Collected Evidence: Collected Evidence: Provide supplementary food for rails and coots to increase reproductive success A small randomised and controlled trial in the USA found that fed American coots Fulica americana laid heavier eggs, but not larger clutches than controls. However, a randomised, replicated and controlled study in Canada found that clutch size, but not egg size was larger in fed American coot territories. There was also less variation in clutch size between fed territories. The Canadian study also found that coots laid earlier when fed, whilst a replicated cross-over trial from the UK found three was a shorter interval between  common moorhens Gallinula chloropus clutches in fed territories, but that fed birds were no more likely to produce second broods.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F528https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F528Sun, 09 Sep 2012 17:37:36 +0100Collected Evidence: Collected Evidence: Provide supplementary food for waders to increase reproductive successA small controlled trial from the Netherlands found that Eurasian oystercatchers Haematopus ostralegus did not produce larger replacement eggs if provided with supplementary food, and their eggs were, in fact smaller than the first clutch, whereas control females laid larger replacement eggs.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F529https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F529Sun, 09 Sep 2012 17:48:48 +0100Collected Evidence: Collected Evidence: Provide supplementary food for ibises to increase reproductive successA study from China found that breeding success of crested ibis Nipponia nippon was correlated with the amount of supplementary food provided, although no comparison was made with unfed nests.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F530https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F530Sun, 09 Sep 2012 17:51:49 +0100Collected Evidence: Collected Evidence: Provide supplementary food for owls to increase reproductive success Two replicated and controlled trials from Europe and the USA found that owls supplied with supplementary food had higher hatching and fledging rates than control pairs. The European study, but not the American, also found that fed pairs laid earlier  and had larger clutches The American study also found that owls were no more likely to colonise nest boxes provided with supplementary food.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F533https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F533Sun, 09 Sep 2012 19:15:10 +0100Collected Evidence: Collected Evidence: Provide supplementary food for kingfishers to increase reproductive successA controlled study in the USA found that belted kingfisher Ceryle alcyon supplied with food had heavier nestlings and were more likely to renest. There was mixed evidence for the effect of feeding on laying date.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F534https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F534Sun, 09 Sep 2012 19:30:18 +0100Collected Evidence: Collected Evidence: Provide supplementary food for pigeons to increase reproductive successA replicated cross-over study in the UK found no differences in reproductive parameters of European turtle doves Streptopelia turtur between years when food was supplied and those when it was not.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F535https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F535Sun, 09 Sep 2012 19:40:03 +0100Collected Evidence: Collected Evidence: Provide supplementary food to allow the rescue of a second chickA small controlled study in Spain found that second chicks from lammergeier Gypaetus barbatus nests survived longer if nests were provided with food, allowing one chick to be rescued.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F541https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F541Sat, 15 Sep 2012 20:58:36 +0100Collected Evidence: Collected Evidence: Provide supplementary food for gamebirds to increase adult survival Two European studies found increased numbers of grey partridge Perdix perdix in fed areas, compared to unfed areas. In one study there was no change in the overall population in the study area, in the second there was an increase. One cross-over study from the USA found that northern bobwhites Colinus virginianus had higher overwinter survival in fed areas, one found lower survival and a literature review found no overall effect of feeding.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F544https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F544Sun, 16 Sep 2012 09:01:06 +0100Collected Evidence: Collected Evidence: Provide supplementary food for cranes to increase adult survivalA before-and-after study from Japan and a global literature review found that local crane populations increased after the provision of supplementary food.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F547https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F547Sun, 16 Sep 2012 09:19:25 +0100Collected Evidence: Collected Evidence: Provide supplementary food for hummingbirds to increase adult survival Four studies from the USA found that three species of hummingbird showed preferences for higher concentrations of sucrose (measured in weight/volume), consuming more and visiting feeders more frequently. A study from the USA found that black-chinned hummingbirds Archilochus alexanderi preferentially fed on sugar solutions over artificial sweeteners, and that increasing the viscosity of these solutions (so they appeared more like sugar solutions) did not affect their consumption. Two studies from Mexico (ex situ) and Argentina found that four species showed preferences for sucrose over fructose or glucose when equiweight solutions were compared.  