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THE BROWN HARE POPULATION AT ORFORD NESS IN JUNE 2005 AND 2006 STUART WARRINGTON AND DAVID CORMACK The Brown Hare (Lepus europaeus Linnaeus) originated from the steppes of central Asia and they probably spread west across Europe as forest was cleared for farming in the Neolithic period. They did not appear in Britain until the late bronze age (Tapper & Parsons, 1984).

The Brown Hare is a familiar site in the fields of East Anglia, but there are concerns about the long-term trends in their population, especially in the north and west of Britain. Hutchings and Harris (1996) examined various sources of records, including game bag returns, and reported that there appeared to be a widespread steady decline in Brown Hare numbers from the 1960s, but that numbers were more stable since the 1980s. However, the 1980s population was estimated to be under 20% of that present 100 years ago. This decline since the late 1880s was also noted by G. T. Rope, in the Victoria County History of Suffolk, who wrote in 1911 that Brown Hares were ‘common but not so abundant as they were 30 or 40 years ago.’ All the evidence points to the main factors in the population decline being the changes to the pattern of landscape management, especially the loss of rotational farming and the moves towards larger fields and less crop diversity (Game Conservancy, 2004).

Hutchings and Harris (1996) co-ordinated a survey of Brown Hares in the winters of 1991/92 and 1992/93, based on volunteers carrying out a walk-over survey of several hundred one kilometre squares spread across Britain. In summary, they found that predominately arable areas held the highest hare densities with an average 6 per km2. Pastoral areas had an average density of 3·5 per km2. The hares showed a preference for habitats of winter cereals, stubble and ploughed fields, followed by unimproved grasslands and shortterm grassland leys. The counties of Cambridgeshire, Norfolk and Suffolk were the stronghold of the Brown Hare, with nearly 20% of the UK population in just 5·1% of the UK land area. The total British population of Brown Hares was estimated to be between 817,500 and 1,250,000.

Due to the decline in Brown Hare numbers, the species was made a priority for conservation action in the first round of Species Action Plans (UK BAP, 2001). The main factors causing the species decline were listed as the loss of habitat diversity in the agricultural landscape, conversion of grassland to arable, and changes in cropping regimes, especially the move to winter cereals and silage. The UK action plan targets were to maintain existing populations and aim to double spring numbers by 2010. The local Suffolk Biodiversity Action Plan also included Brown Hare as a target species (Suffolk BAP, 2003).

Brown Hares have been frequently observed at Orford Ness since the National Trust took over the site in 1993. They have been seen all over the site, from the grazing marshes to the vegetated shingle and along the shingle spit, however, it was not known what the current population size might be.

There had been a previous, and more detailed, study of Brown Hares on

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Figure 1. The seven areas of Orford Ness used in the survey for Brown Hares in 2005 and 2006.

Reproduced by permission of Ordnance Survey. Š Crown Copyright and database right 2005. All rights reserved.

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Survey Areas

Description of areas

A. Lantern Marsh North & Sudbourne Beach

Estimated Area 54 hectares (0·54 km2) Central Grid Ref: TM458535 Habitat: Disturbed vegetated shingle, mudflats, saltmarsh Estimated Area 221 hectares (2·21 km2) Central Grid Ref: TM450515 Habitat: Vegetated shingle with gull colony, ungrazed marshy grassland Estimated Area 116 hectares (1·16 km2) Central Grid Ref: TM445500 Habitat: Vegetated shingle, grazed & ungrazed marshy grassland, saline lagoons Estimated Area 113 hectares (1·13 km2) Central Grid Ref: TM433490 Habitat: Grazing marsh, reedbed, buildings Estimated Area 234 hectares (2·34 km2) Central Grid Ref: TM440485 Habitat: Vegetated shingle, in variety of conditions, buildings Estimated Area 79 hectares (0·79 km2) Central Grid Ref: TM415470 Habitat: Vegetated shingle, in good condition Estimated Area 58 hectares (0·58 km2) Central Grid Ref: TM390455 Habitat: Vegetated shingle and gull colony

B. Lantern Marsh South & Cobra Mist

C. King’s Marshes

D. Airfield Marshes

E. Orford Ness, Lighthouse and Laboratory Area

F. Orford Beach G. Southern Spit to North Weir Point

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Orford Ness in 1964–66 by D. A. White (1968) but that survey had focussed on the southern ‘peninsular’ part of the site, called Orford Beach. Thus the aim of the present survey was to estimate the population size, density and habitat preferences of Brown Hare on the whole of Orford Ness.

Methods Brown Hares at Orford Ness were counted on 21 and 22 June 2005, and 23 June 2006, by direct observation during an early morning walk-over survey by the authors and a team of volunteer surveyors. The total area surveyed was 875 hectares (8·75km2). The whole site was divided into seven survey areas (Fig. 1) and teams of observers used binoculars to scan each one. At least two hours were spent in each survey area and observers moved to different locations within the area to be able to view as much of the habitat as possible.

The time and location of observations of hares were marked on a map. The openness of Orford Ness undoubtedly helped observers to spot Brown Hares although it is always possible that hares that were hidden in cover could be missed. There is also the possibility of double counting hares that moved between areas, but the noting of time, location and direction of movement helped to minimise this. However, some hares could have been counted by different teams and this is allowed for in the minimum-maximum counts in the results. In 2005, the grazing marshes and the shingle habitats were surveyed on different days. These areas are largely separated by a tidal creek, although it is possible that hares could move between these major habitats at the north end of the site, or by crossing the Bailey Bridge.

