- Author: Kathy Keatley Garvey
Broken Wing belongs here.
And that's a good thing, because he won't live long.
A male monarch that we've nicknamed “Broken Wing” due to a predator mark, hangs out on our milkweed, butterfly bush and Mexican sunflower (Tithonia). He's probably looking for a meal and a mate. Not necessarily in that order.
Scrub jays watch Mr. Danaus plexippus zigzag over the garden and try to nail him. Missed! Hey, didn't you get the message that monarchs don't taste good?
One scub jay, oblivious to the crippled butterfly, perched on our cherry-laurel lined fence today with an acorn in its mouth. Better that than our butterfly.
Praying mantids in our yard would like to make a meal of Broken Wing, too, along with ants, wasps, and dragonflies, not to mention Jeremiah, the American bullfrog that resides in our fish pond.
One thing's for sure: Broken Wing won't be migrating to an overwintering spot in Santa Cruz or Pacific Grove any time soon. He won't be migrating anywhere.
One of the casualties of predator-prey interactions..,
- Author: Kathy Keatley Garvey
The Monarchs are on the move.
In the late summer and early fall, the Monarchs (Danaus plexippus) head for the California coastline or central Mexico to overwinter.
"Monarchs west of the Rocky Mountains travel to small groves of trees along the California coast," according to Monarchwatch.org. "Those east of the Rocky Mountains fly farther south to the forests high in the mountains of Mexico. The Monarch's migration is driven by seasonal changes. Daylength and temperature changes influence the movement of the Monarch." See map.
It's a good day when we see a single monarch in our Vacaville, Calif. garden re-fueling for the migration. It's a great day when we see two. It's a super, super wonderful day when we see three. It's a time for cartwheels, handstands and pirouettes.
Only a Monarch can get us that excited. Gulf Fritillaries, Western Tiger Swallowtails, and Anise Swallowtails come close. Mourning Cloaks, Painted Ladies and Acmon Blues? Not so much.
The aptly named butterfly bush (Buddleja davidii) draws them all, offering nectar they can neither resist nor refuse. Another nectar favorite in our garden is the Mexican sunfllower (Tithonia).
The female Monarchs are still laying eggs on our milkweed. The result: two chrysalids are hanging in our butterfly habitat container (purchased from the Bohart Museum of Entomology, University of California, Davis),
Soon, we hope, two more adults will begin that amazing migratory journey to Santa Cruz? Pacific Grove?
Who knows? Right now they're precious jade-green jewels studded in gold. We can see the outlines of the treasures they hold.
- Author: Kathy Keatley Garvey
Thank you, Mrs. Monarch.
Thank you for laying your eggs on our newly planted narrowleaf milkweed.
We planted the narrowleafed milkweed last spring, hoping we could coax you to come. We laid out a floral welcome mat for you with some of your favorite (adult) foods: a butterfly bush, Mexican sunflowers (Tithonia), and Lantana.
Then we watched. And waited. And watched. And waited.
We saw you nectaring the butterfly bush, the Tithonia and Lantana. We saw Gulf Fritillaries (Agraulis vanillae) chasing you. We saw territorial male sunflower bees (Melissodes aegilis) dive-bombing you. We saw female Valley carpenter bees trying to jerk you around.
You ignored our narrowleafed milkweed. Not a good-enough host plant? Too many oleander aphids for you? Too many lady beetles eating the aphids?
We went from informal to formal. Please, Mrs. Danaus plexippus, lay your eggs on the Asclepias fascicularis. Please. Do. So. Now.
This week we saw your evidence: You did it! You gave us the most beautiful caterpillars we've ever seen.
So, thank you, Mrs. Monarch.
And you, too, Mr. Monarch.
Please come again.
- Author: Kathy Keatley Garvey
For years we've marveled at the migrating whales passing Point Reyes as we stood glued to our binoculars.
And we've expressed awe that a bird--a plover--makes nonstop flights over the central Pacific Ocean from Alaska to Australia and New Zealand.
Amazing. Nothing short of incredible, especially when you consider that many homo sapiens can't find their way out of a parking lot.
They're all on the move. But how many of us have seen the lesser known migrants, such as winged aphids, ballooning spiders, mites, locusts, pelicans, grasshoppers, and armyworm moths, on the move?
Enter Hugh Dingle, an emeritus professor of entomology at the University of California, Davis, and a worldwide authority on animal migration.
Dingle, who was featured in National Geographic's cover story on "Great Migrations in November 2010 and interviewed by LiveScience for its November 2010 piece on “Why Do Animals Migrate?", has just published the second edition of his book, Migration: The Biology of Life on the Move (Oxford University Press), a sequel to the first edition published in 1996.
