Collected Evidence: Collected Evidence: Revert arable land to permanent grassland All five studies looking at the effects of reverting arable land to grassland found no clear benefit to birds. The studies monitored birds or grey partridges in the UK and wading birds in Denmark (4). They included three replicated controlled trials. One of the studies, a controlled before-and-after study from the UK, showed that grey partridge numbers fell significantly following the reversion of arable fields to grassland.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F210https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F210Sun, 15 Jul 2012 18:00:36 +0100Collected Evidence: Collected Evidence: Scare birds from fish farms One before-and-after study from Israel found that the population of pygmy cormorants in the area increased after birds were scared away from fish farms, possibly due to lower persecution. One of two studies that examined fish stocks found that fewer fish were taken from a farm when heron distress calls were played. The other study, a literature review, found no evidence for the effects of scaring birds on fish stocks. Two replicated studies from Belgium and Australia found that using foot patrols to disturb birds from fish farms did not reduce the number of birds present or fish consumption. Ten of eleven studies from across the world, three controlled, found evidence that playing distress calls or using other acoustic deterrents (some with flashes of light) reduced the number of birds at fish farms, or changed bird behaviours. One of these involved underwater broadcasting. One study found effects were only temporary and five found that birds became habituated to noises. Four studies, one replicated and controlled, two before-and-after, found that acoustic deterrents were not effective in scaring birds. Five of seven studies, one controlled, found evidence that visual deterrents (including inflatable ‘Scarey Man’ scarecrows) reduced the number of birds at fish farms. Three found evidence for habituation to deterrents and three studies found no evidence that visual deterrents were effective. Two studies examined other deterrents, finding that trained raptors were effective but that the effects of helicopters and ultra-light aircraft were either inconclusive or very temporary.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F244https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F244Wed, 18 Jul 2012 11:00:04 +0100Collected Evidence: Collected Evidence: Scare or otherwise deter birds from airports Two replicated studies in the UK and USA found that fewer birds (mainly gulls Larus spp.) used areas of long grass at airports. However, no data were provided on the effect of long grass on strike rates or mortality of birds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F261https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F261Thu, 19 Jul 2012 13:26:20 +0100Collected Evidence: Collected Evidence: Scare fish-eating birds from areas to reduce conflictStudies investigating scaring birds from fishing areas are discussed in ‘Threat: Agriculture – Aquaculture’.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F282https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F282Tue, 24 Jul 2012 13:00:53 +0100Collected Evidence: Collected Evidence: Set longlines at night to reduce seabird bycatch Six out of eight studies from fisheries around the world found lower rates of seabird bycatch on longlines set at night, compared with during the day, or with previously collected data. However, effects seemed to depend on the species caught. Two studies found higher rates of bycatch on night-set longlines, due to high numbers of white-chinned petrels Procellaria aequinoctialis or northern fulmars Fulmarus glacialis being caught at night.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F283https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F283Tue, 24 Jul 2012 13:04:04 +0100Collected Evidence: Collected Evidence: Set lines underwater to reduce seabird bycatch Four replicated and controlled studies and a literature review in Norway, South Africa and the North Pacific found reductions in northern fulmar Fulmarus glacialis, albatross and petrel bycatch rates when using an underwater setting funnel. Although one found a disproportionate number of albatross were caught during day line setting. A replicated and controlled study found that underwater setting increased attack rates of shearwaters Puffinus spp. on longlines and did not reduce bycatch.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F288https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F288Tue, 24 Jul 2012 16:38:44 +0100Collected Evidence: Collected Evidence: Set longlines at the side of the boat to reduce seabird bycatch We found no evidence for the effects on seabird bycatch rates of setting longlines from the side of the boat. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F289https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F289Tue, 24 Jul 2012 16:44:03 +0100Collected Evidence: Collected Evidence: Replace non-native species of tree/shrubA replicated, controlled study from the USA found that the number of black-chinned hummingbird nests increased at sites with fuel reduction and planting of native species, but that the increase was smaller than at sites without planting.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F341https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F341Sat, 28 Jul 2012 20:22:33 +0100Collected Evidence: Collected Evidence: Restore or create forests Thirteen of 15 studies from across the world found that bird communities in restored forests were similar to original forests or that species returned to restored sites, that species recovered significantly better than ats unrestored site, that species richness, diversity or abundances increased over time or that restoration techniques themselves improved over time. Nine of the studies found that some species did not return to restored sites, or were less common than in original forests.  