mail message to: jn-challenge-monarch@learner.org
Copyright 2003 Journey
North. All Rights Reserved. |