Monarch Butterfly Migration Update: May 30, 2002
Today's Report Includes:
News From the Migration Trail
As predicted, a big surge northward occurred last week. An astonishing 64 people contributed new migration sightings!
The long-awaited warm temperatures finally moved into the northern tier of U.S. states and into southern Ontario.
After essentially stalling for 2 weeks, the migration has now advanced much closer to its position last year (see
below)--narrowing the substantial gap last
week's comparative maps showed.
to Data: Link to This Week's Migration Data
- In South Dakota, Minnesota, Wisconsin, and Michigan, the migration's leading edge has now reached latitude
46-47 N. Although not as abundant in the east, monarchs have traveled as far north as New Hampshire, at 43 N.
- Not only did the migration advance northward quickly, the abundance of monarchs increased dramatically, particularly
in the northern Midwest. In the space of only 6 days, a sudden flurry of reports poured in from Minnesota and Wisconsin.
Those two states reported 25 of this week's 64 sightings--perhaps representing the advance of monarchs stalled
in Iowa during the last two weeks. Several people saw more than one monarch at a time, an uncommon event until
the first spring generation is on the wing.
- Why are monarchs so much more abundant in the Midwest? This spring's migration pattern suggests one interpretation:
Perhaps because the population was so heavily concentrated in Texas in March, the first spring generation has flown
directly northward and recolonized the Midwest first. Scanty reports from the East probably reflect low reproduction
in the southeastern states.
A Note From Journey North's Director
Congratulations to Sarah on Beaver Island!
On a personal note, after the long Journey North spring season, I headed out into the field to enjoy the beauty
spring has delivered. I'm spending two weeks at the University of Michigan's Biological Station, participating
in a research project on Piping Plovers. Only 32 nesting pairs remain in the entire Great Lakes population. To
monitor the Plover's recovery, each bird is uniquely color-banded. This means researchers can recognize individuals,
and welcome them with relief as they migrate back to Michigan from their winter home on the Gulf of Mexico. It's
been fascinating to see which birds come back first, whether they return to the same nest-site, and whether they
chose the same mate. (Nest-site fidelity is much stronger than mate fidelity, researchers tell me.)
Spending the entire day outdoors is a delight. I've been seated in the sand dunes on the shores of Lake Michigan
for hours, with one eye on the Plovers--and the other eye watching for monarchs. Never have I been so sure I'd
catch the first one. But to my surprise, when preparing the migration map this morning I discovered that, only
32 miles away on an island in Lake Michigan--directly offshore from my post--a student named Sarah beat me!
"I am a student taking a class through my university on Beaver Island, Michigan and when walking on the
beach, there was an adult monarch flying along the beach. During the summer months, the monarch population is very
high on this island, and even though the milkweed are now measuring 2 to 5" high, the first monarch sighting
this early in the season is remarkable, especially the fact that our island is 32 miles out into Lake Michigan."
So congratulations, Sarah! I'll continue to watch for my first monarch. And if anyone was wondering whether
monarchs can fly across open water, Sarah's observations are proof.
Stay Tuned: The Monarch Migration Continues!
Other Journey North migrations have come to an end, but we'll continue to track the monarchs until they ve expanded
across their entire breeding range. This normally takes until mid-June, but may take more time this year because
the population is so low.
Please Help: YOUR Monarch Sightings Are Important
This is an ESPECIALLY important year to be watching for monarchs. Even after monarchs have been reported from your
state or province, we want to hear from YOU when you see YOUR first! And, if you don t see your first monarch until
later in the summer, please report it then. The number of sightings reported reflects monarch abundance, so your
observations will continue to be important.
The Next Monarch Migration Update Will Be Posted on
June 6, 2002
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