Simosyrphus grandicornis
In 3 days ~20% in a week ~50%
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 |
With luck
About 10% of wildlife watchers report a Yellow-Shouldered Stout Hover Fly sighting in Kosciuszko National Park on a given day, based on 5 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 85th most-seen of the 105 insects we can rate there. Over three days the chance rises to about 20%, and over a week to about 50%, if each day is a fresh chance.
October
In that month about 20% of wildlife watchers report a Yellow-Shouldered Stout Hover Fly in Kosciuszko National Park on a given day, against under 5% in March–September and November, 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.
3rd of 6
Of the 6 parks where we can rate Yellow-Shouldered Stout Hover Fly sightings, Kosciuszko National Park ranks 3rd at about 10%. The best odds are in Grampians National Park (Australia, about 20%) and Hattah-Kulkyne 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 Kosciuszko National Park (5 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.
