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Bird Conservation
Global evidence for the effects of interventions
Synopses of Conservation Evidence, Volume 2
ISBN 978-1-907807-19-0 (Pbk)
ISBN 978-1-907807-20-6 (Hbk)
ISBN 978-1-907807-21-3 (eBook)
Copyright © 2013 William J. Sutherland
This book should be quoted as Williams, D. R., Pople, R. G., Showler, D. A., Dicks, L. V., Child, M. F., zu Ermgassen, E. K. H. J. and Sutherland, W. J. (2013) Bird Conservation: Global evidence for the effects of interventions. Exeter, Pelagic Publishing.
All rights reserved. Apart from short excerpts for use in research or for reviews, no part of this document may be printed or reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, now known or hereafter invented or otherwise without prior permission from the publisher.
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library.
Contents
Advisory board
About the authors
Acknowledgements
1. About this book
2. Habitat protection
Key messages
2.1. Legally protect habitats
2.2. Ensure connectivity between habitat patches
2.3. Provide or retain un-harvested buffer strips
3. Education and awareness raising
Key messages
3.1. Raise awareness amongst the general public through campaigns and public information
3.2. Provide bird feeding materials to families with young children
3.3. Enhance bird taxonomy skills through higher education and training
3.4. Provide training to conservationists and land managers on bird ecology and conservation
4. Threat: Residential and commercial development
Key messages
4.1. Angle windows to reduce collisions
4.2. Mark or tint windows to reduce collision mortality
5. Threat: Agriculture
Key messages – All farming systems
Key messages – Arable farming
Key messages – Livestock farming
Key messages – Perennial, non-timber crops
Key messages – Aquaculture
All farming systems
5.1. Support or maintain low-intensity agricultural systems
5.2. Practise integrated farm management
5.3. Food labelling schemes relating to biodiversity-friendly farming
5.4. Increase the proportion of natural/semi-natural vegetation in the farmed landscape
5.5. Pay farmers to cover the costs of conservation measures
5.6. Cross compliance standards for all subsidy payments
5.7. Reduce field size (or maintain small fields)
5.8. Provide or retain set-aside areas in farmland
5.9. Manage hedges to benefit wildlife
5.10. Plant new hedges
5.11. Manage stone-faced hedge banks to benefit birds
5.12. Manage ditches to benefit wildlife
5.13. Protect in-field trees
5.14. Plant in-field trees
5.15. Tree pollarding and tree surgery
5.16. Plant wild bird seed or cover mixture
5.17. Plant nectar flower mixture/wildflower strips
5.18. Create uncultivated margins around intensive arable or pasture fields
5.19. Plant grass buffer strips/margins around arable or pasture fields
5.20. Use mowing techniques to reduce chick mortality
5.21. Provide refuges in fields during harvest or mowing
5.22. Mark bird nests during harvest or mowing
5.23. Relocate nests at harvest time to reduce nestling mortality
5.24. Make direct payments per clutch for farmland birds
5.25. Control scrub on farmland
5.26. Take field corners out of management
5.27. Reduce conflict by deterring birds from taking crops
Arable farming
5.28. Increase crop diversity
5.29. Implement ‘mosaic management’
5.30. Leave overwinter stubbles
5.31. Plant nettle strips
5.32. Leave unharvested cereal headlands within arable fields
5.33. Plant crops in spring rather than autumn
5.34. Undersow spring cereals, with clover for example
5.35. Plant more than one crop per field (intercropping)
5.36. Revert arable land to permanent grassland
5.37. Reduce tillage
5.38. Add 1% barley into wheat crop for corn buntings
5.39. Leave uncropped, cultivated margins or plots (includes lapwing and stone curlew plots)
5.40. Create skylark plots
5.41. Create corn bunting plots