The full understanding of migration, or “life on the move,” involves genetics, physiology, and morphology, as well as behavior and ecology, Dingle says.
"The program or syndrome includes specific modifications of metabolic physiology like enhanced fat storage to fuel migration and of sensory systems to detect inputs from the sun, stars, and magnetic field lines to determine compass direction. Intimately involved in the latter are daily and yearly biological clocks. The pathway followed is an outcome of the syndrome of migratory behavior and is part of the ecology that provides the natural selection acting to determine the evolution of migration.”
Not all migration is a round trip; sometimes it's one-way, Dingle says. “Important defining behavioral characteristics are specific departure and arrival tactics and the refusal to stop even in favorable habitats until the migration program is complete,” Dingle says. “In the words of National Geographic reporter David Quammen migrants ‘are flat-out just gonna get there.'"
Why is it important to understand the biological basis of migration and its evolution? “Because migration is so widespread and because migrants have such impact on both natural and man-altered ecosystems,” says Dingle, who achieved emeritus status in 2003 after serving on the faculty of the UC Davis Department of Entomology (now the UC Davis Department of Entomology and Nematology) from 1982 to 2002.
In his book, Dingle covers the interaction between behavior and outcome. Another important focus: he covers the relation between migration and life histories, including the evolutionary genetics of the relationship. Long-distance round-trips, for example, require long lifespans, hence most insects, although not all, migrate only one-way.
“Natural selection acts differently on long versus short lives," Dingle says. "With long lives there are usually many opportunities to produce offspring; with short lives there may be only one. Thus reproductive opportunities may determine when and where to migrate. Migrating aphids postpone reproduction until they colonize new host plants; birds reproduce following migration in the spring, but not in the fall. Some birds and insects use migration to exploit ‘rich patches' and breed in different places in different years or even in the same year."
Dingle, former secretary of the International Society for Behavioral Ecology and past president of the Animal Behavior Society, says he wrote the book for "students of migration and for those biologists who are generally interested in the functioning and adaptations of whole organisms."
Dingle is a fellow of the American Association for the Advancement of Science and the Animal Behavior Society. His research has taken him throughout the world, including the UK, Kenya, Thailand, Panama, Germany and Australia.
In some respects, he, too, migrated.
- Author: Kathy Keatley Garvey
Westward, ho!
The western migration of the Monarch butterflies (Danaus plexippus) to their overwintering sites along the California coast is underway.
Butterfly expert Art Shapiro, distinguished professor of evolution and ecology at the University of California, Davis, recorded four Monarchs at his Suisun monitoring site yesterday. He's been monitoring butterflies in Central California for some four decades.
This morning, a male Monarch fluttered into our yard to sip some nectar from a Mexican sunflower (Tithonia). (A distinguishing feature of the male Monarch: a small black spot on each of its two hindwings. See photo below.)
Monarchs head for sites along the coast, including Santa Cruz, Monterey, Natural Bridges and Pacific Grove, to overwinter, Shapiro noted.
"There used to be a small site in Fairfield, near the old Juvenile Hall on West Texas Street, in a row of Eucalyptus. It's been gone for decades. Some years they try to overwinter in Marin and Sonoma counties, but usually give up and shift south in December. In the past few years there has been a little winter breeding on the south coast. This was never recorded before."
The migration of the Monarchs to overwintering sites in central Mexico is well-publicized, but some monarchs head for the California coast. According to the monarchwatch.org website, monarchs east of the continental divide generally migrate to central Mexico from as far away as Ontario, Canada. "Monarchs west of the divide fly to the coast of California to spend the winter. They cluster together on tree limbs during the winter months in California by the thousands, and in central Mexico by the millions." (Download the PDF on the monarchwatch.org site.)
We're glad to see the huge national campaign to plant milkweed, the host plant of the Monarchs. The Xerces Society for Invertebrate Conservation has posted a wealth of information on its website for us to take action. The Monarch population has declined by more than 90 percent in under 20 years.
“Monarch butterflies are declining due to loss of habitat,” said Monarch Watch director Chip Taylor. “To assure a future for monarchs, conservation and restoration of milkweeds needs to become a national priority.”
It also helps to provide nectar resources for the Monarchs to help them along in their migration. In our yard, they like the Mexican sunflower (Tithonia), the butterfly bush (Buddleia davidii), and blue beard (Caryopteris × clandonensis). See list of Monarchs' favorite plants on the monarchwatch.org site.
Meanwhile, an occasional Monarch flutters into our family bee/butterfly garden to sip some nectar. Sometimes territorial native bees chase them away but the Monarchs return, determined to grab some flight fuel.
Westward, ho!