Cordulia aenea
In 3 days ~10% in a week ~20%
The downy emerald (Cordulia aenea) is a species of dragonfly. It is metallic green and bronze in color, and its thorax is coated with fine hairs, hence its name. Like most other emeralds, the downy emerald has bright shiny green eyes. Adults are around 5 cm (2.0 in) in length, and are in flight from May through July each year.
This species lives in woodlands near lakes and ponds; like other dragonflies, it lays eggs in water and its larvae are aquatic. It is distributed throughout most of Europe. Although it has been eliminated from some of its historic native area in Great Britain due to habitat loss, dense populations of the downy emerald can still be found there in spots where its ideal habitat remains.
After the downy emerald young emerge from their eggs, they live for three years at various larval and nymphal stages. They are fully grown adults for only two months, during which this time they mate and the females deposit their eggs back into the water. Female individuals of the Cordulia aenea (C. aenea) species have panoistic ovaries that produce female sex cells, or oocytes. The nucleus of the panoistic oocyte likely contains all the necessary genetic material to develop the oocyte on its own, form the C. aenea egg yolk, and develop the C. aenea embryo. Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Plitvice Lakes National Park | 🇭🇷 Croatia | |
| 2 | Biebrza National Park | 🇵🇱 Poland | |
| 3 | Mercantour National Park | 🇫🇷 France | |
| 4 | Triglav National Park | 🇸🇮 Slovenia | |
| 5 | Bavarian Forest National Park | 🇩🇪 Germany | |
| 6 | Pyrénées National Park | 🇫🇷 France | |
| 7 | Wadden Sea National Park | 🇩🇪 Germany |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Vienna | 🇦🇹 Austria | |
| 2 | Stockholm | 🇸🇪 Sweden | |
| 3 | Brussels | 🇧🇪 Belgium | |
| 4 | Moscow | 🇷🇺 Russia | |
| 5 | Kyiv | 🇺🇦 Ukraine | |
| 6 | Hamburg | 🇩🇪 Germany | |
| 7 | Copenhagen | 🇩🇰 Denmark | |
| 8 | Paris | 🇫🇷 France | |
| 9 | Nizhny Novgorod | 🇷🇺 Russia | |
| 10 | Helsinki | 🇫🇮 Finland |
Rare
Under 5% of wildlife watchers report a Downy Emerald sighting in Helsinki on a given day, based on 5 verified sightings from GBIF citizen-science data. It is the 732nd most-seen of the 838 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
June
In that month about 10% of wildlife watchers report a Downy Emerald in Helsinki on a given day, against under 5% in July to May, the lowest months.
Between 10 am and 1 pm
Across all the parks we cover, that three-hour window holds the most Downy Emerald sightings with a recorded time, and nearly all of them come between 6 am and 6 pm: it is a daytime animal.
10th of 12
Of the 12 cities where we can rate Downy Emerald sightings, Helsinki ranks 10th at under 5%. The best odds are in Vienna (Austria, about 10%), Stockholm (Sweden, about 10%) and Brussels (Belgium, about 10%).
GBIF citizen-science records
It is estimated from how often the Downy Emerald is recorded against all the insects logged in Helsinki (5 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.
