Sefton Coast Wildlife

Silver Y Moth

Autographa gamma

UK Green ListEasy to see📍 Ainsdale NNR
Season
May–October; migrant — can arrive in extraordinary numbers in some years.
Best time of day
Day and night — unusual in being active in both light and dark
Sefton Coast
Very common in most years; sometimes extremely abundant in mass migration events
UK population
Entirely migratory from North Africa and southern Europe; numbers vary enormously

Tap image to enlarge · Wikimedia Commons

Overview

The Silver Y is one of Britain's most important insects — a migrant moth that arrives in huge numbers from North Africa, breeds in Britain and creates a new generation that migrates south again in autumn. Numbers are staggering in good years — millions arrive in coordinated nocturnal migrations. The Y-shaped silver mark on the forewing is the key feature. It hovers at flowers by day as well as night, making it one of the most visible moths for non-moth-trappers.

At a Glance

OrderLepidoptera
FamilyNoctuidae
HabitatOpen dune grassland · Garden · Any habitat with flowers
DietAdults: many flowers — hovers while feeding. Larvae: clover, nettles, plantains, many low plants.
UK populationEntirely migratory from North Africa and southern Europe; numbers vary enormously
Sefton CoastVery common in most years; sometimes extremely abundant in mass migration events
ConservationUK Green List

Where to See It

Anywhere on the Sefton Coast in summer. Often seen hovering at flowers by day. Numbers can be extraordinary in good migration years.

Identification

Medium noctuid moth. Grey-brown forewing with a conspicuous silver Y (or gamma γ) shaped mark — unmistakeable. Hovers at flowers in daylight. In flight, white Y mark flashes.

Viewing & Photography Tips

Watch any flower patch on the dune grassland in August. Silver Ys hover to feed, making them easy to observe. In invasion years they're everywhere.

Conservation Status

UK Green List

This species has a favourable conservation status in the UK and remains an important part of Sefton Coast biodiversity.

Frequently Asked Questions

How many Silver Y Moths come to Britain each year?

In good years, hundreds of millions of Silver Ys arrive in Britain from the continent. Radar studies have revealed organised, wind-assisted nocturnal migrations of enormous scale — entire fronts of moths moving purposefully north and south between Britain and North Africa across multiple generations. It's one of the great wildlife spectacles of the insect world, largely invisible but tracked by radar.

Related Species

Plan your visit to the Sefton Coast

Marshside RSPB, Formby pinewoods, Ainsdale NNR — practical guides to getting there, what to bring, and the best spots for each season.