5.42. Plant cereals in wide-spaced rows
5.43. Create beetle banks
Livestock farming
5.44. Maintain species-rich, semi-natural grassland
5.45. Reduce management intensity on permanent grasslands
5.46. Reduce grazing intensity
5.47. Provide short grass for waders
5.48. Raise mowing height on grasslands
5.49. Delay mowing date or first grazing date on grasslands
5.50. Leave uncut rye grass in silage fields
5.51. Plant cereals for wholecrop silage
5.52. Maintain lowland heathland
5.53. Maintain rush pastures
5.54. Maintain traditional water meadows
5.55. Maintain upland heath/moor
5.56. Plant Brassica fodder crops
5.57. Use mixed stocking
5.58. Use traditional breeds of livestock
5.59. Maintain wood pasture and parkland
5.60. Exclude grazers from semi-natural habitats (including woodland)
5.61. Protect nests from livestock to reduce trampling
5.62. Mark fences to reduce bird collision mortality
5.63. Create open patches or strips in permanent grassland
Perennial, non-timber crops
5.64. Maintain traditional orchards
5.65. Manage perennial bioenergy crops to benefit wildlife
Aquaculture
5.66. Reduce conflict with humans to reduce persecution
5.67. Scare birds from fish farms
5.68. Disturb birds at roosts
5.69. Use electric fencing to exclude fish-eating birds
5.70. Use netting to exclude fish-eating birds
5.71. Disturb birds using foot patrols
5.72. Use ‘mussel socks’ to prevent birds from attacking shellfish
5.73. Translocate birds away from fish farms
5.74. Increase water turbidity to reduce fish predation by birds
5.75. Provide refuges for fish within ponds
5.76. Use in-water devices to reduce fish loss from ponds
5.77. Spray water to deter birds from ponds
5.78. Deter birds from landing on shellfish culture gear
6. Threat: Energy production and mining
Key messages
6.1. Paint wind turbines to increase their visibility
7. Threat: Transportation and service corridors
Key messages – Verges and airports
Key messages – Power lines and electricity pylons
Verges and airports
7.1. Mow roadside verges
7.2. Sow roadside verges
7.3. Scare or otherwise deter birds from airports
Power lines and electricity pylons
7.4. Bury or isolate power lines to reduce incidental mortality
7.5. Remove earth wires to reduce incidental mortality
7.6. Thicken earth wire to reduce incidental mortality
7.7. Mark power lines to reduce incidental mortality
7.8. Use raptor models to deter birds and so reduce incidental mortality
7.9. Add perches to electricity pylons to reduce electrocution
7.10. Insulate power pylons to prevent electrocution
7.11. Use perch-deterrents to stop raptors perching on pylons
7.12. Reduce electrocutions by using plastic, not aluminium, leg rings to mark birds
8. Threat: Biological resource use
Key messages – reducing exploitation and conflict
Key messages – reducing fisheries bycatch
Reducing exploitation and conflict
8.1. Use legislative regulation to protect wild populations
8.2. Increase ‘on-the-ground’ protection to reduce unsustainable levels of exploitation
8.3. Promote sustainable alternative livelihoods
8.4. Use education programmes and local engagement to help reduce persecution or exploitation of species
8.5. Employ local people as ‘biomonitors’
8.6. Mark eggs to reduce their appeal to egg collectors
8.7. Relocate nestlings to reduce poaching
8.8. Use wildlife refuges to reduce hunting disturbance
8.9. Introduce voluntary ‘maximum shoot distances’
8.10. Provide ‘sacrificial’ grasslands to reduce the impact of wild geese on crops
8.11. Move fish-eating birds to reduce conflict with fishermen
8.12. Scare fish-eating birds from areas to reduce conflict
Reduce fisheries bycatch
8.13. Set longlines at night to reduce seabird bycatch
8.14. Turn deck lights off during night-time setting of longlines to reduce bycatch
8.15. Use streamer lines to reduce seabird bycatch on longlines
8.16. Use larger hooks to reduce seabird bycatch
