Collected Evidence: Collected Evidence: Increase the proportion of natural/semi-natural vegetation in the farmed landscape Of four studies captured, one, a replicated and controlled paired sites study from Australia, found that farms with plantings of native vegetation held more species than those without. The effect was smaller than that explained by variation in the amount of natural habitat remaining on farms. A replicated study from Switzerland found more species in areas under the Ecological Compensation Area scheme than areas not under it. A before-and-after study from Switzerland found that the populations of three bird species increased after an increase in the amount of land under the Ecological Compensation Scheme. This study found that three species were more found more than expected on Ecological Compensation Scheme land. Another replicated study from Switzerland found that some habitats held more birds if they were close to ECA habitat but that the amount of Ecological Compensation Scheme in an area had no impact on population densities. A small study from the UK found no effect of habitat creation on grey partridge populations. Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F171https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F171Sun, 20 May 2012 13:21:01 +0100Collected Evidence: Collected Evidence: Undersow spring cereals, with clover for example Three studies from the UK, two replicated, found that there were higher densities of some study species on undersown fields or margins, compared with other fields, or that use of fields increased after they were undersown. One of these (reported in two places) found that not all species nested at higher densities. One replicated study from the UK found that various measures of grey partridge population health declined as the amount of undersown cereal on sites increased. A replicated study from the UK found no relationship between the amount of undersown cereals on a site and the productivity of grey partridge on that site.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F208https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F208Sun, 15 Jul 2012 17:28:25 +0100Collected 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: Delay haying/mowing Two reviews from the UK found that the population of corncrakes Crex crex increased following the implementation of two initiatives to encourage farmers to delay mowing (and provide cover and use corncrake-friendly techniques). A replicated and controlled paired sites study from the Netherlands found no evidence that waders and other birds were more abundant in fields with delayed mowing, compared to paired controls. A replicated and controlled before-and-after study from the Netherlands found that fields with delayed mowing held more birds than controls, but did so before the start of the scheme. Population trends did not differ between treatments. A replicated, controlled study from the USA found that destruction of nests by machinery was lower and late-season nesting higher in late-cut fields, compared with early-cut fields.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F223https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F223Tue, 17 Jul 2012 14:29:48 +0100Collected Evidence: Collected Evidence: Disturb birds at roosts One controlled study from the USA investigated the effects of harassment on fish predation, and found there were fewer double-crested cormorants Phalacrocorax auritus on, and fewer fish were taken from, fish ponds near roosts which were harassed, compared with undisturbed roosts. A review found that there was a reduction in the number of cormorants foraging near roosts after night-time disturbance. Four studies, two replicated, from the USA and Israel, found that cormorants moved away from roosts where they were disturbed at night. One study found that this effect was only temporary.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F245https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F245Wed, 18 Jul 2012 11:42:12 +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: Use prescribed burning on savannas A replicated and controlled study from Kenya, of five studies captured, found that burned areas of savanna tended to have more birds and more species than control or grazed areas. However, the authors note that differences were not present during drought years and burned sites showed significant annual variation, unlike grazed sites. A replicated and controlled study from Australia found that the effects of burning on bird abundances depended on burn season, and habitat type. Two replicated studies in the USA found that some open country species were more common in burned areas than unburned, whilst other species were less so. A small study from the USA found that two eastern bluebird Sialia sialis successfully raised chicks after the habitat around their nest boxes was subject to a prescribed burn.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F320https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F320Thu, 26 Jul 2012 14:58:00 +0100Collected Evidence: Collected Evidence: Use ring-barking (girdling), cutting or silvicides to produce snags Of five studies found, one replicated and controlled study from the USA found that forest plots provided with snags had higher bird diversity and abundance than plots without snags added. Three studies from the USA and UK found that woodpeckers and other species used artificially-created snags for nesting and foraging. One study from the USA found that use increased with how long a snag had been dead. A UK study found that no crested tits used snags created for them, possibly because they were not rotted enough, or because they were too close to the ground.