RECORDS NOTEBOOK

Containing this issue: 
 
COMMON HAWKER IN SUFFOLK 2007 ~ by Ricky Fairhead
BARN OWL PELLETS FROM ORFORD NESS ~ by Stuart Warrington
THE LARGE GARDEN BUMBLEBEE IN SUFFOLK ~ by Adrian Knowles
2007 UPDATE ON THE BROWN HARE POPULATION AT ORFORD NESS by Stuart Warrington
RHACOGNATHUS PUNCTATUS (L), AN UNDER RECORDED SHIELD BUG ~ by Nigel Cuming

COMMON HAWKER IN SUFFOLK 2007

On July 28th 2007, I was walking with Debbie Franklin at Burgh Castle, TG4604, when we saw a large hawker fly by and land on a nearby bush. The strikingly yellow costa, broad eye contact and large size made me suspect that this was a Common Hawker, although I really needed to try and get a photo as confirmation, as I knew that this was an important record and would be a county first. Fortunately I had my camera with me, and managed to get one acceptable shot, a closer approach moments later was not as successful as the hawker instantly flew off (photo below).

Common Hawker was recently removed from the county list as all previously claimed records are now thought to be misidentified Migrant Hawkers. Over the border in Norfolk the Common Hawker is still fairly numerous in the Winterton area, which is the most likely origin of this individual. Thanks to Adrian Parr and Keith Morris for commenting on this record, and confirming the identification.

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BARN OWL PELLETS FROM ORFORD NESS

Each year between one and three pairs of barn owls nest at Orford Ness. They use the buildings on site as nesting sites, which means that their pellets are easily collected. For several years pellets from there have been sent to The Mammal Society for use in their ‘owl pellet prey identification’ training events, but in the last three years, a group of volunteers has collected and studied the pellets on site during a working holiday.

The examination of 43 barn owl pellets collected in June 2007 revealed the remains of 137 small mammals (average of 2.81 prey per pellet in 2007, compared with 2.95 in 2006). The maximum number of prey found in one pellet was 8 (4 field voles, 3 pigmy shrews, 1 common shrew). There were 5 field voles in 2 pellets, and 4 prey occurred in 11 pellets.

In common with all previous years, field voles were the dominant prey of the barn owls at Orford Ness. In June 2007, 98% of the pellets contained field vole remains, and these voles made up 88% of the prey (up from 75% of the prey in June 2006). Common and pigmy shrews were the next most common prey found in about 10% of pellets, but both amounted to less than 5% of the barn owl prey items. Other small mammal species found in fewer than 5% of the pellets in 2006 and 2007 were water vole, bank vole, water shrew, wood mouse, house mouse, rabbit and brown rat. Rabbits are very infrequently taken by barn owls at Orford Ness, with the remains of just one juvenile found in one pellet out of the 200 or so examined in the last five years. Surveys for water voles at Orford Ness have revealed that this declining species is actually doing very well in the brackish ditches in the marshes, with lots of latrines and burrows in evidence. It is not surprising therefore that the barn owls have caught some of these, although the numbers are low, with remains of only four water vole being found in the 70 pellets examined in 2006 and 2007.

The examination of owl pellets gives a good indication of what these birds are feeding on and the year-to-year changes if data are collected regularly. It also provides some information on small mammal occurrence in the area, although the owls may fly some distance to find prey; thus some prey might not be taken on site. The barn owls at Orford Ness seem to be doing well in 2007, and at the end of June one pair had fledged three offspring and another appeared to have two juveniles ready to leave the nest.

Stuart Warrington, The National Trust

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THE LARGE GARDEN BUMBLEBEE IN SUFFOLK

The Large Garden Bumblebee, Bombus ruderatus, is one of the rarer British bumblebees. It is the subject of a UK Biodiversity Action Plan aimed at reversing its seemingly inexorable trend from being a reasonably widespread if localised species of lowland England prior to the 1960s to a species threatened with extinction ten or so years ago. It was recorded by Claude Morley (as Bombus hortorum var. subterraneus) but modern records are, in keeping with national trends, precious few. Heather Paxman recorded it around Woodbridge in 1993 and Ted Benton took a specimen from Icklingham in 2005.

During this summer I have recorded two males from Maidscross Hill near Lakenheath; one the typical form, which very closely resembles the very common Small Garden Bumblebee Bombus hortorum, with the other being the striking all-black form (known to Morley as B. hortorum var. harisellus). The species appears to forage on a variety of long-flowered plants, including Comfrey, Marsh Woundwort, Rosebay Willowherb and also Red Clover. Simple arable field margins sown with Red Clover as conservation headlands may be a significant factor in the reversal of fortunes of this species. In the last 3-4 years an increasing number of records of this bumblebee have been made in Essex and it is hoped that this trend may continue in Suffolk.

