Dromogomphus spinosus
In 3 days ~10% in a week ~30%
Dromogomphus spinosus, the black-shouldered spinyleg, is a species of dragonflies in the family Gomphidae. Like other spinylegs, D. spinosus have long spines on their legs that help in the capture of prey. True to their name their shoulders are black. The dorsal thorax has a light green I-shaped mark with pale ovals on either side. Their flight time is between late May and early September from southern Manitoba to the east coast of the US as far south as Florida. Terminal segments form a club with yellow lateral markings.
Adults average 2.5 in (64 mm). Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Congaree National Park | 🇺🇸 United States | |
| 2 | Shenandoah National Park | 🇺🇸 United States | |
| 3 | Great Smoky Mountains National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Boston | 🇺🇸 United States | |
| 2 | Montreal | 🇨🇦 Canada | |
| 3 | Dallas | 🇺🇸 United States | |
| 4 | Washington | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Black-Shouldered Spinyleg sighting in Boston on a given day, based on 37 verified sightings from GBIF citizen-science data. It is the 320th most-seen of the 1200 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
July and August
In those months about 10% of wildlife watchers report a Black-Shouldered Spinyleg in Boston on a given day, against under 5% in September to June, the lowest months.
Between 11 am and 2 pm
Across all the parks we cover, that three-hour window holds the most Black-Shouldered Spinyleg sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Yes
Of the 4 cities where we can rate Black-Shouldered Spinyleg sightings, Boston has the highest daily chance: under 5%. Next come Montreal (Canada, under 5%) and Dallas (United States, under 5%).
GBIF citizen-science records
It is estimated from how often the Black-Shouldered Spinyleg is recorded against all the insects logged in Boston (37 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
