Thirty-nine bumble bee records, most from a handful of sites

August 17, 2026Kettle Moraines

Thirty-nine research-grade sightings of the were logged across the Kettle Moraines area in the past 30 days. That is the same figure from both available sources — iNaturalist's species roster and the individual observation records — pulled over the same 30-day window and the same 25 km radius. The dates fall in the late-summer stretch when colonies are provisioning new queens before the season ends. Bombus affinis was once common from the upper Midwest into the Northeast, but its range has collapsed by an estimated 90 percent since the late 1990s, and it was listed as federally endangered in 2017, the first bumble bee species in the continental United States to receive that status. A few strongholds remain, and this stretch of southeastern Wisconsin, with its mix of oak savanna, prairie remnant, and undisturbed ground for nesting and overwintering queens, is one of them.

Queens of this species need to keep finding nectar and pollen right up until they enter diapause for the winter, so a bee spotted now is doing some of the most consequential foraging of its whole life cycle. She is building fat reserves that have to carry her through months underground, alone, before she can found a colony next spring. But the count itself should not be read as a trend. Eight of the 39 records come from Greenfield Park in West Allis and several more from a single address in Waukesha, so the number tracks where people are out looking at least as much as where bees are.¹ What these records establish is presence and activity across the landscape right now — not that the population is stable, growing, or larger than last year.

Separately, and worth noting without overstating its connection to the bees: the ESSENTIAL INDUSTRIES INC facility is currently listed in significant non-compliance with its Clean Water Act permit. The violation on record is administrative — a missed discharge monitoring report — rather than a documented pollutant exceedance, so there's no evidence here of a chemical discharge affecting habitat or water quality. It's a reminder that regulatory oversight in this landscape is uneven, but it shouldn't be read as a threat to the bumble bee population itself.

Anyone walking these trails who spots a bumble bee with the telltale rusty patch on its abdomen can help simply by logging it on iNaturalist. Every confirmed record adds to a thin and valuable picture of where this species is still holding ground — and records from less-visited corners of the moraines are the ones that fill the real gaps.

1. iNaturalist

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