Species Account

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Distribution


 
 

Summary Data


Season (Adult / Immature):

National Status: Migrant

Local Status: Scarce to common migrant.

Local Record: Grade 3   See here for explanation

Flight time: Recorded all year, mainly Jun-Oct.

Forewing: 13-14mm.

Foodplant: Dandelion, Groundsel, docks, Common Restharrow.

IMPORTANT - Please note that the maps and accounts are provisional, subject to change and further update.  The whole dataset still needs to go through the final verification process and it is likely that a very small number of records will not satisfy the present requirements and there are other records that have not been formally submitted.  The information is for guidance only.

Record breakdown:

 VC9VC11Region
Year first recorded190519851905
Year last recorded201120092011
Number of records1032222108
Number of individuals3718187472
Unique positions1337280
Unique locations1076226
Adult records1020172074
Immature records000

For the region, we have a total of 2108 records from 226 sites. Earliest record on file is in 1905.
 

Photos


2385 Small Mottled Willow 03
© Will Bown, November 2015
2385 Small Mottled Willow 02
© Gillian Nash, June 2015
2385 Small Mottled Willow 01
© Tom Morris

Species Account


For further information refer UK Moths.

Davey, P., 2009: A strongly migratory species with a near-global tropical and sub-tropical distribution that ranges from a virtual annual in southern England to a relative rarity in northern Scotland. The larva is a pest of crops in regions south of 35 deg. N. In Dorset, the moth has been recorded with increasing frequency since 1982, but very few in the very westerly El Nino summers of 2007 and 2008, and in every month apart from December and March. In favourable seasons, immigrants spawn resident populations, as happened in 1906, 1996, 2003 and 2006. "1906 will be memorable for the sudden appearance, at the end of May and the beginning of June, of considerable numbers of several different kinds of Lepidoptera, some of which are usually very rare in Britain, being unable to survive our winters. The species that thus appeared, having doubtless flown over from the continent, were Painted Lady, Striped Hawk, Bordered Straw, Silver Y, Nomophila noctuella and Plutella xylostella, and there is every reason for believing that a flight of Small Mottled Willow, reached Dorset at the same time. The summer being favourable to their progeny, large subsequent broods of most of these welcome visitors was observed in due course." (Reverend E Bankes).

A similar massive immigration, featuring all of the species mentioned in the Bankes account occurred in the middle of June 1996, often with large numbers recorded. The respective weather maps for the two events show south to south-westerly airflows originating from low latitudes on both occasions. In 2003, two-hundred and ninety-three moths appeared on Portland between 14 and 16 June, and a similar total of two-hundred and twenty were trapped there in the remarkable winter immigration of 2004, between the 11 and 13 February. Southerly airflows likely transported huge numbers of these moths on each occasion from the region of the Sahara. The main brood peaks are roughly fifty days apart, on average. The species does not appear to be able to survive the UK winter in any stage, so although in excess of one thousand moths were recorded in both 1996 and in 2006, a grand total of just one moth was seen in the two seasons that followed.
 

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