Results The results of the surveys at Orford Ness revealed that the density of Brown Hares was estimated to be 11·7 per km2 in June 2005 and had decreased by over 50% to 5·3 per km2 in June 2006 (Table 1). There was a marked variation in the density of hares in the various areas of the site, with the Orford Beach (F.) area supporting the greatest density in both years. In 2006, Orford Beach supported a density of Brown Hares at least 4 times higher than the next site (G) and about 10 times higher than the rest of the sites. The least favoured areas seemed to be the Airfield Marshes (D.), King’s Marshes (C.) and Lantern Marsh South (B.).

Discussion Hutchings and Smith (1996) and the Game Conservancy (2004) have recorded Brown Hare densities of 40 per km2 in optimal mixed farmland habitats in southern Britain. Thus the area of Orford Beach at Orford Ness appears to be provide very good habitat for Brown Hare (Table 1, site F). This area has the greatest extent of undisturbed vegetated shingle habitat and is largely free of the disturbances by people and previous human activities found at the centre of the site around the Lighthouse and Laboratories. The overall mean density of 11·7 per km2 in 2005, with over 100 individuals, shows that Orford Ness provides a good habitat for Brown Hares. Even after the decline evident in 2006, the hare density is comparable to the mean numbers for arable farmland in East Anglia (Hutchings & Smith, 2006). An interesting comparison is with the airside grasslands at Stansted Airport which supported about 28 adult Brown Hares in 2001 on an area of 246 ha, a density of 11·4 per km2 (PAA 2006).

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Table 1. Observations of Brown Hares at Orford Ness in each area of the site.

Site

June 2005 Number

June 2005 Density/km2

A B C D E F G Total

10 8 5 5 21* 36 17 102

18·5 3·6 4·3 4·4 9·0 45·6 29·3 11·7

June 2006 Number 2 6 2 2 6 24 4 46

June 2006 Density/km2 3·7 2·7 1·7 1·8 2·6 30·4 6·9 5·3

The number does not include possible double counted individuals. [* includes three leverets observed being born]

The detailed previous survey of Brown Hares on Orford Beach in 1964–66 also showed large changes in hare numbers between years. White (1968) reported direct counts of hares on Orford Beach (equivalent to sites F and G in the current survey) of 61 in Spring 1964, 95 in Autumn 1964, 165 in Autumn 1965, 146 in Spring 1966 and 182 in Autumn 1966. Thus the population had increased almost 300% during the survey period, probably as the Brown Hare numbers recovered from the severe winter of 1962-63 (White, 1968). The peak Brown Hare density recorded by White (1968) in Autumn 1966 was very high indeed at about 133 per km2 when compared to the present survey and the national survey of Hutchings and Smith (1996). The lowest density recorded in Spring 1964 of about 45 per km2 would be viewed as a high density population based on the 1990s survey. Thus Orford Beach in the 1960s must have provided prime habitat for Brown Hares.

The Game Conservancy (2004) recommend that the best way to survey for Brown Hares is at night using strong lights. This was not possible at Orford Ness for a number of reasons. However, the walk-over survey undertaken early and late in the day when hares are often active was an acceptable compromise. Due to the way the site was divided into survey areas, and the method adopted to avoid counting the same animals, we are reasonably confident that the numbers of Brown Hares counted can be considered as the minimum number alive in each area. We were much more likely to miss counting animals, and especially leverets, as they remained in cover out of view, than we were to double count a visible animal.

The main predator of the Brown Hare is the fox, but Hutchings and Smith (1996) found no evidence to show that fox predation played a significant role in determining hare numbers. Estates managed for shooting tend to have higher Brown Hare numbers due to the increased habitat richness associated with managing an estate for game shooting, rather than due to the fox control

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practised. Thus the decline in hare numbers seen at Orford Ness in 2006, compared to 2005, might be due to harsh winter weather, poor food supply or disease. The decline in hare numbers at Orford Ness is not of immediate concern, as Brown Hares can be prolific breeders and populations can recover quickly. Females may become pregnant as early as February and can produce three or even four litters of three or more leverets a year until September (Corbet & Harris, 1991). A further survey is planned for 2007 to monitor the population of this significant aspect of the conservation importance of Orford Ness National Nature Reserve.

Acknowledgements We gratefully thank the excellent National Trust Working Holiday teams at Orford Ness in June 2005 and 2006, who ably assisted the survey work. We also especially thank Jim Askins for his boatmanship.

References Corbet, G. B. & Harris, S. (Eds) (1991). The Handbook of British Mammals.

Blackwell Scientific Publications, Oxford.

Hutchings, M. R. & Harris, S. (1996). The current status of the brown hare (Lepus europaeus) in Britain. JNCC, Peterborough.

Penny Anderson Associates (2006). Generation 1. Environmental Statement Volume 10: Nature Conservation. BAA Stansted, Ove Arup & Partners Ltd, PAA Consultant Ecologists.

Suffolk Biodiversity Action Plan (2003). Species Action Plan: Brown Hare (Lepus europaeus). http://www.suffolk.gov.uk/Environment/Biodiversity/ SuffolkBiodiversityActionPlan/SpeciesActionPlans/ Tapper, S. & Parsons, N. (1984). The changing status of the Brown Hare in Britain. Mammal Review, 14: 57–70.

The Game Conservancy (2004). The Brown Hare. http://www.gct.org.uk/ text03.asp?PageId=55 UK Biodiversity Action Plan (2001). Species Action Plan: Brown Hare (Lepus europaeus). http://www.ukbap.org.uk/UKPlans.aspx?ID=410 White, D. A. (1968). Brown hares (Lepus europaeus) on Orford Beach, 19646. Trans. Suffolk Nat. Soc. 14: 49–57 Stuart Warrington and David Cormack The National Trust Quay Office Orford Quay Woodbridge Suffolk. IP12 2NU

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