Moth News: Quality migrants make the headlines and there’s good news for rare breeders

The second half of August was fairly settled, often with dry, cloudy nights but temperatures never particularly high. A couple of rather short spells of muggy conditions around the month's end, and again from 8th September, did give us a brief taste of what is possible in late summer, but these were short-lived and blown away by periods of very strong westerly winds. A few quality iconic moths made up for the lack of real numbers.

A Portland Moth at Kilnsea (East Yorkshire) on 15th August was only the third for the Spurn peninsula and was followed by another east-coast specimen at Weybourne (Norfolk) on 9th September. These two are almost certainly of continental origin, as the species has declined greatly as a breeder and its main British stronghold is now on the west coast, in Lancashire. A single Jersey Mocha was at Bonchurch (Isle of Wight) on 19th August and the next night a Plumed Fan-foot was at Winchelsea (East Sussex). On the Channel Islands a good contender for Idaea corrivalaria was photographed on Alderney on 20th. This continental geometrid has never been recorded in Britain, but this individual so far awaits verification.

The Weymouth area of Dorset scored heavily on the night of 22nd when a Pine-tree Lappet was caught at Portland Bill coastguards by visiting Bernard Skinner. This first for Dorset was quickly given a home at the nearby bird observatory, where it could be admired more easily. The continental populations of this moth appear to have longer flight periods than our resident Scottish ones.

Pine-tree Lappet at Portland Bill, August 2011 (Martin Cade).

Nearby at West Bexington, county micro-recorder Phil Sterling was equally pleased to find the county's third Rosy Underwing. Breeding as close as the Channel Islands, this large colourful flat noctuid is still very rare in the UK.

Rosy Underwing at West Bexington, August 2011 (Phil Sterling).

Also on the 22nd, a Dark Crimson Underwing was at Bonchurch (Isle of Wight) but elsewhere migrants were surprisingly thin in the trap. Out on the Sefton Coast of Lancashire by day on the 25th August, Rod Hill was extremely fortunate to discover a Crimson Speckled nectaring on Bramble flowers at Formby Sands NR. Next day several recorders hunted high and low for the insect but to no avail. Another Crimson Speckled was reported near Porthgwarra (Cornwall), 9th September.

Crimson Speckled on Bramble, Formby (Lancs), 25th August 2011 (Rod Hill).

Well inland at Abberton (Worcestershire), a Dotted Rustic came to a garden trap overnight on 25th August and was the first county record since 1989! This rare resident, which in the past has experienced large fluctuations in population, is currently seldom seen, despite its habit of mid-summer hibernation in outbuildings and garden sheds. Most recent national records are from or near the coast, suggesting that it may, at this moment in time, occur only as a migrant. Dungeness Bird Observatory warden Dave Walker received acclaim, for the second time this summer, when he found an irresistible Beautiful Marbled on the wall by one of his garden traps on the morning of 30th. This small but stunning moth was only recorded for the first time in the UK in 2001 but since then three minor influxes and a few singles have produced over 20 records. This was the first for the Dungeness area and the third Kent record.

Beautiful Marbled, Dungeness (Kent), 30th August 2011 (Dave Walker).

While out shopping in Lymington (Hants), a young lady was amazed to spot a live Death's Head Hawkmoth on the ground under a building society's front window on 7th September. She attempted to 'save' it by placing it a short distance away from the busy thoroughfare, but was dismayed to find it had gone when she returned a few minutes later with a hurriedly purchased pot.

Conditions on the evening of 8th improved greatly and overnight an encouraging cast of commoner migrants had arrived at Berry Head (Devon). However, who would have predicted that one of the best moths of the whole summer would turn up in the leafy suburbs of northeast London the next night. Forty years of trapping in his Woodford Green garden has been a large part of Robin Barfoot's life. His major reward was Britain's second ever Dorset Cream Wave on 2nd July 2006. Not as rare but much more impressive was the virtually pristine Passenger secured just before dawn there on the 10th. A few days earlier, Robin had nearly thrown the towel in for the season due to big problems from early-morning avian visitors attempting to get a 'full breakfast' from the contents of his trap. Luckily he decided to give it one more go and got up before the birds, just in case something special had come in — another example of how great moths can occur virtually anywhere in the country.

The Passenger, Woodford Green (Essex), 10th September 2011 (Robin Barfoot).

