Stigmella hemargyrella
In 3 days ~10% in a week ~20%
Stigmella hemargyrella is a moth of the family Nepticulidae. It is found in most of Europe, except Iceland, Norway, Finland, Portugal and most of the Baltic region. The wingspan is 5–6 mm. The head is light ochreous-yellowish. The antennal eyecaps are whitish. The forewings are deep shining bronzy with a golden-tinged silvery-metallic hardly oblique fascia at 2/3.The apical area beyond this is dark purple-fuscous. The cilia round apex beyond a blackish median line are white. The hindwings are rather dark grey.
The moths (imago) are bivoltine flying from April to May and again from July to August and can be found resting on trunks. The egg can be laid on either side of the leaf and the pale yellowish-white larva feed, within a mine on Fagus sylvatica and Fagus sylvatica orientalis. The mine is a sinuous gallery and at the early state is relatively narrow with a central line of dark frass. As the larva grow the mine becomes wider and in the middle portion the frass is arranged in a series of arcs or coils. The mine can cross the vein (compare Stigmella tityrella which rarely crosses the veins) and in the final stages of the mine the frass is more irregular and concentrated in the centre of the gallery. Wikipedia →
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More parks will be added in future updates.
Rare
Under 5% of wildlife watchers report a Beech Pigmy sighting in London on a given day, based on 6 verified sightings from GBIF citizen-science data. It is the 1394th most-seen of the 1504 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.
November
In that month about 10% of wildlife watchers report a Beech Pigmy in London on a given day, against under 5% in December to October, the lowest months.
2nd of 2
Of the 2 cities where we can rate Beech Pigmy sightings, London ranks 2nd at under 5%. The best odds are in Liverpool (United Kingdom, about 10%).
Same genus: Stigmella
The closest relatives of the Beech Pigmy that you can see in London (genus Stigmella) are Golden Pigmy (about 10%) and Scarce Maple Pigmy (about 10%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Beech Pigmy is recorded against all the insects logged in London (6 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.
