Ceratomia amyntor
In 3 days ~10% in a week ~30%
Ceratomia amyntor, the elm sphinx or four-horned sphinx, is a North American moth in the family Sphingidae. The species was first described by Carl Geyer in 1835. It has a wingspan of 3+1⁄4-4+1⁄2 inches (8.2 - 11.5 cm). As the name suggests, the larvae (caterpillars) feed on elm trees (Ulmus), but they can also be found feeding on birch (Betula), basswood (Tilia), and cherry (Prunus). When the caterpillars are ready, they crawl to the bottom of the host tree, where they crawl underneath the soil and pupate and may overwinter underground if late enough into the year.
C. amyntor can be found from Nova Scotia west to Alberta and western North Dakota and Colorado; south Florida reaching into the Gulf Coast, Georgia, Texas, Louisiana and New Mexico. The species is not threatened. C. amyntor adults fly as a single brood in the northern portions of their range from June to July. There are two broods further south, flying later into the year, and five broods have been confirmed in Louisiana from March to October.
Tiny, translucent, lime-green eggs deposited on the underside of host leaves. The shells are transparent and pearly after hatching... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Great Smoky Mountains National Park | 🇺🇸 United States | |
| 2 | Shenandoah National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Chicago | 🇺🇸 United States | |
| 2 | Minneapolis [Saint Paul] | 🇺🇸 United States | |
| 3 | Boston | 🇺🇸 United States | |
| 4 | Montreal | 🇨🇦 Canada | |
| 5 | Austin | 🇺🇸 United States | |
| 6 | Baltimore | 🇺🇸 United States | |
| 7 | Dallas | 🇺🇸 United States | |
| 8 | New York City | 🇺🇸 United States | |
| 9 | Philadelphia | 🇺🇸 United States | |
| 10 | Washington | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report an Elm Sphinx sighting in Boston on a given day, based on 32 verified sightings from GBIF citizen-science data. It is the 360th 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 an Elm Sphinx in Boston on a given day, against under 5% in September to June, the lowest months.
Between 9 pm and midnight
Across all the parks we cover, that three-hour window holds the most Elm Sphinx sightings with a recorded time, and about half of them come between 6 am and 6 pm: it is seen both by day and at night.
Among the best
Of the 13 cities where we can rate Elm Sphinx sightings, Boston ranks 3rd at under 5%, level with the leaders once rounded. The best odds are in Chicago (United States, under 5%) and Minneapolis [Saint Paul] (United States, under 5%).
GBIF citizen-science records
It is estimated from how often the Elm Sphinx is recorded against all the insects logged in Boston (32 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.