8.17. Use a water cannon when setting longlines to reduce seabird bycatch
8.18. Set lines underwater to reduce seabird bycatch
8.19. Set longlines at the side of the boat to reduce seabird bycatch
8.20. Use a line shooter to reduce seabird bycatch
8.21. Use bait throwers to reduce seabird bycatch
8.22. Tow buoys behind longlining boats to reduce seabird bycatch
8.23. Dye baits to reduce seabird bycatch
8.24. Use high-visibility longlines to reduce seabird bycatch
8.25. Use a sonic scarer when setting longlines to reduce seabird bycatch
8.26. Weight baits or lines to reduce longline bycatch of seabirds
8.27. Use shark liver oil to deter birds when setting lines
8.28. Thaw bait before setting lines to reduce seabird bycatch
8.29. Reduce seabird bycatch by releasing offal overboard when setting longlines
8.30. Use bird exclusion devices such as ‘Brickle curtains’ to reduce seabird mortality when hauling longlines
8.31. Use acoustic alerts on gillnets to reduce seabird bycatch
8.32. Use high-visibility mesh on gillnets to reduce seabird bycatch
8.33. Reduce gillnet deployment time to reduce seabird bycatch
8.34. Mark trawler warp cables to reduce seabird collisions
8.35. Reduce ‘ghost fishing’ by lost/discarded gear
8.36. Reduce bycatch through seasonal or area closures
9. Threat: Human intrusions and disturbance
Key messages
9.1. Use wildlife refuges to reduce hunting disturbance
9.2. Use signs and access restrictions to reduce disturbance at nest sites
9.3. Set minimum distances for approaching birds (buffer zones)
9.4. Provide paths to limit the extent of disturbance
9.5. Reduce visitor group sizes
9.6. Use voluntary agreements with local people to reduce disturbance
9.7. Start educational programmes for personal watercraft owners
9.8. Habituate birds to human visitors
9.9. Use nest covers to reduce the impact of research on predation of ground-nesting seabirds
10. Threat: Natural system modifications
Key messages
10.1. Use prescribed burning
10.2. Use fire suppression/control
10.3. Protect nest trees before burning
10.4. Clear or open patches in forests
10.5. Clearcut and re-seed forests
10.6. Thin trees within forests
10.7. Coppice trees
10.8. Use patch retention harvesting instead of clearcutting
10.9. Use selective harvesting/logging instead of clearcutting
10.10. Use variable retention management during forestry operations
10.11. Use shelterwood cutting instead of clearcutting
10.12. Manage woodland edges for birds
10.13. Manually control or remove mid-storey and ground-level vegetation (including mowing, chaining, cutting etc)
10.14. Replace non-native species of tree/shrub
10.15. Provide deadwood/snags in forests
10.16. Remove coarse woody debris from forests
10.17. Apply herbicide to mid- and under-storey vegetation
10.18. Treat wetlands with herbicide
10.19. Employ grazing in natural and semi-natural habitats
10.20. Plant trees to act as windbreaks
10.21. Re-seed grasslands
10.22. Fertilise artificial grasslands
10.23. Raise water levels in ditches or grassland
10.24. Manage water level in wetlands
10.25. Use environmentally sensitive flood management
10.26. Use greentree reservoir management
10.27. Plough habitats
10.28. Create scrapes and pools in wetlands and wet grasslands
11. Habitat restoration and creation
Key messages
11.1. Restore or create forests
11.2. Restore or create grasslands
11.3. Restore or create traditional water meadows
11.4. Restore or create shrubland
11.5. Restore or create savannas
11.6. Restore or create wetlands and marine habitats
12. Threat: Invasive alien and other problematic species
Key messages – reduce predation by other species
Key messages – reduce incidental mortality during predator eradication or control
Key messages – reduce nest predation by excluding predators from nests or nesting areas
Key messages – reduce mortality by reducing hunting ability or changing predator behaviour
