Simosyrphus grandicornis
In 3 days ~40% in a week ~60%
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 Perth on a given day, based on 93 verified sightings from GBIF citizen-science data. It is the 20th most-seen of the 275 insects we can rate there. Over three days the chance rises to about 40%, and over a week to about 60%, if each day is a fresh chance.
November
In that month about 30% of wildlife watchers report a Yellow-Shouldered Stout Hover Fly in Perth on a given day, against under 5% in March and June–August, the lowest months. That is one of Perth's driest months, with about 25 mm of rain against 130 mm in July.
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 5 cities where we can rate Yellow-Shouldered Stout Hover Fly sightings, Perth ranks 2nd at about 10%, level with the leaders once rounded. The best odds are in Melbourne (Australia, about 10%).
GBIF citizen-science records
It is estimated from how often the Yellow-Shouldered Stout Hover Fly is recorded against all the insects logged in Perth (93 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.
