Forests are often bone dry at the end of the hot summer. When dusty leaves of poison ivy and wild grape vines display the first crimson tinge of fall, underground “yellow-jacket” hornet nests reach their maximum annual size and ferocity beneath brushy fields and woodlands.
The papery hornet nests are packed with nutritious, fat and protein-rich larvae. The grubs are defended aggressively by agitated worker hornets that will soon lie dead after the first hard freeze.
Yellow-jacket larvae are a food source for grub-eaters: black bears and skunks. By night, skunks and bears sniff out the hornet nests and unearth tasty hornet larvae. At dawn's light, you will find a wreckage of shredded gray paper nest and dead hornets whose stingers pulsed ineffectually in the thick fur and tough hide of the nocturnal raiders. Hornet nests are a concentrated source of nutritious fats and proteins particularly important for mammals preparing to lie dormant over several months of impending winter.
Ground hornets typically become most aggressive in late summer when the nests are full of larvae. In dry years, adult yellow-jackets seem particularly ornery and swarm aggressively in collective defense of nests at the slightest provocation. The scent of stinger venom further infuriates hornets who seem suddenly as thick as mosquitoes. Standard operating procedure is to scream: “Bees - Run!” in cartoon-like cliché, hands waving while pursued by the angry swarm.
My maternal grandfather, an old Swedish woodsman, had been known to call the ground hornets: “Jello-yackets” Like their stings, that's sort of funny now - taken in hindsight.