Key messages – reduce competition with other species for food and nest sites
Key messages – reduce adverse habitat alteration by other species
Key messages – reduce parasitism and disease
Key messages – reduce detrimental impacts of other problematic species
Reduce predation by other species
12.1. Remove or control predators to enhance bird populations and communities
Predator control on islands
12.2. Control avian predators on islands
12.3. Control mammalian predators on islands
12.4. Control invasive ants on islands
12.5. Control predators not on islands
12.6. Reduce predation by translocating predators
Reduce incidental mortality during predator eradication or control
12.7. Do birds take bait designed for pest control?
12.8. Distribute poison bait using dispensers
12.9. Use repellents on baits
12.10. Use coloured baits to reduce accidental mortality during predator control
Reduce nest predation by excluding predators from nests or nesting areas
12.11. Physically protect nests from predators using non-electric fencing
12.12. Protect bird nests using electric fencing
12.13. Physically protect nests with individual exclosures/barriers or provide shelters for chicks
12.14. Can nest protection increase nest abandonment?
12.15. Can nest protection increase predation of adults and chicks?
12.16. Use artificial nests that discourage predation
12.17. Use multiple barriers to protect nests
12.18. Plant nesting cover to reduce nest predation
12.19. Use snakeskin to deter mammalian nest predators
12.20. Use mirrors to deter nest predators
12.21. Use naphthalene to deter mammalian predators
12.22. Use ultrasonic devices to deter cats
12.23. Protect nests from ants
12.24. Guard nests to prevent predation
12.25. Use ‘cat curfews’ to reduce predation
12.26. Use lion dung to deter domestic cats
12.27. Play spoken-word radio programmes to deter predators
Reduce mortality by reducing hunting ability or changing predator behaviour
12.28. Use collar-mounted devices to reduce predation
12.29. Use supplementary feeding to reduce predation
12.30. Use aversive conditioning to reduce nest predation
12.31. Reduce predation by translocating nest boxes
Reduce competition with other species for food and nest sites
12.32. Reduce inter-specific competition for nest sites by removing competitor species
12.33. Reduce inter-specific competition for nest sites by modifying habitats to exclude competitor species
12.34. Protect nest sties from competitors
12.35. Reduce competition between species by providing nest boxes
12.36. Reduce inter-specific competition for food by removing or controlling competitor species
Reduce adverse habitat alteration by other species
12.37. Reduce adverse habitat alterations by excluding problematic species
12.38. Control or remove habitat-altering mammals
12.39. Remove problematic vegetation
12.40. Use buffer zones to reduce the impact of invasive plant control
Reduce parasitism and disease
12.41. Remove/treat endoparasites and diseases
12.42. Exclude or control ‘reservoir species’ to reduce parasite burdens
12.43. Remove/treat ectoparasites to increase survival or reproductive success
12.44. Guard nests to reduce risk of ectoparasites
12.45. Remove/control brood parasites
12.46. Use false brood parasite eggs to discourage brood parasitism
12.47. Provide supplementary food to increase parental presence and so reduce brood parasitism
12.48. Alter artificial nest sites to discourage brood parasitism
Reduce detrimental impacts of other problematic species
12.49. Use copper strips to exclude snails from nests
13. Threat: Pollution
Key messages – Industrial pollution
Key messages – Agricultural pollution
Key message – Air-borne pollutants
Key messages – Excess energy
Industrial pollution
13.1. Clean birds following oil spills
13.2. Relocate birds following oil spills
13.3. Deter or prevent birds from landing on toxic pools
13.4. Use repellents to deter birds from landing on pools polluted by mining
Agricultural pollution
13.5. Reduce pesticide or herbicide use generally
13.6. Restrict certain pesticides or other agricultural chemicals
13.7. Provide food for vultures to reduce mortality from diclofenac
13.8. Make selective use of spring herbicides
13.9. Use organic rather than mineral fertilisers
13.10. Reduce chemical inputs in permanent grassland management
13.11. Leave headlands in fields unsprayed (conservation headlands)
13.12. Provide unfertilised cereal headlands in arable fields
13.13. Plant riparian buffer strips
13.14. Provide buffer strips around in-field ponds
Air-borne pollutants
13.15. Use lime to reduce acidification in lakes
Excess energy
13.16. Reduce incidental mortality from birds being attracted to artificial lights
13.17. Turn off lights to reduce mortality from artificial lights
13.18. Reduce the intensity of lighthouse beams
13.19. Shield lights to reduce mortality from artificial lights
13.20. Use flashing lights to reduce mortality from artificial lights
13.21. Use lights low in spectral red to reduce mortality from artificial lights
13.22. Use volunteers to collect downed birds and rehabilitate them
14. Threat: Climate change, extreme weather and geological events
Key messages
14.1. Water nesting mounds to increase incubation success in malleefowl
14.2. Replace nesting substrate following severe weather
15. General responses to small/declining populations
Key messages – inducing breeding, rehabituation and egg removal
Key messages – provide artificial nesting sites
Key messages – foster chicks in the wild
Key messages – provide supplementary food