One found that birds also preferentially fed on sucrose over a sucrose-glucose mix, the other found no preference for sucrose over a glucose-fructose mix. A controlled study from the USA found that Anna’s hummingbirds Calypte anna showed a preference for red-dyed sugar solutions over five other colours, but only if different colours were presented at the same time. A replicated study from the USA found that rufous hummingbirds Selasphorous rufus preferentially fed on feeders placed higher, over lower ones.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F550https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F550Sun, 16 Sep 2012 09:33:20 +0100Collected Evidence: Collected Evidence: Provide supplementary food for nectar-feeding songbirds to increase adult survival Two studies from Australia and New Zealand found that ten species of honeyeaters and stitchbirds Notiomystis cincta readily used feeders supplying sugar solutions, with seasonal variations varying between species and stitchbirds spending more time foraging for insects when food was supplied. A series of ex situ trials using southern African birds found that most species tested showed a preference for sucrose solutions over glucose or fructose. One study found that sunbirds and sugarbirds only showed such a preference at low (equimolar) concentrations. Two more studies found that two species showed preferences for sucrose when comparing 20% (by weight) solutions, although a third species did not show this preference. All species rejected solutions with xylose (a natural sugar in nectar) added. A final study found that sucrose preferences only became apparent at equicalorific concentrations high enough for birds to subsist on.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F553https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F553Sat, 22 Sep 2012 20:11:36 +0100Collected Evidence: Collected Evidence: Can supplementary feeding increase predation or parasitism? A replicated, controlled study in the USA found that providing seeds in predictable areas did not increase predation on seven species of songbird. A replicated and controlled trial in Spain found higher levels of potentially dangerous gut microflora when fed on livestock carrion, compared to those fed on wild rabbits. A replicated study in Spain found higher levels of predation on artificial nests close to carcasses provided for vultures.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F554https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F554Sat, 22 Sep 2012 20:37:07 +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%2Fconservationevidencejournal.com%2Factions%2F555https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F555Sat, 22 Sep 2012 20:40:45 +0100Collected Evidence: Collected Evidence: Translocate petrels and shearwatersTwo studies from Australia and one from New Zealand found that colonies of burrow-nesting Procellariiformes were successfully established on two islands, and in uninhabited areas of another following the translocation and hand-rearing of chicks.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F568https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F568Sun, 30 Sep 2012 12:54:24 +0100Collected Evidence: Collected Evidence: Use captive breeding to increase or maintain populations of pigeonsA review of a captive-breeding programme on Mauritius and in the UK found that 42 pink pigeons, Nesoenas mayeri, were successfully bred in captivity.Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F597https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F597Sat, 13 Oct 2012 15:21:33 +0100Collected Evidence: Collected Evidence: Artificially incubate and hand-rear seabirds in captivity Five studies from across the world found evidence for the success of hand-rearing seabirds. One small study in Spain found that one of five hand-reared Audouin’s gulls Larus audouinii successfully bred in the wild. Four studies found that various petrel species (Procellariiformes) successfully fledged after hand-rearing. One controlled study found that fledging rates of hand-reared birds was similar to parent-reared birds, although a study on a single bird found that the chick fledged at a lower weight and later than parent-reared chicks.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F604https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F604Sat, 13 Oct 2012 16:50:42 +0100Collected Evidence: Collected Evidence: Artificially incubate and hand-rear vultures in captivityA study in Peru found that hand-reared Andean condors Vultur gryphus had similar survival to parent-reared birds after release into the wild.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F613https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F613Sun, 14 Oct 2012 12:01:57 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of wildfowl Two studies of reintroduction programmes of ducks in New Zealand found high survival of released birds and population establishment, with one describing successful breeding. One study describes higher success in the second year of the release programme, potentially because there was then a population present in the wild and more intensive predator control. A before-and-after study from Alaska found low survival of released cackling geese Branta hutchinsii, but that the population recovered from 1,000 to 6,000 birds after releases and the control of mammalian predators. A review of a reintroduction programme from Hawaii found that the release of 2,150 Hawaiian geese (nene) Branta sandvicensis had not resulted in the establishment of a self-sustaining population, although some birds bred. Two studies from Canada found very low return rates for released ducks with one finding no evidence for survival of released birds over two years, although there was some evidence that breeding success was higher for released birds than wild ones. