Summer Chafer

Summer Chafer

Amphimallon solstitiale

Daily sighting probability ~10% · With luck
at Triglav National Park

In 3 days ~40% in a week ~60%

12 Verified sightings at Triglav National Park From 2019 to 2026
28 In all 2 parks
July Best month
☀️🌙 Day & Night When it's spotted

About the Summer Chafer

Amphimallon solstitiale, also known as the summer chafer or European june beetle, is a beetle similar to the cockchafer but much smaller, approximately 20 millimetres (0.79 in) in length. They are declining in numbers now, but where found they are often seen in large numbers. At dusk they actively fly around tree tops looking for a mate and can often be found drowning in pools of water the following morning. They are also attracted to light and come in through open, lit windows and fly around lamps, making quite a racket while bumping into lights. They are found throughout the Palearctic region (and North America) and, commonly seen from June to August, living in meadows, hedgerows, and gardens, and eating plants and tree foliage.

The larva of summer chafer undergo a two to three-year period of development underground, feeding upon host plants. Carabid beetles, such as Poecilus cupreus, hunt and consume larvae and serve as a primary predator in arable fields.

These June beetles act as root pests for a number of economically important crops including potatoes, rape, legumes, chestnuts, and turfgrass. As generalist herbivores, they primarily feed upon secondary roots with smaller amounts of anti-herbivore chemicals across many different species. Several chemical and bio-control agents have been developed to control their populations, including their endemic bacteria and entomopathogenic nematodes. Wikipedia →

Global Distribution

Parks Where Found

# Park Country Daily sighting probability
1 Triglav National Park 🇸🇮 Slovenia
~10%
2 Bavarian Forest National Park 🇩🇪 Germany
~10%

Cities Where Found

# City Country Daily sighting probability
1 Copenhagen 🇩🇰 Denmark
~20%
2 Minsk 🇧🇾 Belarus
~10%
3 Kyiv 🇺🇦 Ukraine
~10%
4 Warsaw 🇵🇱 Poland
~10%
5 London 🇬🇧 United Kingdom
~10%
6 Prague 🇨🇿 Czechia
~10%
7 Berlin 🇩🇪 Germany
~10%
8 Birmingham 🇬🇧 United Kingdom
~10%
9 Helsinki 🇫🇮 Finland
~10%
10 Hamburg 🇩🇪 Germany
~10%

Before you go

What are the chances of seeing a Summer Chafer in Triglav National Park?

With luck

About 10% of wildlife watchers report a Summer Chafer sighting in Triglav National Park on a given day, based on 12 verified sightings from GBIF citizen-science data from 2019 to 2026. It is the 126th most-seen of the 260 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.

When is the best time to see a Summer Chafer in Triglav National Park?

July

In that month about 30% of wildlife watchers report a Summer Chafer in Triglav National Park on a given day, against under 5% in September to May, the lowest months.

What time of day is best to see a Summer Chafer?

Between 8 and 11 pm

Across all the parks we cover, that three-hour window holds the most Summer Chafer sightings with a recorded time, and about 6 in 10 of them come between 6 pm and 6 am: it is seen both by day and at night.

Is Triglav National Park the best place to see a Summer Chafer?

Yes

Of the 2 parks where we can rate Summer Chafer sightings, Triglav National Park has the highest daily chance: about 10%. Next come Bavarian Forest National Park (Germany, about 10%).

Where does the Summer Chafer sighting chance come from?

GBIF citizen-science records

It is estimated from how often the Summer Chafer is recorded against all the insects logged in Triglav National Park (12 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.

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