Key messages – translocations
15.1. Use artificial visual and auditory stimuli to induce breeding in wild populations
15.2. Rehabilitate injured birds
15.3. Remove eggs from wild nests to increase reproductive output
15.4. Provide artificial nesting sites
15.5. Clean nest boxes to increase occupancy or reproductive success
15.6. Use differently-coloured artificial nests
15.7. Provide nesting material for wild birds
15.8. Repair/support nests to support breeding
15.9. Artificially incubate eggs or warm nests
15.10. Provide nesting habitat for birds that is safe from extreme weather
15.11. Remove vegetation to create nesting areas
15.12. Guard nests to increase nest success
Foster chicks in the wild
15.13. Foster eggs or chicks with wild conspecifics
15.14. Foster eggs or chicks with wild non-conspecifics (cross-fostering)
Provide supplementary food
15.15. Provide supplementary food to increase reproductive success
15.16. Provide supplementary food to allow the rescue of a second chick
15.17. Provide supplementary food to increase adult survival
15.18. Can supplementary feeding increase predation or parasitism?
15.19. Provide supplementary food through the establishment of food populations
15.20. Use perches to increase foraging success
15.21. Place feeders close to windows to reduce collisions
15.22. Provide supplementary water to increase survival or reproductive success
15.23. Provide calcium supplements to increase survival or reproductive success
Translocations
15.24. Translocate birds to re-establish populations or increase genetic variation
15.25. Use techniques to increase the survival of species after capture
15.26. Ensure translocated birds are familiar with each other before release
15.27. Ensure genetic variation to increase translocation success
15.28. Translocate nests to avoid disturbance
15.29. Use vocalisations to attract birds to new sites
15.30. Use decoys to attract birds to new sites
15.31. Alter habitat to encourage birds to leave an area
16. Captive breeding, rearing and releases (ex situ conservation)
Key messages – captive breeding
Key messages – release of captive-bred individuals
Captive breeding
16.1. Use captive breeding to increase or maintain populations
16.2. Can captive breeding have deleterious effects on individual fitness?
16.3. Use artificial insemination in captive breeding
16.4. Freeze semen for use in artificial insemination
16.5. Wash contaminated semen and use it for artificial insemination
16.6. Artificially incubate and hand-rear birds in captivity
16.7. Use puppets to increase the success of hand-rearing
Release of captive-bred individuals
16.8. Release captive-bred individuals into the wild to restore or augment wild populations
16.9. Use appropriate populations to source released populations
16.10. Use holding pens at release sites
16.11. Clip birds’ wings on release
16.12. Release birds in groups
16.13. Release chicks and adults in ‘coveys’
16.14. Release birds as adults or sub-adults, not juveniles
16.15. Use ‘anti-predator training’ to improve survival after release
16.16. Use ‘flying training’ before release
16.17. Provide supplementary food during and after release
16.18. Use microlites to help birds migrate
Index
Advisory board
We thank the following people for advising on the scope and content of this synopsis:
Dr Andrew Brown, Natural England
Dr David Gibbons, Royal Society for the Protection of Birds
Dr Roger Mitchell, Natura International
Dr Jörn Scharlemann, UNEP-World Conservation Monitoring Centre
Dr Gavin Siriwardena, British Trust for Ornithology
Dr Alison Stattersfield, BirdLife International
Dr David Stroud, Joint Nature Conservation Committee
Professor Des Thompson, Scottish Natural Heritage
Acknowledgements
This synopsis was funded by the Natural Environment Research Council and Arcadia.
We would also like to thank Dr Stephanie Prior for providing support throughout the project and all the people who gave help and advice and allowed us access to their research: Helen Baker (Joint Nature Conservation Committee), Leon Bennun (BirdLife International), Mark Bolton (Royal Society for the Protection of Birds, RSPB), Chris Bowden (RSPB), Jöel Bried (University of the Azores), Rhys Bullman (Scottish Nature Conservancy), Bob Carling (Pelagic Publishing), Motti Charter (Tel Aviv University), Mariano Codesido (University of Buenos Aires), James Dwyer (Virginia Tech), Rob Field (RSPB), Graham Fulton (Edith Cowan University), Emma Gyuris (James Cook University), Wendy Johnson (Hawaii Audubon Society), Tim Johnson (UNEP – World Conservation Monitoring Centre), Naoki Katayama (University of Tokyo), Andrew Kelly (Royal Society for the Prevention of Cruelty to Animals), Will Kirby (RSPB), Raivo Mänd (University of Tartu), Nigel Massen (Pelagic Publishing), Marcos Moleón Páiz (University of Granada), Roberto Muriel (Consejo Superior de Investigaciones Cientificas), Itziar Olmedo (University of Cambridge), Ray Poulin (Royal Saskatchewan Museum), David Priddel (Department of Environment, Climate Change and Water, New South Wales), Casey Primacio (Hawaii Audubon Society), C. John Ralph (US Department of Agriculture Forest Service), Michel Robert (Canadian Wildlife Service), Maurizio Sarà (University of Palermo), Debbie Saunders (Australian National University), Phil Seddon (University of Otago), Danaë Sheehan (RSPB), Jennifer Smart (RSPB), Ian Smales (Biosis Research), John Smallwood (Montclair State University), Juliet Vickery (British Trust for Ornithology) and Matt Wagner (Texas Parks and Wildlife Department).