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F618https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F618Sun, 14 Oct 2012 13:05:11 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of vultures Four studies of two release programmes found that release programmes led to large population increases in Andean condors Vultur gryphus in Colombia and griffon vultures Gyps fulvus in France. A small study in Peru found high survival of released Andean condors Vultur gryphus over 18 months, with all fatalities occurring in the first six months after release.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F625https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F625Sun, 14 Oct 2012 14:40:59 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of pigeonsA single review of a captive-release programme in Mauritius found that that released pink pigeons Nesoenas mayeri had a first year survival of 36%.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F628https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F628Sun, 14 Oct 2012 22:54:33 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of songbirds A before-and-after study in Mauritius describes the establishment of a population of Mauritius fody Foudia rubra following the release of captive-bred individuals. Four studies of three release programmes on Hawaii found high survival of all three species released (Hawaiian crows Corvus hawaiiensis and two thrushes: omao Myadestes obscurus and puaiohi M. palmeri), with the two thrushes successfully breeding. The authors in one note that many of the released puaiohi dispersed from the release site, meaning that repopulating specific areas may require multiple releases. A replicated, controlled study from the USA found that San Clemente loggerhead shrike Lanius ludovicianus mearnsi pairs with captive-bred females had lower reproductive success than pairs where both parents were wild-bred.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F630https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F630Sun, 14 Oct 2012 23:05:39 +0100Collected Evidence: Collected Evidence: Provide monetary benefits to local communities for sustainably managing their forest and its wildlife (e.g. REDD, employment) One before-and-after study in Belize found that numbers of black howler monkeys increased by 138% over 13 years after local communities received monetary benefits, alongside other interventions. One before-and-after study in the Republic of Congo found that most central chimpanzees reintroduced to an area where local communities received monetary benefits, alongside other interventions, survived over five years. One before-and-after study in Rwanda, Uganda and the Democratic Republic of Congo found that numbers of mountain gorillas declined by 28% over 41 years despite the implementation of development projects in nearby communities, alongside other interventions. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F1509https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F1509Wed, 18 Oct 2017 15:15:52 +0100Collected Evidence: Collected Evidence: Provide non-monetary benefits to local communities for sustainably managing their forest and its wildlife (e.g. better education, infrastructure development) One before-and-after study in the Republic of Congo found that 70% of the central chimpanzees reintroduced to an area where local people were provided non-monetary benefits, alongside other interventions, survived over seven years. One before-and-after study in India found that numbers of hoolock gibbons increased by 66% over five years after providing local communities with alternative income, alongside other interventions. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F1510https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F1510Wed, 18 Oct 2017 15:39:00 +0100Collected Evidence: Collected Evidence: Permanent presence of staff/manager One before-and-after study in Kenya found that numbers of Tana River red colobus and crested mangabeys decreased despite permanent presence of reserve staff, alongside other interventions. One study in Thailand found that a reintroduced population of lar gibbons declined over three years despite permanent presence of reserve staff alongside other interventions. One before-and-after study in Belize found that numbers of black howler monkeys increased by 138% over 13 years after introducing permanent presence of reserve staff, alongside other interventions. One before-and-after study in Congo found that most reintroduced central chimpanzees survived over five years after being accompanied by reserve staff, alongside other interventions. One before-and-after study in Gabon found that most reintroduced western lowland gorillas survived over nine months, after being accompanied by reserve staff, alongside other interventions. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F1517https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F1517Thu, 19 Oct 2017 09:22:48 +0100Collected Evidence: Collected Evidence: Regularly provide supplementary food to primates during resource scarce periods only One before-and-after study in the Republic of Congo found that the majority of chimpanzees survived for at least five years after supplementary feeding in resource scarce periods, alongside other interventions. One before-and-after study in Kenya found that wild olive baboons survived for at least 17 years after supplementary feeding in drought periods soon after translocation, alongside other interventions. One controlled study in Madagascar found that the diet of black-and-white ruffed lemurs was similar to that of wild individuals after supplementary feeding in resource scarce periods, alongside other interventions. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F1527https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F1527Thu, 19 Oct 2017 09:59:24 +0100
What Works 2021 cover

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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