270 THE WILTSHIRE ARCHAEOLOGICAL AND NATURAL HISTORY MAGAZINE 
outside the reserve. The Belties help these birds by 
keeping the streams clear of vegetation. 
Throughout the year, the reserve is a favourite 
fishing site for Grey Heron Ardea cinerea, which 
probably also take frogs in the meadows. 
Just a few years ago Cuckoos Cuculus canorus 
came in large numbers, but now there are only one 
or two each year. 
Barn Owls Tyto alba hunt over Big Forty and the 
fen, but are not Known to have bred while Tawny 
Owls Strix aluco do, with two pairs in some years. 
Reed Buntings Emberiza schoeniclus have bred 
successfully in most years, at least one pair every 
year since 2000. This year there were two females 
and one male (the bird is sometimes polygamous). 
At Jones’s Mill recently they have nested in the 
isolated shrubs in and around the fens where they 
hunt their food, but their usual position is at 
ground level or on sedge tussocks (Snow & Perrins 
1998, 1675). During the summer they are 
exclusively insectivorous. They have been recorded 
on the reserve only during the breeding season. The 
bird’s usual behaviour after breeding is to 
congregate in flocks and feed largely on small seeds 
of arable weeds. Their decline, like that of many 
farmland birds, is thought to be caused by poorer 
survival rates of fledglings during the winter now 
that weeds are scarce (Wingfield Gibbons et al., 
1993, 436). 
The carr and northern woodland have breeding 
Sparrowhawk A. nisus, Green Woodpecker Picus 
viridis, Great Spotted Woodpecker Dendrocopos 
major, Nuthatch Sitta europaea and Treecreeper 
Certhia familiaris. In recent years there have been 
three pairs each of Song Thrush Turdus philomelos, 
Goldcrest Regulus regulus and Long-tailed Tits 
Aegithales canolatus. In the winter, flocks of up to 
twenty or so Long-tailed Tits roam through the 
woods, sometimes accompanied by Blue, Marsh 
and Coal Tits Parus caeruleus, P palustris and P. ater 
and by Goldcrests R. regulus. 
There are very few Dunnocks Prunella modularis 
on the reserve (just two pairs in 2003). They are found 
where there are brambles — often a preferred feeding 
ground included in their territory (Bishton, 2001). 
Mammals 
There have been a few small-scale investigations, 
but our knowledge of the mammals depends mostly 
on casual observations. 
The only British Insectivore that has never 
been recorded is the Hedgehog Erinaceus europaeus. 
Great Spotted Woodpecker 
All three shrews have been found, the Water Shrew 
Neomys fodiens, just once in the very early days of 
the reserve. Moles Jalpa europea are widespread. 
There are at least two bats, probably many 
more. 
Rabbits Oryctolagus cuniculus are common, but 
no hares Lepus capensis have ever been seen. 
The Grey Squirrel Scirus carolinensis is 
common. Surprisingly, the Bank Vole Clethrionomys 
glareolus has been seen only once and the Field Vole 
Microtus agrestis was not recorded until very 
recently, although both are almost certainly present 
in good numbers. In the 1940s there were ‘masses’ 
of Water Vole Arvicola terrestris (Wall, 1999) and they 
were still common in the 1980s but then the 
numbers slumped. Mink Mustela vison, that I saw 
with young in the river, were the probable cause. 
The vole numbers recovered to some extent but 
there are still very few. Recently found remains of 
predated Crayfish probably mean that Mink have 
returned. The records include Woodmouse 
Apodemus sylvaticus and Yellow-necked Mouse A. 
flavicollis and also Harvest Mice Micromys minutus. 
Dormice Muscardinus avellanarius have been found 
