Chris wrote:

> I have had scientists tell me that there are moanrchs
> reproducing at high elevations in summer in Arizona,
> and it is the progeny of these that populate the breeding
> sites near SPringerville and in southeast AZ. 

Chris, I think the monarchs are reproducing at low to moderate
elevations (under 5,500 feet) in Arizona in April - June. Example:
on April 9, 1988 when lepidopterist Peter Jump saw a tagged
female monarch in southeastern Arizona that was from the Ellwood
Main overwintering site, the asperula milkweed was already up along
roadsides in SE Arizona and by late April the subvertillata (and
presumably tuberosa) milkweeds were up as well. So eggs
laid by such females in April & early May could give rise to a new
generation of adults in May & June.

Joe Billings told me on the phone he found a large monarch
caterpillar in late June (2008?) feeding on tuberosa in SE Arizona.
So with future mapping and searching of spring milkweeds
in Arizona, more spring and early summer caterpillars may
occassionally be found, although few will be found overall
because nowadays as few as 5-10,000 monarchs may move
into Arizona from the Pacific coast in the spring vs.
50,000 -100,000 back in the 1980's when the overwintering
populations were much larger (especially south of Santa
Barbara).

> Are there breeding populations of monarchs in eastern
> Colorado, western Kansas, or the panhandles of Texas
> and Oklahoma throughout the summer?

Absolutely, but there's been a dearth of monarch observers
in the high plains over the years, hence the Journey North
sighting maps show relatively little spring or summer monarch
activity in that region.

Paul Cherubini
El Dorado, Calif.