Migration Update: October 8, 2009
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Your Sightings!

This Week's News:

Photo of the Week

Photo: Wayne Kryduba

How is this monarch preparing to fly?

The Migration: Maps and Questions

Monarch
Fall Roosts

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PEAK
Migration Events

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ALL Monarch
Migration Sightings

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Distribution Map

Learn About Migration Maps

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Make Your Own Migration Map


For Your Journal
This Week's Map Questions

Latest News

A Big Week in the East!
Observers along the Atlantic Coast witnessed the strongest migration of the season this week, and October 5th was the biggest day yet.

  • New Jersey's Cape May Monarch Migration Project monitors migration daily and reported their highest count of the season on Monday--101 monarchs per hour. Their weekly average was 89 monarchs per hour, up from 23 per hour the week before. (See their season totals.)
  • Also on Monday, observers on Virginia's Assateague Island estimated a peak count of 620 monarchs one hour according to Denise Gibbs. She tagged 100 butterflies.

Why so many monarchs? What kind of weather produces strong migration on the Atlantic Coast? A west wind was blowing all along the coast on Monday, from New Brunswick to North Carolina. Westerly winds push monarchs toward the ocean, so the butterflies travel down the shoreline to avoid being blown out to sea. Denise Gibbs made a fascinating observation: "All but 2 of the 100 butterflies tagged had extremely lean abdomens, most likely from the ordeal of being blown over the ocean and having to struggle by flapping nonstop to get back to shore."

  • The same day, on the Massachusetts coast, Greg Stone saw monarchs migrating among hundreds of tree swallows. He snapped this picture. Can you find the monarch? The picture is a reminder of the cause-and-effect relationships in the timing of migration: Tree swallows eat insects. Insects are vanishing now because of cold temperatures. Across North America, millions of insect-eating birds must migrate quickly, like the swallows pictured here.

A Second Wave: Great Lakes to Ohio Valley
Thanks to the reports from so many observers, we seem to have picked up a second wave of migration this fall. Perhaps due to warm temperatures in September, a late group of monarchs appeared during the past week. Beginning in the Great Lakes region, sightings then spread into the Ohio Valley states. A roost in Indiana stands out like a stepping stone in a migration pathway out of Canada. (See roost map.) This roost is a full month later than those that appeared in August. Among those who reported their highest monarch-per-minute counts this week were these students in Kentucky and Ohio:
  • In Kentucky, Cub Run Elementary "saw 8 monarchs in 24 minutes during our recess."
  • In Ohio, Grand Valley Elementary "observed 6 monarchs flying southwest while we were out for our 30 minute recess."

Poised in Texas to Enter Mexico?
Our migration map seems to show monarchs stacked up in the Texas Central Flyway. These monarchs are poised to enter Mexico in large numbers, probably with this week's cold front. Get your Spanish/English dictionary ready: We expect sightings from our Mexican friends in the Correo Real program. Let's see what happens!
Can you find the monarch?
It was migrating among 500 tree swallows on Monday in Massachusetts.
Photo: Greg Stone


 

News from the Monarch's Winter Home: Spanish & English

"It feels like the monarchs should arrive soon!" writes Estela Romero from the monarch's winter home in Michoacán, Mexico. "Se siente que las monarcas llegarán pronto!"

Estela Romero lives in the small town of Angangeuo. The monarch's winter sanctuaries are in the surrounding mountains. She took a walk this week to check for monarchs on a hillside above town, the place where the monarchs traditionally arrive first. It's the rainy season from May to October in central Mexico but this year has been unusually dry, reports Estela. "We hardly saved our corn crops this year," said a boy whom Estela met on the trail.

Maria Estela Romero
reports from Angangueo.

Slideshow: Too Cold to Fly?

This fall's first frigid temperatures are moving across the continent right now. What are the effects of temperature on fall migration? The butterflies must leave their northern habitat before they get trapped by the cold! Study these temperature maps to see how little time they have to travel.

Monarchs are cold-blooded. They can't fly unless their flight muscles are warm enough. With each passing day, monarchs have a smaller and smaller window of time in which they can fly. The days are getting shorter and temperatures are falling. Explore how cold temperatures affect flight and migration, in this week's slideshow:

Links: Monarch Resources to Explore

Monarch Butterfly Migration Updates Will be Posted on THURSDAYS: Aug. 27, Sep. 3, 10, 17, 24, Oct. 1, 8, 15, 22, 29, Nov. 5...or until the monarchs reach Mexico!

The Next Monarch Migration Update Will Be Posted on October 15, 2009.