BARN OWL HABITAT:
Working with the Barn Owl Conservation Trust (BOCT), significant steps have been taken to create habitat conducive and inviting for barn owls. At the outset barn owls weren't present at Underhill Wood - 2 years on they are resident. Spring / summer of 2016 they successfully raised a brood of 3 chicks, who all fledged. Almost every day I find pellets beneath their box - clear evidence that they are at least spending roosting time at Underhill Wood - my bet would be that they are hunting field voles in their field.
The key habitat enhancement I have made is cutting, on a 3 year rotation, what I call the barn owl field. This specific and deliberate management has given rise to an explosion in the field vole population - which is staple in the barn owl diet. No field voles, no barn owls., This rotation produces what is called rough grassland, which was prevalent in the UK countryside prior to the industrialisation of the agricultural sector. Grazing extensively by cattle used to produce this specific habitat. So, what is rough grassland. It is mixed height sward, where there is short grass and much longer, tufted grass. The short grass is eaten by field voles and the longer grass provides shelter. All swards must have a minimum height of 6 inches.
This is 5 star barn owl accommodation....
Barn owls suffer huge mortality rates and few owls survive more than 1 / 2 years. A period of high mortality is when owlets become mobile and begin to test their wings. Often they fall from their nest boxes and die. These boxes, conceived and designed by the BOCT, are close to 2 meters from floor to the entry / escape hole - so the owlet can only exit the box once it can properly fly. These nest boxes have reduced owlet mortality significantly.
This hunting stand enables the owl to hunt during cold winter nights, and do so without having to be on the wing.
Hunting on the wing consumes energy & calories - the hunting stand helps conserve both and therefore aids survival. I often find droppings (never pellets) under the stands. There are currently 3 stands at Underhill Wood.
Barn Owl Pellet Analysis:
As part of my work with the Wiltshire Mammal Group, I recently bagged and posted all the Barn Owl pellets, which have been retrieved from beneath the Barn Owl box over the past year or so. This analysis was done by Paul Wexler at Lackham College, Lacock, Wilts.
This is a key extract from Paul's email to me following the analysis - 'I have pooled the data for overall totals here. Wood mice appeared at a relatively high proportion compared to other site samples we have done, but as expected Field voles are the common prey. Interestingly no Pygmy shrew'.
As Paul notes Field Vole are the main food source for Barn Owls but they will predate more widely - the ancient hedgerows which border the Barn Owl field are abundant in Wood Mice so while the data is atypical, it fits the UWNR environment. This conclusion was supported by UWNR friend and ecologist Gareth Harris - he noted: 'Field vole are characteristic of grassland areas (which may range from grassy woodland glades to cereal fields to rough grassland) whilst wood mice are characteristic of wooded areas, hedgerows etc. There is of course overlap in their habitat use. You of course have both habitats in abundance, so the owls are able to hunt in areas with a diverse food source and where food is seasonally abundant'.
The pellets bagged, dated and ready for dispatch....
This analysis gives a window into what prey species the Barn Owls are hunting and eating i.e. their diet....
These are the results:
Latin Name Common Name No of individuals
Microtus agrestis Field Vole 31
Apodemus sylvaticus Wood Mouse 15
Myodes glareolus Bank Vole 1
Sorex araneus Common Shrew 4
Barn Owl field rotational cut:
Mid-July 2017 and I have just completed the annual rotational cut of 1/3 of the Barn Owl field. This year I have taken the additional step to remove all the grass cuttings, so the grass thatch which remains after cutting, is able to repair and restore. Grass growth in the section I cut was rampant and my concern was that the decaying cuttings would rot the all important thatch. The removed cuttings have been specifically placed to aid the snake species found on the reserve.
Grass cuttings being removed as part of the annual rotational cut - mid July 2017.
Barn Owl Offspring - Summer 2017...
For the second year in a row the UWNR resident Barn Owls have had a brood of owlets. Mid-July 2017 and they are very vocal at night demanding food from the parent birds.
This is great news - they have returned in the summer of 2017 to breed, after successfully breeding in the summer of 2016.
Eco-mimicry.....
One of the medium term plans we have for UWNR is to create a small open agricultural barn, to store hay, straw and implements. This would provide habitat for voles, which are the key prey species for Barn Owls, and nesting sites for Hirundinidae (Swifts, Swallows and House Martins).
In the meantime, I have constructed this outdoor haystack, which is located in the Barn Owl field and will provide valuable wintering habitat for field voles, bank voles & wood mice. Time will tell if this gives rise to a greater prey population come spring / summer 2018...
Bird Survey
On Sunday, April 29th working with friends of UWNR, Laura, Elinor and Richard (without his expertise we would have truly struggled), we carried out the first proper bird survey. We arrived at the reserve before dawn (fortified by copious amounts of pre-dawn coffee) and then waited, wandered slowly, listened, observed and recorded. The very early dawn chorus was a wall of noise - the singing dominated by wrens, blackbirds, song thrushes and robins. At around 05.45 other species got into the act...
The following is a list of all birds heard and seen. Without doubt the highlight of the morning was identifying a Willow Tit!
Willow Tit
Song Thrush
Robin
Wood Pigeon
Moorhen
Blackbird
Wren
Great Tit
Marsh Tit
Blue Tit
Long Tailed Tit
Chiff Chaff
Greater Spotted Woodpecker
Rooks
Willow Warbler
Blackcap
Goldcrest
Mistle Thrush
Bull Finch
Pied Wagtail
Nuthatch
Chaffinch
Dunnock
Buzzard
Canada Geese
Swan
Little Grebe
Mallard
Mandarin Duck\
Raven
Pheasant
At the beginning of 2021 I collated all the survey data from 2016 - 2019. So an up-dated species list (for the moment!).
Barn owl, tyto alba; Blackbird, turdus merula; Blackcap, sylvia atricapilla; Blue tit, cyanistes caeruleus; Bull finch, pyrrhula pyrrhula; Buzzard, buteo buteo; Canada goose, branta canadensis; Chaffinch, fringilla coelebs; Chiff chaff, phylloscopus collybita; Crow, corvus corone; Dunnock, prunella modularis; Fieldfare, turdus pilaris; Goldcrest, regulus regulus; Greater spotted woodpecker, dendrocopos major; Great tit, parus major; Goldfinch, carduelis carduelis; Goshawk, accipiter gentilis; Heron, ardea cinerea; Hobby, falco subbuteo; Jackdaw, corvus monedula; Jay, garrulus glandarius; Kestrel, falco tinnunculus; Kingfisher, alcedo atthis; Kite, milvus milvus; Little grebe, tachybaptus ruficolis; Long tailed tit, aegithalos caudatus; Magpie, pica pica; Mallard, anas platyrhynchos; Mandarin duck, aix galericulata; Tufted duck, aythya fuligula; Marsh tit, poecile palustris; Mistle thrush, turdus viscivorus; Moorhen, gallinula chloropus; Nuthatch, sitta europaea; Pheasant, phasianus olchicus; Pied wagtail, motacilla alba; Raven, corvus corax; Red legged partridge, alectoris rufa; Redwing, turdus iliacus; Robin, erithacus rubecula; Rook, corvus frugilegus; Snipe, gallinago gallinago; Song thrush, turdus philomelos; Sparrowhawk, accipiter nisus; Swan, cygnus cygnus; Tawny owl, strix aluco; Tree creeper, certhia familiaris; Wood pigeon, columba palumbus; Willow tit, poecile montanus; Willow warbler, Phylloscopus trochilus; Wren, troglodytes troglodytes.