Operation Riverside Link IMPROVING RIPARIAN HABITAT TO INCREASE BARN OWL NUMBERS and MONITOR THEIR P

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Operation Riverside LinkIMPROVING RIPARIAN
HABITAT TO INCREASE BARN OWL NUMBERS andMONITOR
THEIR POPULATION IN ENGLAND AND WALES
The Barn Owl An Indicator Species for Riparian
Habitat

• WILDLIFE CONSERVATION PARTNERSHIP
• Colin Shawyer
• MUniv CBiol FIBiol MIEEM

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What is the value of including a terrestrial bird
in the suite of Environment Agency Indicators ?

• Why is the Barn Owl relevant as an indicator of
  riparian quality ?

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1932 to1982
1932 12,000 breeding pairs
1982 3,800 breeding pairs (70 decline)
Contraction of population into river valleys
fenlands
From Shawyer 1987
Survey found river corridors provided 80 of UK
population Riparian networks established as prime
habitat in UK
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1990 - Operation Riverside Link
beginsRestoring river-bank habitats -
countrywide
The EA target to improve 500 km of river-bank
by 2011

• In 1990 connectivity of habitat on a countrywide
  scale was a new and untried concept in the UK
• Operation Riverside Link sought to change this
• Today, 15 years later - an almost unbroken 800
  km corridor has been created from Northumberland
  to Sussex
• This corridor and its branches currently support
  700 breeding pairs (about one-fifth of the
  English population)

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Increased diversity and abundance of small
mammals and invertebrates are being achieved in
these restored grassland habitats
Increased biodiversity is being reflected in the
recovery of Barn Owl (and Kestrel) populations
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Nestboxes are installed on these new prey-rich
habitats

• For direct conservation benefit

• To audit the progress and success of river-bank
  restoration
• Occupancy, breeding success and populaton size
  is monitored annually

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By 2006700 breeding pairs on 900 km of restored
river bank
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Riparian networks provide prime foraging habitat,
prey-rich corridors for the natal dispersal of
young and connectivity of grassland habitat,
countrywide.

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(No Transcript)
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Nestboxes like these
They offer

• Durability
• Thermal conductivity
• Ease of installation
• Use of non-metallic fixings
• Ease of monitoring
• Biodegradability

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Field Voles need rough-grassland
To feed, breed and to enable young to disperse
successfully

• structure of grass is critical (rank, tussocky,
  dead-grass litter layer)
• size of Barn Owls breeding range 350 ha and 700
  ha
• 35 ha (or 5-10 km corridors) of rough-grassland
  normally needed within this home range
• Field Vole abundance can vary from 5 to 3000
  voles per ha in whole grasslands
• this density is dependent on the structural
  quality of the grassland and the phase of the
  3-year vole cycle

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and they work well
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2006 -The latest habitat link in the chain
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Presentation to EA Conservation
and Ecology Symposium
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The monitoring yearFebruary/March pair
prospect river-bank nestsite

• April large clutches are sometimes laid

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May - hatching and female moult starts
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June - food mountains can appear
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growing up
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large enough to sex, age and ring
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July - over halfway to fledging