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F343https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F343Sat, 28 Jul 2012 20:29:12 +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: Control mammalian predators on islands for songbirds Two before-and-after trials in the Seychelles and Cook Islands describe population increases in magpie robins and monarch flycatchers following cat and rat control. A before-and-after study from New Zealand found that the population of South Island robins Petroica australis australis was almost identical before and after rat control. Two studies found higher reproductive success in monarch flycatchers and shrikes in areas with rodent control, compared to areas without control. However, this was climate dependent in shrikes. A before-and-after study from Hawaii found lower predation on artificial nests after intensive rodent control.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F382https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F382Wed, 08 Aug 2012 14:43:04 +0100Collected Evidence: Collected Evidence: Control predators not on islands for gamebirds Four controlled studies in Europe found increased populations or productivity of grouse and partridges on sites with predator removal. One study tested multiple interventions simultaneously. A fifth replicated UK study found no increase in grouse densities or reproductive success on sites with gamekeepers, compared to those without.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F387https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F387Wed, 08 Aug 2012 17:25:00 +0100Collected Evidence: Collected Evidence: Physically protect nests with individual exclosures/barriers or provide shelters for chicks of songbirds Three studies from across the world found increased fledging success for nests in trees protected by individual barriers. A replicated controlled study from the USA also found higher success for ground-nests protected by individual barriers. Two studies from the UK and Japan found lower predation rates on nests protected by individual barriers.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F400https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F400Thu, 16 Aug 2012 13:13:40 +0100Collected Evidence: Collected Evidence: Use artificial nests that discourage predation Three trials in North America found lower predation or higher nesting success of wildfowl in nest boxes or nesting ‘tubs’ than natural nests in tree cavities or on the ground. A trial in captivity found that raccoons could be prevented from entering nest boxes if they were topped with a metal cone with a 7.6 cm overhang and the distance between entrance hole and the roof was increased from 30 to 60 cm. A replicated study in the USA found that fewer woods duck Aix sponsa used nest boxes with predator guards on when given the choice of unaltered boxes, but that both designs were used with equal frequency when only one design was available.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F402https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F402Thu, 16 Aug 2012 14:40:11 +0100Collected Evidence: Collected Evidence: Can nest protection increase predation of adults and chicks? Three replicated and controlled studies from North America and Sweden found higher levels of predation on adult birds with nest exclosures, one study from Sweden found that predation was no higher. A replicated and controlled study from Alaska found that long-tailed jaegers Stercorarius longicaudus learned to associate exclosures with birds, targeting adult western sandpipers Calidris mauri and quickly predating chicks when exclosures were removed.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F403https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F403Thu, 16 Aug 2012 14:45:33 +0100Collected Evidence: Collected Evidence: Use aversive conditioning to reduce nest predation by mammalian predators One study from the USA and three  ex situ experiments found evidence for lower consumption of eggs treated with repellent chemicals. However, when untreated eggs were provided simultaneously with or after treated eggs, no studies found evidence for continued lower predation. I.e. aversive conditioning did not occur. In addition, a study from the USA found no effect of repellent chemicals on predation rates of genuine nests.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F419https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F419Fri, 17 Aug 2012 16:10:42 +0100Collected Evidence: Collected Evidence: Provide supplementary food for vultures to increase reproductive success Two before-and-after studies from the USA and Greece found that there were population increases in local populations of two vultures (one New World, one Old World) following the provision of food in the area. A study from Israel found that a small, regularly supplied feeding station could provide sufficient food for breeding Egyptian vultures Neophron percnopterus. A before-and-after study from Italy found that a small population of Egyptian vultures Neophron percnopterus declined following the provision of food at a feeding station, and only a single vulture was seen at the feeding station.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F531https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F531Sun, 09 Sep 2012 18:08:42 +0100Collected Evidence: Collected Evidence: Provide supplementary food through the establishment of food populations One pre-1950 study in the USA found that waterfowl fed on specially-planted rye grass. Three studies from North America and Sweden found that attempts to support populations by establishing prey did not succeed. Whooping cranes Grus americana in the USA preferentially fed on scattered grains, over planted crops; attempts in Sweden to boost macroinvertebrate numbers were not successful and great horned owls Bubo virginianus in Canada did not respond to induced increases in prey populations.