1. About this book
The purpose of Conservation Evidence synopses
Conservation Evidence synopses do |
Conservation Evidence synopses do not |
• Bring together scientific evidence captured by the Conservation Evidence project (over 3,000 studies so far) on the effects of interventions to conserve biodiversity |
• Include evidence on the basic ecology of species or habitats, or threats to them |
• List all realistic interventions for the species group or habitat in question, regardless of how much evidence for their effects is available |
• Make any attempt to weight or prioritise interventions according to their importance or the size of their effects |
• Describe each piece of evidence, including methods, as clearly as possible, allowing readers to assess the quality of evidence |
• Weight or numerically evaluate the evidence according to its quality |
• Work in partnership with conservation practitioners, policymakers and scientists to develop the list of interventions and ensure we have covered the most important literature |
• Provide answers to conservation problems. We provide scientific information to help with decision-making |
Who is this synopsis for?
If you are reading this, we hope you are someone who has to make decisions about how best to support or conserve biodiversity. You might be a land manager, a conservationist in the public or private sector, a farmer, a campaigner, an advisor or consultant, a policymaker, a researcher or someone taking action to protect your own local wildlife. Our synopses summarise scientific evidence relevant to your conservation objectives and the actions you could take to achieve them.
We do not aim to make your decisions for you, but to support your decision-making by telling you what evidence there is (or isn’t) about the effects that your planned actions could have.
When decisions have to be made with particularly important consequences, we recommend carrying out a systematic review, as the latter is likely to be more comprehensive than the summary of evidence presented here. Guidance on how to carry out systematic reviews can be found from the Centre for Evidence-Based Conservation at the University of Bangor (www.cebc.bangor.ac.uk).
The Conservation Evidence project
The Conservation Evidence project has three parts:
An online, open access journal Conservation Evidence publishes new pieces of research on the effects of conservation management interventions. All our papers are written by, or in conjunction with, those who carried out the conservation work and include some monitoring of its effects.
An ever-expanding database of summaries of previously published scientific papers, reports, reviews or systematic reviews that document the effects of interventions.
Synopses of the evidence captured in parts one and two on particular species groups or habitats. Synopses bring together the evidence for each possible intervention. They are freely available online and available to purchase in printed book form.
These resources currently comprise over 3,000 pieces of evidence, all available in a searchable database on the website www.conservationevidence.com.
Alongside this project, the Centre for Evidence-Based Conservation (www.cebc.bangor.ac.uk) and the Collaboration for Environmental Evidence (www.environmentalevidence.org) carry out and compile systematic reviews of evidence on the effectiveness of particular conservation interventions. These systematic reviews are included on the Conservation Evidence database.
Of the 322 bird conservation interventions identified in this synopsis, five are the subjects of current systematic reviews:
• How does the impact of grazing on heathland compare with the impact of burning, cutting or no management? http://www.environmentalevidence.org/SR14.html
• Is predator control an effective strategy for enhancing bird populations? http://www.environmentalevidence.org/SR38.html.
• Do matrix features affect species movement? http://www.environmentalevidence.org/SR43.html
• Does structural connectivity facilitate dispersal of native species in Australia’s fragmented terrestrial landscape? http://www.environmentalevidence.org/SR44.html
• How do thinning and burning treatments in south-western conifer forests in the United States affect wildlife distribution, abundance and population performance? http://www.environmentalevidence.org/SR66.html
In addition, three systematic reviews provide important information on the impacts of threats on bird populations:
• Effects of wind turbines on bird abundance. http://www.environmentalevidence.org/SR4.html
• What is the impact of public access on the breeding success of ground-nesting and cliff-nesting birds? http://www.environmentalevidence.org/SR16.html
• What are the impacts of human recreational activity on the distribution, nest-occupancy rates and reproductive success of breeding raptors? http://www.environmentalevidence.org/SR27.html
Another provides evidence for how to apply an intervention:
• Do trapping interventions effectively reduce or eradicate populations of the American mink (Mustela vison)? http://www.environmentalevidence.org/SR7.html
There are several interventions which we feel would benefit significantly from systematic reviews:
• Interventions to reduce the impact of electricity pylons and power lines
• Interventions to reduce seabird bycatch
• The provision of artificial nest sites
• The provision of supplementary food
Scope of the Bird Conservation synopsis
This synopsis covers evidence for the effects of conservation interventions for native (see below), wild birds.
