Dear Journey North,
and fall migration are quite different to observe in Texas. I'll
describe them for comparison:
It’s not dramatic, actually, what you see in Texas in the
spring. You never see too many monarchs at once. You may see one
or two an hour, and that would be a good spring migration. Sometimes
along the coast you may see ten or twenty at once, but that would
be during a very strong migration. The reason you see so few in
the spring is because there are far fewer monarchs alive in the
spring than in the fall. There has been mortality at the overwintering
sites in Mexico and mortality along the migration. Your chances
of seeing high numbers of monarchs at once are not good. They’re
just too dispersed.
In contrast, during the fall migration, you can see many, many,
many monarchs at once. It's not uncommon to count hundreds in
an hour in Texas, if you're in the right place at the right time.
Sometimes when the butterflies are being blown by the wind you
can see hundreds in the sky at a time. You also might see hundreds
at once at two times during the day: Mornings
when they’re just leaving roosts, and also in the evenings
when they 'fall out' of the sky and come down to roost.