It’s a lovely coincidence that here in California, the holiday season is Monarch butterfly season. We bring you this post (partially based on a post from SutroForest.com, used with permission) to celebrate the season with butterflies.
We wish all our readers and supporters a wonderful holiday season, and a happy and fruitful year in 2016.
THE WESTERN MIGRATION OF THE MONARCH BUTTERFLIES
Unlike the Monarchs east of the Rockies (which migrate from Canada to Mexico and back), the butterflies in the West migrate between the interior and the coast. The butterflies east of the Rocky Mountains go south to Mexico in winter. The butterflies on the Western side come to the California coast in search of warmer, milder weather than the inland winters.
From November to February, monarch butterflies gather in thousands in tall trees by the coast.
One of the wonderful things eucalyptus trees do is provide wildlife habitat. In particular, they are crucial to supporting the Western Migration of the the Monarch butterflies, by providing a roost for the butterflies to spend the winter. A study by Dennis Frey and Andrew Schaffner of 300 over-wintering sites showed that three-quarters of them were in eucalyptus trees. In fact, there’s some evidence that the butterflies’ Western migration exists because of the eucalyptus trees.
Most winters, you can see the butterflies at Natural Bridges State Park, about an hour and a half south of San Francisco. Some years they’re even found right in San Francisco, in places like the Presidio and Treasure Island. This is one of those years: The Monarch butterflies came to San Francisco and also to Oakland’s Aquatic Park.
MONARCH BUTTERFLIES IN SAN FRANCISCO IN 2015
Janet Kessler visited the Presidio and took these lovely pictures of Monarchs on the eucalyptus trees there. They’re published here with permission.
CHILDREN DRAW MONARCHS
Also in celebration, we’re proud to publish these pictures from Girl Scout Troop #61902, sent in by Alma Sorenson, Troop Leader:
Monarch Butterfly – by Grace M.
The Monarch in Golden Gate Park – by Addy
Take Flight – by Emma
One Monarch in a San Francisco Eucalyptus Tree – by Angelina S.
Monarch Butterflies Love Eucalyptus Trees – by Lindsey D.
Girl Scouts: Building girls with courage, confidence, and character who make the world a better place
From Ms. Sorenson:
“We are a troop of twelve 4th and 5th grade Juniors from five different San Francisco schools focused on learning and earning Girl Scout badges, and on serving our community.
“We have our donated time and our cookie money to My New Red Shoes, the SFSPCA, and Project Open Hand. This year we will continue our theme of helping kids in need and on the environment.
San Francisco Forest Alliance 
Let us hope the Presidio doesn’t remove their Eucalyptus trees…
The policy for tree management in the Presidio is unique in the San Francisco Bay Area. The policy is consistent with the mission of the National Park Service to maintain historic landscapes. They have made a commitment to maintain the historic forest that was planted by the Army about one hundred-thirty years ago. However, where the forest spread naturally, the Presidio has destroyed the trees in favor of restoring the native landscape that preceded the forest. The Presidio has invested heavily both in restoration of the native landscape and preservation of the historic non-native forest. The Presidio forester has evaluated the health and hazards of the historic forest and is engaged in a long-term reforestation of the same or similar species. He has planted several different species of eucalyptus as alternatives to the blue gum and is evaluating them as they grow.