Hamamelistes spinosus
In 3 days ~10% in a week ~30%
Hamamelistes spinosus, also known as the spiny witch-hazel gall aphid, is a species of aphid that creates galls on witch hazel and birch species. Its eggs are laid on Witch Hazel in galls, where they overwinter and hatch in spring.
They manipulate and live in leaves on birch, with nymphs eating leaves then overwintering on stems. Their life cycles tend to last around 2 years. They create galls by feeding on leaf buds in a way that forms them to support their young.
Hamamelistes spinosus is found across North America, from Mexico to Canada. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Shenandoah National Park | 🇺🇸 United States |
More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Boston | 🇺🇸 United States | |
| 2 | New York City | 🇺🇸 United States | |
| 3 | Washington | 🇺🇸 United States | |
| 4 | Philadelphia | 🇺🇸 United States | |
| 5 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 6 | Chicago | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report a Spiny Witch-Hazel Gall Aphid sighting in Shenandoah National Park on a given day, based on 6 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 571st most-seen of the 723 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.
August and October
In those months about 10% of wildlife watchers report a Spiny Witch-Hazel Gall Aphid in Shenandoah National Park on a given day, against under 5% in September and November–July, the lowest months.
Between 3 and 6 pm
Across all the parks we cover, that three-hour window holds the most Spiny Witch-Hazel Gall Aphid sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
Only Shenandoah National Park, in our data
Shenandoah National Park is the only park on Wallace's Line with enough records to rate Spiny Witch-Hazel Gall Aphid sightings: under 5% of wildlife watchers there report one on a given day.
Same family: Aphididae
The closest relatives of the Spiny Witch-Hazel Gall Aphid that you can see in Shenandoah National Park (family Aphididae, Aphids) are Witch-Hazel Cone Gall Aphid (about 10%), Oleander Aphid (about 10%) and Giant Bark Aphid (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Spiny Witch-Hazel Gall Aphid is recorded against all the insects logged in Shenandoah National Park (6 verified sightings from 2019 to 2026), 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.
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