This bee is not easy to separate from the very common Bombus hortorum, with both species typically being black with three yellow hair bands and a white “tail” or tip to the abdomen. Key factors in identification are that the two yellow bands on the thorax (middle part of the body) are of equal width and the yellow band on the abdomen is restricted to the first segment. The males have a gingery-brown “beard” of hairs on the underside of the mandibles, as opposed to black hairs on those of B. hortorum. Whilst all-black male hortorum are said to occur, this more obvious colour pattern is more likely to be that of a melanic B. ruderatus.

Adrian Knowles
Hymenoptera Recorder

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2007 UPDATE ON THE BROWN HARE POPULATION
AT ORFORD NESS

A review of the brown hare at Orford Ness in the Society’s journal in 2006 (Suffolk Natural History 42: 31-36) revealed that there was a strong population on this site, but that numbers had dropped significantly between 2005 and 2006. A re-survey was carried out in June 2007 to see how the population had fared, using a team of volunteers to carry out a ‘walk-over’ survey of the whole 770 hectare site. The results show that the population had declined again to about one third of the numbers seen in June 2005. The favoured areas of the property were once again sites E (the shingle areas from around the laboratory buildings to north of the lighthouse) and F (Orford Beach, south of Havergate Island).

It was noted in 2007 that no juvenile hares were spotted which suggests that the cold and wet May had affected breeding. There was plenty of vegetation and the grasses had grown so well that it is possible that some hares were missed in the 2007 survey if they had stayed down in the vegetation as the survey team passed by. Brown hares often have three (or even four) litters in a summer, so that if June and July are warmer, they may yet successfully rear leverets. We do hope that the weather relents and allows the brown hare to bounce back on the Ness.

Table 1. Observations of Brown Hares at Orford Ness in each area of the site 2005 to 2007
(See Suffolk Natural History vol. 42 for a map and description of the sites)

Site	June 2005 Number	June 2006 Number	June 2007 Number
A	10	2	0
B	8	6	2
C	5	2	1
D	5	2	2
E	21	6	11
F	36	24	11
G	17	4	5
Total	102	46	32
Density (no. per km2)	11.7	5.3	3.7

Stuart Warrington, The National Trust.
stuart.warrington AT nationaltrust.org.uk

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RHACOGNATHUS PUNCTATUS (L)
AN UNDER RECORDED SHIELD BUG ON SUFFOLK HEATH LAND

I was visiting Dunwich Heath on the fifth of April this year, in the area adjacent to Minsmere North marsh, at approximately TM 469680, and found a specimen of Rhacognathus punctatus on the footpath.

This very variable Hemipteran is known to be predatory upon the Heather Beetle (Lochmaea suturalis) and the closely related Lochmaea capreae, which may be found feeding on the leaves of Sallow. Another “leaf beetle” Chrysolina brunsvicensis is known but I have not yet found the latter in this area of the county, although the marshy habitat at Docwra’s ditch does seem suitable for it. The Heather Beetle was extremely abundant last year, and seems to be again this year so there is no shortage of prey for the bug to feed upon. Having mentioned that this species is variable, a short description will not go amiss - length 7-9mm, coloration usually bluish green with a metallic bronze lustre, overlaying a slightly orange-red background. Despite the variability there are two characteristics that enable the bug to be identified - to a greater or lesser degree there is a reddish line down the centre of the thorax and on all the tibiae there is always an orange- red band.

Whilst looking through the list of Suffolk records that Martin Sanford had given me, I was surprised to note the relatively few records for the county of this species. The earliest record I have is from Elvedon, 1903-1904, by Mr Harwood. Ted Ellis recorded it from three Suffolk localities, Dunwich, Walberswick and Covehithe on 31-08-1949. J.M.Campbell found it on Westleton heath, 18-08-1986, and the most recent record, prior to my find, was by an anonymous observer, at Martlesham Heath in 1988.

I hope that this small snippet may encourage Suffolk naturalists to be more aware of the Hemiptera of the county; they do make splendid subjects for digital photography, and I would be very pleased to assist in any queries regarding identification.

Acknowledgements
Martin Sanford, SBRC for his help with records.
National Trust, Dunwich Heath, and David Sutton, Warden for access to site and help.

References
Southwood T.R.E. & Leston D. Land and water Bugs of the British Isles. Warne & Co. Ltd. 1959.

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