One study also found that overall territory density decreased over time and another found that territory densities were similar between sites planted with oak Quercus spp. saplings and unplanted sites. One study from the USA found that productivity of birds was similar in restored and natural forests. Another found that productivity was lower. A study from the USA found that fast-growing cottonwood forests less than ten years old held more territories and had higher diversity than similarly-aged oak forests.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F360https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F360Mon, 30 Jul 2012 16:58:06 +0100Collected Evidence: Collected Evidence: Restore or create grasslands Of 23 studies found, three from the USA, Canada and Iceland found that species richness on restored grassland sites was similar to remnant habitats or higher than unrestored sites. One replicated, randomised study from the USA found that bird diversity was lower on restored grassland sites compared to hayfields or pastures, whilst a small American study found that species richness declined at one of two fields restored to grassland from croplands. Three studies from the USA found that target species used restored grasslands. Two studies from the USA found that CRP fields held disproportionate proportions of total bird populations, or that local population trends were correlated with the amount of CRP land in the area. Six studies from the USA and UK found that the abundances or densities of some, or all, species were higher on restored sites compared to unrestored sites, or were comparable to natural habitats. Two studies found lower abundances of species on restored sites compared to unrestored sites, although the authors of one suggest that drought conditions may have confounded the results. Five studies from the USA found that at least some bird species in restored areas of grassland had higher productivities than birds in unrestored areas; similar or higher productivies than natural habitats; or had high enough productivities to sustain populations. Three studies found that productivities were lower in restored areas than unrestored, or that productivities on restored sites were too low to sustain populations. A replicated study from the USA found that older CRP fields held more nests, but fewer species than young fields. Two replicated American studies found no differences in species richness or abundances between CRP fields and riparian filter strips whether they were sown with warm- or cool-season grasses, whilst another found that more grassland specialist species were found on sites sown with non-native species. A replicated study from the USA found no difference in bird densities between sites seeded with redtop grass and those not seeded. A study from Iceland found that very few birds were found on restored sites, unless they were sown with Nootka lupin.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F361https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F361Tue, 31 Jul 2012 13:44:05 +0100Collected Evidence: Collected Evidence: Restore or create traditional water meadows Four out of five before-and-after studies, all from the UK, found that the number of waders and wildfowl on sites increased following the restoration of water meadows. One before-and-after study from Sweden found no increase in northern lapwing population following an increase in the area of managed meadows in the study area. This study also found that restored meadows were used less than expected by breeding lapwings. A before-and-after study from Sweden found that hatching success of northern lapwings were higher on meadows than on spring-sown crops. There were no differences between meadows and autumn-sown crops or grasslands.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F363https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F363Mon, 06 Aug 2012 12:51:09 +0100Collected Evidence: Collected Evidence: Restore or create shrubland Only one of the four studies captured investigated the effects of shrubland restoration in isolation. This small before-and-after study from the UK found that one or two pairs of northern lapwing bred on an area of restored moorland, whereas none had previously bred in the area. A study from the USA and one from the Azores found that populations of target species (gamebirds and seabirds) increased following shrubland restoration, amongst other interventions. A replicated study from the UK which did not distinguish between several interventions performed found a negative relationship between the combined intervention and the ratio of young-to-old grey partridges.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F364https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F364Mon, 06 Aug 2012 13:03:08 +0100Collected Evidence: Collected Evidence: Restore or create savannas We found no evidence for the effects of savanna restoration or creation on bird populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F365https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F365Mon, 06 Aug 2012 13:10:27 +0100Collected Evidence: Collected Evidence: Restore or create inland wetlands Of eleven studies captured, 11, from the mainland USA, Guam, Canada and Hawaii, found that birds used artificially restored or created wetlands. Two found that rates of use and species richness were similar or higher than on natural wetlands. One found that use rates were higher than on unrestored wetlands. Three studies from the USA and Puerto Rico found that restored wetlands held lower densities and fewer species of birds than natural wetlands. A replicated study from the USA found that least bittern productivity was similar in restored and natural wetlands. Two replicated studies examined wetland characteristics: one from the USA found that semi-permanent restored wetlands were used more than temporary or seasonal ones. A study from Hawaii found that larger restored wetlands were used more than smaller sites.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F366https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F366Mon, 06 Aug 2012 13:34:38 +0100Collected Evidence: Collected Evidence: Restore or create coastal and intertidal wetlands All six studies found, from the USA and UK, found that target bird species used restored or created wetlands. Two found that numbers and/or diversity were at least as high as in natural wetlands, one that numbers were higher than in unrestored sites. Three found that bird numbers on wetlands increased over time. Two studies from the UK found that songbirds and waders decreased following wetland restoration, whilst a study from the USA found that songbirds were more common on unrestored sites than restored wetlands.