Collected Evidence: Collected Evidence: Mark or tint windows to reduce collision mortality Two randomised, replicated and controlled studies (one ex situ) found that marking windows did not appear to reduce bird collisions. However, when windows were largely covered with white cloth, fewer birds flew towards them. A randomised, replicated and controlled study found that fewer birds collided with tinted windows than with un-tinted ones, although the authors noted that the poor reflective quality of the glass could have influenced the results. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F167https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F167Sat, 19 May 2012 20:22:28 +0100Collected Evidence: Collected Evidence: Pay farmers to cover the costs of bird conservation measures Three reviews from the UK of three studies captured reported population increases of three species after the introduction of specially-designed agri-environment schemes. These species were cirl buntings, corncrakes and Eurasian thick-knees. One of these found that many other species continued to decline. Twenty-two of 25 studies all from Europe, including a systematic review,  examining local population levels or densities found that at least some birds studied were at higher densities, had higher population levels or more positive population trends on sites with agri-environment schemes, compared to non-agri-environment scheme sites. Some studies found that differences were present in all seasons, others in either summer or winter. Fifteen studies from Europe, including a systematic review, found that some or all species were not found at higher densities, had similar or lower population levels, showed similar population trends on sites with agri-environment schemes, compared with non-agri-environment scheme sites, or showed negative population trends. A study from the Netherlands found that many agri-environment scheme farms were sited in areas where they were unlikely to be effective. One small study from the UK found no differences between winter densities of seed-eating birds on UK Higher Levels Stewardship sites, compared with those under Entry Level Stewardship. A replicated study from the UK found that grey partridge survival was higher on agri-environment scheme sites than non-scheme sites. This difference was not significant every year. Two of three studies investigating reproductive productivity, including one replicated study, found that productivity was higher on farms under agri-environment schemes. One replicated study from the UK found no effect of agri-environment schemes on productivity. A review (Vickery et al. 2010) found that the amount of land entering an agri-environment scheme was on target, but that some options were not being used at high enough rates to help many species. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F172https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F172Sun, 20 May 2012 14:06:41 +0100Collected Evidence: Collected Evidence: Provide or retain set-aside areas in farmland Three replicated studies and a review of five studies from Europe and North America examining species richness or diversity found that more species were found on set-aside than on crops. One found fewer species on set-aside than other agricultural habitats. All 21 studies, including a systematic review, 12 replicated experiments and two reviews, from Europe and North America that investigated population trends or habitat associations found that some species were found at higher densities or used set-aside more than other habitats, or were found on set-aside. Four studies (three replicated) from the UK found that some species were found at lower densities on set-aside compared to other habitats. Three of four replicated studies from the UK found that waders and Eurasian skylarks had higher productivities on set-aside, compared to other habitats. One study found that skylarks nesting on set-aside had lower productivity compared to those on cereal crops, and similar productivities to those on other crops. One replicated paired study from the UK found that rotational set-aside was used more than non-rotational set-aside, a replicated paired study found no differences between rotational and non-rotational set-aside. A review from Europe and North America found that naturally regenerated set-aside held more birds and more species than sown set-aside. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F175https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F175Sun, 27 May 2012 15:10:59 +0100Collected Evidence: Collected Evidence: Plant wild bird seed or cover mixture All seven studies (based on five replicated experiments and a review) that investigated species richness or diversity were from the UK and found that fields or farms with wild bird cover had higher bird diversity than those without, or that more species were found in wild bird cover than in surrounding habitats. Thirty-two studies out of 33 from the UK and North America that examined abundance and population data, found that bird densities, abundances, nesting densities or use of wild bird cover was higher than in other habitats or management regimes, or that sites with wild bird cover had higher populations than those without. These studies included a systematic review and seven randomised, replicated and controlled studies. Some studies found that this was the case across all species or all species studied, while others found that only a subset showed a preference. Four studies investigated other interventions at the same time. Thirteen of the 33 studies (all replicated and from Europe and the USA), found that bird populations or densities were similar on wild bird cover and other habitats, that some species were not associated with wild bird cover or that birds rarely used wild bird cover. Three studies from the UK and Canada, two replicated, found higher productivities for some or all species monitored on wild bird cover, compared to other habitats. Two replicated and controlled studies from Canada and France found no differences in reproductive success between wild bird cover and other habitats for some or all species studied. Three studies from Europe and the USA investigated survival, with two finding higher survival of grey partridge Perdix perdix released on wild bird cover or of artificial nests in some cover crops. The third found that survival of grey partridge was lower on farms with wild bird cover, possibly due to high predation. Five studies from the UK, three replicated, found that some wild bird cover crops were preferred to others. A randomised, replicated and controlled study and a review from the UK found that the landscape surrounding wild bird cover and their configuration within it affected use by birds.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F187https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F187Sun, 10 Jun 2012 13:10:33 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for burrow-nesting seabirds Four studies from across the world found evidence for population increases or new populations being established in petrel species following the provision of nest boxes. In two cases nest boxes were combined with the translocation of chicks or other interventions. Six studies from across the world found high occupancy rates for artificial burrows by seabirds, with three finding that occupancy increased over time, taking years to build up. Three studies from across the world found very low occupancy rates for artificial burrows used by petrel species. Eight studies from across the world found that the productivity of birds using artificial burrows was high, in many cases as high or higher than in natural burrows. One replicated study from the USA and a small study from the Galapagos found low productivity of petrels using artificial burrows.