Invasion of the not so migratory butterflies

For several weeks now we've been watching thousands of the American snout-nosed butterflies pour over our fence line, always southbound.  They mostly stay above the trees like the 30' Live Oaks shown below.  (Click on the gif photo below to enlarge.)

Many drop lower and end up splatted on cars.  Not to worry say local butterfly experts, there are plenty left to make a bumper crop next year.  With all the rain, conditions were good for butterflies this year.

They are closely following the path of the lowly and ubiquitous Hackberry tree.  Considered a weed tree by most landscapers, this important wildlife food source is plentiful in natural areas along our creek.

With so many growing nearby, I have no problem pulling hundreds of seedlings from my garden each year.  Thank you birds for feasting on the seeds all winter and dropping them in my garden.

Hackberries develop a deep tap root very early which makes them a challenge to pull if I wait too long.

American snout nose butterflies are dull brown and moth-like so they're not the prettiest butterfly but observing their seemingly endless numbers in flight against the summer sky is fascinating.

Where do they come from and where are they going?  They don't go far at all!  Their migration begins 50 miles north along I-35 in San Marcos and ends near the Mexican border in Brownsville, about 250 miles south.  Considering the thousands of miles Monarch butterflies travel twice a year, that's not much distance at all.

Fly high, little butterflies!