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F367https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F367Tue, 07 Aug 2012 13:15:07 +0100Collected Evidence: Collected Evidence: Restore or create kelp forestsA before-and-study in the USA found that the densities of five of the nine bird species analysed increased following kelp forest restoration.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F368https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F368Tue, 07 Aug 2012 13:39:18 +0100Collected Evidence: Collected Evidence: Restore or create lagoonsA before-and-after study in the UK found that large numbers of bird species used, and bred, in a newly-created lagoon.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F369https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F369Tue, 07 Aug 2012 13:47:37 +0100Collected Evidence: Collected Evidence: Revegetate gravel pits We found no evidence for the effects of gravel pit revegetation on bird populations. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F370https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F370Tue, 07 Aug 2012 13:49:46 +0100Collected Evidence: Collected Evidence: Remove/treat endoparasites and diseases Three studies from across the world investigating a range of taxa and parasites found that birds had higher productivity or survival if either chicks or adults were treated for endoparasites. One small study from Spain found no effect of Staphylococcus aureus treatment on eagle survival, while a study from Mauritius found uncertain evidence as to whether trichomoniasis treatment increased survival of pink pigeons Nesoenas mayeri after fledging. A randomised, replicated and controlled trial from the Netherlands found lower parasite burdens but also lower survival in Eurasian oystercatcher Haematopus ostralegus chicks treated with anthelmintic drugs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F434https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F434Wed, 22 Aug 2012 14:54:24 +0100Collected Evidence: Collected Evidence: Remove/treat ectoparasites to increase survival or reproductive success We found no evidence on the effects of removing/treating ectoparasites to increase survival or reproductive success. 'No evidence' for an action means we have not yet found any studies that directly and quantitatively tested this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F436https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F436Wed, 22 Aug 2012 15:22:12 +0100Collected Evidence: Collected Evidence: Remove/control adult brood parasites All 11 studies from across the world that investigated parasitism rates found that they were lower following cowbird Molothrus spp. control. One study from Ecuador found an increase in host species population after cowbird control, but two American studies found no such effect. Five studies from the Americas found higher productivities or success rates of host nests when cowbirds were removed, five found that at least some measures of productivity did not change with cowbird control.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F441https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F441Thu, 23 Aug 2012 14:28:02 +0100Collected Evidence: Collected Evidence: Restrict certain pesticides or other agricultural chemicals for birdsA small scale study found that Pyrazophos reduced chick food abundance more than other foliar fungicides. A before-and-after study from Spain found that the population of griffon vultures Gyps fulvus increased in the study area following multiple interventions including the banning of strychnine.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F455https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F455Wed, 29 Aug 2012 14:24:27 +0100Collected Evidence: Collected Evidence: Replace nesting substrate following severe weatherTwo before-and-after studies from Canada found that common tern Sterna hirundo populations increased at one colony where nesting substrates were replaced, but decreased at a second. Several other interventions were used at both sites, making it difficult to evaluate the effects of substrate replacement.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F474https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F474Thu, 30 Aug 2012 12:47:05 +0100Collected Evidence: Collected Evidence: Repair/support nests to support breedingA small study from Puerto Rico found that nine Puerto Rican parrot Amazona vittata nests were repaired, resulting in no chicks dying of cold.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F502https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F502Tue, 04 Sep 2012 16:31:27 +0100Collected Evidence: Collected Evidence: Remove vegetation to create nesting areas Two out of six studies found that the number of waders and terns nesting in an area increased following the removal of vegetation, and another found that a tern colony moved to an area prepared by removing vegetation. Two of these studies used multiple interventions at once. One study found a decrease in colony size after several interventions, including vegetation control. A study from the UK found that gulls and terns nested in an area cleared of vegetation and a controlled study from Puerto Rico found that although no terns nested in plots cleared completely of vegetation, more nested in partially-cleared plots than in uncleared plots. A before-and-after study from Canada found that tern nesting success was higher after plots were cleared of vegetation and other interventions were used.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F505https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F505Thu, 06 Sep 2012 14:00:49 +0100
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What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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