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F555https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F555Sat, 22 Sep 2012 20:40:45 +0100Collected Evidence: Collected Evidence: Use perches to increase foraging success Two studies from the USA found that raptors and other birds used perches provided, whilst a replicated and controlled study in Sweden found that raptors used clearcuts with perches significantly more than those without. However, a controlled study from the USA found that overall bird abundances were not higher in areas provided with perches and a small controlled cross-over trial on an island in the USA found that San Clemente loggerhead shrikes Lanius ludovicianus mearnsi did not alter their hunting patterns or increase their success rates following the installation of perches in their territories.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F556https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F556Sun, 23 Sep 2012 15:05:36 +0100Collected Evidence: Collected Evidence: Use captive breeding to increase or maintain populations of bustards We captured four studies of a houbara bustard, Chlamydotis undulata, macqueenii captive breeding programme in Saudi Arabia. The project successfully raised chicks in captivity, with 285 chicks hatched in the 7th year of the project after 232 birds were used to start the captive population. Captive birds bred earlier and appeared to lay more eggs than wild birds. Forty-six percent of captive eggs hatched and 43% of chicks survived to ten years old, although no comparison was made with wild birds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F592https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F592Sat, 06 Oct 2012 23:13:15 +0100Collected Evidence: Collected Evidence: Use captive breeding to increase or maintain populations of storks and ibises We captured a small study and a review describing the captive breeding of storks (Ciconiidae) and a study and a review describing the breeding of northern bald ibis, Geronticus eremita. Both studies on storks were from the USA. The small study found that a pair bred; the review found that only seven of 19 species had been successfully bred in captivity. A review of bald ibis conservation found that 1,150 birds had been produced in captivity from 150 founders over 20 years. However, some projects had failed, and a study from Turkey found that captive birds had lower productivity than wild birds.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F595https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F595Sat, 13 Oct 2012 14:54:55 +0100Collected Evidence: Collected Evidence: Artificially incubate and hand-rear waders in captivity Three out of four replicated and controlled studies from the USA and New Zealand found that artificially incubated and/or hand-reared waders had higher hatching and fledging success than controls. One study from New Zealand found that hatching success of black stilt Himantopus novaezelandiae was lower for artificially-incubated eggs.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F611https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F611Sat, 13 Oct 2012 18:03:08 +0100Collected Evidence: Collected Evidence: Artificially incubate and hand-rear parrots in captivity Two studies from South America describe the successful hand-rearing of parrot chicks, with ten of 12  yellow-shouldered amazons Amazona barbadensis surviving for a year after release and blue-fronted amazons Amazona aestiva fledging at higher weights than wild birds. A review of the kakapo Strigops habroptilus management programme found that chicks could be successfully raised and released, but that eggs incubated from a young age had low success. A study from the USA found that all hand-reared thick-billed parrots Rhynchopsitta pachyrhyncha died within a month of release: significantly lower survival than for wild-caught birds also translocated to the release site.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F615https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F615Sun, 14 Oct 2012 12:29:14 +0100Collected Evidence: Collected Evidence: Artificially incubate and hand-rear songbirds in captivity Four studies from the USA found high rates of success for artificial incubation and hand-rearing of songbirds. The one study to compare techniques found that crow chicks fed more food had higher growth rates, but that these rates never matched those of wild birds.    Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F616https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F616Sun, 14 Oct 2012 12:34:18 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of bustards Three reviews of a release programme for houbara bustard Chlamydotis undulata macqueenii in Saudi Arabia and a replicated trial as part of the same programme found low initial survival of released birds, but the establishment of a breeding population and an overall success rate of 41%. The programme tested many different release techniques, discussed elsewhere, with releases being most successful if sub-adults were released, able to fly, into a large exclosure.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F622https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F622Sun, 14 Oct 2012 14:23:17 +0100Collected Evidence: Collected Evidence: Clip birds’ wings on release Two studies from Saudi Arabia and Hawaii found that bustards and geese had lower survival when released in temporary exclosures with clipped wings, compared to birds released with unclipped wings. A review of cackling goose Branta hutchinsii conservation found that wing-clipped or moulting wild adult geese proved a better strategy than releasing young geese. A review of northern bald ibis (waldrapp) Geronticus eremita conservation found no differences in survival between birds released with clipped and unclipped wings in Israel.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F633https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F633Sun, 14 Oct 2012 23:29:34 +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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