Autumn is a very exciting time for ‘twitchers’ when many birds are on the move with the changing season and there is an increased chance of something rare turning up on our shores. But it is not only birds that migrate: many insects do too! This autumn, for instance, has been a good one for migrant moths at Rye Harbour, with a range species, both common and uncommon and one or two new species for us as well.
Some of the species which arrive on our shores as migrants from the continent, such as large yellow underwing and angle shades, are also common resident breeding species in the UK. Another species which falls into this category is the diamond-back moth, a micro which has been known to travel over 3000km on migration and can arrive in the UK in their millions during the summer and autumn. However, the majority of migrant species that arrive in the UK do not live here permanently. Some are mainly migratory but can occasionally form breeding populations. Examples of these species trapped at Rye Harbour this autumn included l-album wainscot and white-point and during October also we had our first record of Italian tubic, a tiny moth first recorded in the UK in 2003 and now thought to have established a breeding population. Some of these species, such as the familiar silver y and humming-bird hawkmoth, despite being able to breed here, are unable to survive the winter (though silver y at least can still occur as a migrant at this time of the year). It’s likely that as our weather gets warmer this will change and life will probably get a lot easier for many species which currently only form transient populations.
The most sought after species are those which only turn up in the UK as very occasional migrants. This autumn it has included maize moth (above) and radford’s flame shoulder, this latter another new species for the reserve, both species of southern Europe which only ever reach our shores in relatively small numbers and have not yet managed to breed. In the past Rye Harbour has had some even rarer visitors. In July 1995, the then warden Dominic Funnell trapped a streaked plusia, a moth normally found in Africa and the Middle-East, which was not only the first British record, but a first for Europe too.
As well as natural migrants, some species have arrived on our shores through the actions of humans. One such species trapped recently, the London dowd (below), a micro moth which is native to Madeira, was introduced in 1946 and is now spreading in the UK. Another, perhaps less welcome, introduction is another micro the light brown apple moth which was imported from Australia in the 1930s, now common and widespread in southern Britain and has reached as far as the north of Scotland. Larvae of this species feed on a wide range of plants, and it can be a serious pest of fruit trees in some areas.