It is restricted to evidence captured on the website www.conservationevidence.com. It includes papers published in the journal Conservation Evidence, evidence summarised on our database and systematic reviews collated by the Collaboration for Environmental Evidence.
We have gathered evidence from all around the world, and the apparent over (or under-representation) of some regions reflects the current biases in published research papers available to Conservation Evidence.
Native vs. non-native species
This synopsis does not include evidence from the substantial literature on husbandry of domestic birds, or non-native gamebirds (e.g. common pheasants Phasianus colchicus in Europe and North America). However, where these interventions affect native species, or are relevant to the conservation of native, wild species, they are included (e.g. management of farmland for common pheasants has a significant impact on several declining native songbirds in the UK, see Stoate (2002) in ‘Manage hedges to benefit wildlife’, ‘Plant nectar flower mixture/wildflower strips’, ‘Plant wild bird seed cover strips’, ‘Provide supplementary food for birds’, ‘Create beetle banks’, ‘Control predators not on islands – songbirds’, ‘Reduce pesticide or herbicide use generally’.
How we decided which conservation interventions to include
Our list of interventions has been agreed in partnership with an Advisory Board made up of international conservationists and academics with expertise in bird conservation. Although the list of interventions may not be exhaustive, we have tried to include all actions that have been carried out or advised to support populations or communities of wild birds.
How we reviewed the literature
In addition to evidence already captured by the Conservation Evidence project, we have searched the following sources for evidence relating to bird conservation:
• Fifteen specialist bird conservation journals, from their first publication to the end of 2010 (African Bird Club Bulletin, The Auk, Bird Conservation International, Bird Study, BTO Research Reports, Emu, Ibis, Journal of Avian Biology – formerly Ornis Scandinavica, Journal of Field Ornithology, Journal Raptor Research – formerly Raptor Research, Ornitologia Neotropical, RSPB Research Reports, The Condor, Waterbirds – formerly Colonial Waterbirds, Wilson Journal of Ornithology – formerly Wilson Bulletin)
• Twenty general conservation journals over the same time period.
• Where we knew of an intervention which we had not captured evidence for, we per-formed keyword searches on ISI Web of Science and www.scholar.google.com for this intervention.
Individual studies covered in this synopsis are all included in full or in summary on the Conservation Evidence website.
The criteria for inclusion of studies in the Conservation Evidence database are as follows:
• There must have been an intervention that conservationists would do
• Its effects must have been monitored quantitatively
In some cases, where a body of literature has strong implications for conservation of a particular species group or habitat, although it does not directly test interventions for their effects, we refer the reader to this literature, but present no evidence.
How the evidence is summarised
Conservation interventions are grouped primarily according to the relevant direct threats, as defined in the International Union for the Conservation of Nature (IUCN)’s Unified Classification of Direct Threats (www.iucnredlist.org/technical-documents/classification-schemes/habitats-classification-scheme-ver3). In most cases, it is clear which main threat a particular intervention is meant to alleviate or counteract.
Not all IUCN threat types are included, only those that threaten birds, and for which realistic conservation interventions have been suggested.
Some important interventions can be used in response to many different threats, and it would not make sense to split studies up depending on the specific threat they were studying. We have therefore separated out these interventions, following the IUCN’s Classification of Conservation Actions (http://www.iucnredlist.org/technical-documents/classification-schemes/conservation-actions-classification-scheme-ver2). The actions we have separated out are: ‘Habitat protection’, ‘Education and community development’, ‘Habitat restoration and creation’, ‘General responses to small/declining populations’ and ‘Captive breeding, rearing and releases (ex situ conservation)’. These respectively match the following IUCN categories: ‘Land/water protection’, ‘Education and awareness’ and ‘Livelihood, economic and other incentives’, ‘Land/water management – Habitat and natural process restoration’, and ‘Species Management’.
Normally, no intervention is listed in more than one place, and when there is ambiguity about where a particular intervention should fall there is clear cross-referencing. Some studies describe the effects of multiple interventions. When this is the case, cross-referencing is again used to direct readers to the other interventions investigated. Where a study has not separated out the effects of different interventions, the study is only described once, but readers are directed to it from the other interventions.
