Simosyrphus grandicornis
In 3 days ~50% in a week ~80%
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 Grampians National Park on a given day, based on 29 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 33rd most-seen of the 148 insects we can rate there. Over three days the chance rises to about 50%, and over a week to about 80%, if each day is a fresh chance.
October to December
In those months about 30% of wildlife watchers report a Yellow-Shouldered Stout Hover Fly in Grampians National Park on a given day, against under 5% in January to August, 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.
Yes
Of the 6 parks where we can rate Yellow-Shouldered Stout Hover Fly sightings, Grampians National Park has the highest daily chance: about 20%. Next come Hattah-Kulkyne National Park (Australia, about 20%) and Kosciuszko National Park (Australia, about 10%).
Same family: Syrphidae
The closest relatives of the Yellow-Shouldered Stout Hover Fly that you can see in Grampians National Park (family Syrphidae, Hover Flies) are Common Halfband (about 20%), Native Drone Fly (about 10%) and Common Drone Fly (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Yellow-Shouldered Stout Hover Fly is recorded against all the insects logged in Grampians National Park (29 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.
