Simosyrphus grandicornis
In 3 days ~40% in a week ~70%
Simosyrphus grandicornis, commonly known as the yellow-shouldered stout hoverfly, is an Australasian species of hoverfly, and is one of the two most common hoverflies in Australia, alongside Melangyna viridiceps. It has been introduced to a number of Polynesian Islands as well as Hawaii.
Eggs are laid near aphid colonies, as the prey of this species' larvae is mainly aphids. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Grampians National Park | 🇦🇺 Australia | |
| 2 | Hattah-Kulkyne National Park | 🇦🇺 Australia | |
| 3 | Kosciuszko National Park | 🇦🇺 Australia | |
| 4 | Blue Mountains National Park | 🇦🇺 Australia | |
| 5 | Royal National Park | 🇦🇺 Australia | |
| 6 | Great Otway National Park | 🇦🇺 Australia |
Possible
About 20% of wildlife watchers report a Yellow-Shouldered Stout Hover Fly sighting in Hattah-Kulkyne National Park on a given day, based on 7 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 25th most-seen of the 61 insects we can rate there. Over three days the chance rises to about 40%, and over a week to about 70%, if each day is a fresh chance.
September
In that month about 30% of wildlife watchers report a Yellow-Shouldered Stout Hover Fly in Hattah-Kulkyne National Park on a given day, against under 5% in May–August and November–March, the lowest months.
Between noon and 3 pm
Across all the parks we cover, that three-hour window holds the most Yellow-Shouldered Stout Hover Fly sightings with a recorded time, and about 8 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
Among the best
Of the 6 parks where we can rate Yellow-Shouldered Stout Hover Fly sightings, Hattah-Kulkyne National Park ranks 2nd at about 20%, level with the leaders once rounded. The best odds are in Grampians National Park (Australia, about 20%).
GBIF citizen-science records
It is estimated from how often the Yellow-Shouldered Stout Hover Fly is recorded against all the insects logged in Hattah-Kulkyne National Park (7 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.