In the text of each section, studies are presented in chronological order, so the most recent evidence is presented at the end. The summary text at the start of each section groups studies according to their findings.
At the start of each chapter, a series of key messages provides a rapid overview of the evidence. These messages are condensed from the summary text for each intervention.
Background information is provided where we feel recent knowledge is required to interpret the evidence. This is presented separately and relevant references included in the reference list at the end of each intervention section.
References containing evidence for the effects of interventions are summarised in more detail on the Conservation Evidence website. In electronic versions of the synopsis, they are hyperlinked directly to the summary. If you do not have access to the electronic version of the synopsis, searching for the reference details or the species name on www.conservationevidence.com is the quickest way to locate summaries.
The information in this synopsis is available in three ways:
• As a book, printed by Pelagic Publishing and for sale from www.nhbs.com
• As a pdf to download from www.conservationevidence.com
• As text for individual interventions on the searchable database at www.conservation-evidence.com.
Terminology used to describe evidence
Unlike systematic reviews of particular conservation questions, we do not quantitatively assess the evidence, or weight it according to quality. However, to allow you to interpret evidence, we make the size and design of each trial we report clear. The table below defines the terms that we have used to do this.
The strongest evidence comes from randomised, replicated, controlled trials with paired-sites and before and after monitoring.
Term |
Meaning |
Site comparison |
A study that considers the effects of interventions by comparing sites that have historically had different interventions or levels of intervention. |
Replicated |
The intervention was repeated on more than one individual or site. In conservation and ecology, the number of replicates is much smaller than it would be for medical trials (when thousands of individuals are often tested). If the replicates are sites, pragmatism dictates that between five and ten replicates is a reasonable amount of replication, although more would be preferable. We provide the number of replicates wherever possible, and describe a replicated trial as ‘small’ if the number of replicates is small relative to similar studies of its kind. |
Controlled |
Individuals or sites treated with the intervention are compared with control individuals or sites not treated with the intervention. |
Paired sites |
Sites are considered in pairs, within which one was treated with the intervention and the other was not. Pairs of sites are selected with similar environmental conditions, such as soil type or surrounding landscape. This approach aims to reduce environmental variation and make it easier to detect a true effect of the intervention. |
Randomised |
The intervention was allocated randomly to individuals or sites. This means that the initial condition of those given the intervention is less likely to bias the outcome. |
Before-and-after trial |
Monitoring of effects was carried out before and after the intervention was imposed. |
Review |
A conventional review of literature. Generally, these have not used an agreed search protocol or quantitative assessments of the evidence. |
Systematic review |
A systematic review follows an agreed set of methods for identifying studies and carrying out a formal ‘meta-analysis’. It will weight or evaluate studies according to the strength of evidence they offer, based on the size of each study and the rigour of its design. All environmental systematic reviews are available at: www.environmentalevidence.org/index.htm |
Taxonomy
We have followed the taxonomy used in BirdLife International’s 2011 checklist (http://www.birdlife.org/datazone/info/taxonomy), updating the names used in original papers where necessary. We have always referred to the species name used in the original paper as well. Where possible, common names and Latin names are both given the first time each species is mentioned within each intervention.
Where interventions have a large literature associated with them we have sometimes divided studies along taxonomic or functional lines. These do not follow strict taxonomic divisions, but instead are designed to maximise their utility. For example, storks, herons and ibises are often included together as both groups are large wading birds and may respond to interventions in similar ways.
Habitats
Where interventions have a large literature associated with them and effects could vary between habitats, we have divided the literature using the IUCN Habitat Classification Scheme (Version 3.0), available from www.iucnredlist.org.
Significant results
Throughout the synopsis we have quoted results from papers. Unless specifically stated, these results reflect statistical tests performed on the results.
Multiple interventions
Many studies investigate several interventions at once. When the effects of different interventions are separated, then the results are discussed separately in the relevant sections. However, often the effects of multiple interventions cannot be separated. When this is the case, the study is included in the section on each intervention, but the fact that several interventions were used is highlighted.
How you can help to change conservation practice
If you know of evidence relating to bird conservation that is not included in this synopsis, we invite you to contact us, via the www.conservationevidence.com website. Following guidelines provided on the site, you can submit a summary of a previously published study, or submit a paper describing new evidence to the Conservation Evidence journal. We particularly welcome summaries written by the authors of papers published elsewhere, and papers submitted by conservation practitioners.