The Gloucester Moth Group had their annual late-summer survey at Slimbridge WC on 26th August and sadly got a real drenching. The one bright spark to light was the attractive micro Tebenna micalsis (386), a rare migrant which occasionally stays to breed on Fleabane. A Mung Moth came to light at Littlehampton (East Sussex) on 2nd September. Although it may have possibly been imported from the Tropics with leguminous vegetables, it could also have been 'funnelled in' on the same warm air that brought the Beautiful Marbled to neighbouring Kent and so must be a candidate for a true vagrant. Other scarce 'micro' migrants included two more Cydia amplana, an Evergestis limbata, three Palpita vitrealis and two Conobathra tumidana. The regular migrant pyralid Rusty-dot Pearl had a good show with double figures at many southern sites and an impressive count of 120 at Berry Head (Devon) on the 8th.

Although numbers of other regular macro migrants was a little disappointing, there was a wide scattering of records with some species getting well inland. Totals included minimum seven Portland Ribbon Wave, 11 Vestal, three Gem, 27 Convolvulus Hawkmoth, 11 Pearly Underwing, 12 Delicate, three White-speck, 24 Small Mottled Willow, seven Scarce Bordered Straw, two Bordered Straw and 15 Ni Moth. A small influx of 'continental' Latticed Heath included eight at Bawdsey (Suffolk) on 9th September. Good numbers of Hummingbird Hawkmoth, Dark Sword-grass and Silver Y were recorded.

Vestal at Little Hereford (Herefordshire), 21st August 2011 (John Abbiss).

Small Mottled Willow at Norchard (Worcs), 9th September 2011 (Steve Whitehouse).

Migrant butterflies were poorly represented, with just 10 Clouded Yellows and small numbers of Painted Ladies.

One migrant species that has again become a transitory resident is the wonderful Clifden Nonpareil or Blue Underwing. Recent records suggest that it is now breeding in the New Forest (Hants), along the River Frome valley in Dorset and in parts of West Sussex. An early one was at Brockenhurst (Hants) on 23rd August and it was followed by further singles at Puddletown (Dorset) on 8th September, Holbury (Hants) on the 9th and Southsea (Hants) the next day. Its larvae feed on Aspen and Poplar and the adults come to sugar and wine ropes as well as to light traps.

Clifden Nonpareil and Light Crimson Underwing together at Brockenhurst (Hants), 24th August 2011 (Russell Wynn).

A male Gypsy Moth was found in southwest London on 25th August and no doubt is part of the scattered breeding population within the capital. It has also been found in at least two other areas of England in the last few years. The creamy white females are flightless and rarely seen.

Male Gypsy Moth (Steve Whitehouse).

Butterbur is another difficult-to-see moth. It is rather local in southern England and even if actinic lights are placed right amongst the same-name food-plant you cannot guarantee success. It is more abundant north of Manchester, either side of the Pennines along narrower watercourses and overgrown streams. Singles at light in Northumberland at Howick on 18th and Tynemouth on 20th August and at Mill House (Lancs) on 30th are no doubt evidence for a good season in the north.

Butterbur at Howick (Northumbs), August 2011 (Stewart Sexton).

The Marsh Mallow Moth is a red data resident at a handful of sites in Kent and East Sussex. As its name suggests, its range is confined to where the food-plant is found, but only in southeast England. This autumn a new colony has been discovered in North Kent and it is also still thriving at another known colony where the habitat is protected. So often we hear of rare moths 'in trouble' and declining further so this time it's good news all round.

Marsh Mallow Moth (Kent), September 2011 (Steve Whitehouse).

Other interesting finds in this period included only the second ever Brindled Ochre on the Staffordshire Moors on 9th September, where on the same night a colony of the upland tortrix Acleris caledoniana was discovered – and this was a county first! A late Dentated Pug was found at Flowers Green (East Sussex) on 10th September and on the same night the earliest ever Streak was recorded in Hampshire.

Finally, small numbers of Small Marbled larvae, hatched from eggs laid by migrant adults in July, have now been successfully reared through to adults, to reveal that nearly all are the highly distinctive dark-banded form. It will be interesting to see whether any wild-born adults from this second generation are found in the next few weeks.

Reared second-generation Small Marbled at Wyke Regis (Dorset), August 2011 (Dave Foot).