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F481https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F481Thu, 30 Aug 2012 16:21:23 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for songbirds Only three studies out of 66 from across the world found low rates of nest box occupancy, although this may be partially the result of publishing biases. Thrushes, crows, swallows and New World warblers were the target species with low rates of use. Thrushes, crows, finches, swallows, wrens, tits, Old World and tyrant flycatchers, New World blackbirds, sparrows, waxbills, starlings and ovenbirds all used nest boxes. One study from the USA found that wrens used nest boxes more frequently than natural cavities. Five studies from across the world found higher population densities or population growth rates in areas with nest boxes, whilst one study from the USA found higher species richness in areas with nest boxes. One study from Chile found that breeding populations (but not non-breeding populations) were higher for two species when next boxes were provided. Twelve studies from across the world found that productivity of birds in nest boxes was higher or similar to those in natural nests. One study found there were more nesting attempts in areas with more nest boxes, although a study from Canada found no differences in behaviour or productivity between areas with high or low densities of nest boxes. Two studies from Europe found lower predation of some species using nest boxes. However, three studies from the USA found low production in nest boxes, either in absolute terms or relative to natural nests. Thirteen studies from across the world founds that use, productivity or usurpation varied with nest box design, whilst seven found no difference in occupation rates or success with different designs. Similarly, fourteen studies found different occupation or success rates depending on the position or orientation of artificial nest sites. Two studies found no difference in success with different positions.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F498https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F498Tue, 04 Sep 2012 13:52:37 +0100Collected Evidence: Collected Evidence: Provide supplementary foodA replicated, controlled study from Europe found that overall, gardens with supplementary food did not contain more species than those without. However, there was some evidence that gardens with supplementary food in five countries did contain more species than unfed ones, when countries were analysed separately.   For specific interventions see: provide supplementary foodCollected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F521https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F521Sat, 08 Sep 2012 13:18:10 +0100Collected Evidence: Collected Evidence: Provide supplementary food for petrels to increase reproductive successA replicated controlled study in Australia found that Gould’s petrel Pterodroma leucoptera chicks provided with supplementary food had very similar fledging rates to both control and hand-reared birds, but were significantly heavier than other birds.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F522https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F522Sat, 08 Sep 2012 13:22:09 +0100Collected Evidence: Collected Evidence: Provide supplementary food for gannets and boobies to increase reproductive success A small controlled study in Australia found that Australasian gannet Morus serrator chicks were significantly heavier if they were supplied with supplementary food, but only in one of two years. Fledging success of fed nests was also higher, but not significantly so. A randomised replicated and controlled study in the Galapagos Islands found that fed female Nazca boobies Sula granti were more likely to produce two-egg clutches if they were fed, and that second eggs were significantly heavier.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F523https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F523Sat, 08 Sep 2012 13:25:20 +0100Collected Evidence: Collected Evidence: Provide supplementary food for auks to increase reproductive success Two replicated and controlled studies from the UK found that Atlantic puffin Fratercula arctica chicks provided with supplementary food were significantly heavier than control chicks. One study found differences between populations, suggesting some are more food-limited than others. The two UK studies found that fed chicks fledged at the same time as controls, whilst a randomised, replicated and controlled study from Canada found that tufted puffin Fratercula cirrhata chicks supplied with supplementary food fledged later than controls. The Canadian study found that fed chicks had faster growth by some, but not all, metrics.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F524https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F524Sat, 08 Sep 2012 13:32:31 +0100Collected Evidence: Collected Evidence: Provide supplementary food for gulls, terns and skuas to increase reproductive success Four studies of three experiments from Europe and Alaska found that providing supplementary food increased fledging success or chick survival in two gull species, although a study from the UK found that this was only true for one island, with abnormally low breeding success. A second island with higher success was not affected by feeding. Two of the experiments fed parent birds and one fed the chicks directly. One study from the Antarctic found no effect of feeding parent skuas on productivity. One study from Alaska found increased chick growth when parents were fed; one study from the Antarctic found no increase in chick growth.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F525https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F525Sat, 08 Sep 2012 13:37:48 +0100Collected Evidence: Collected Evidence: Provide supplementary food for gamebirds to increase reproductive successA controlled study in Tibet found that Tibetan eared pheasants Crossoptilon harmani that were fed supplementary food laid significantly larger eggs and clutches than control birds. Nesting success and laying dates were not affected.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F527https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F527Sun, 09 Sep 2012 17:34:24 +0100Collected 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 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 for parrots to increase reproductive success Two studies from New Zealand found some evidence that providing supplementary food for kakapos Strigopus habroptilus increased the number of breeding attempts made, whilst a third study found that birds provided with specially-formulated pellets appeared to have larger clutches than those fed on nuts. One study found no evidence that providing food increased the number of nesting attempts.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F536https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F536Sun, 09 Sep 2012 19:43:26 +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 gulls, terns and skuas to increase adult survivalA randomised, replicated and controlled study in the Antarctic found that female south polar skuas Catharacta maccormicki that were fed lost more weight whilst feeding two chicks than unfed birds. There was no difference for birds with single chicks, or male birds.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F548https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F548Sun, 16 Sep 2012 09:21:14 +0100Collected Evidence: Collected Evidence: Provide supplementary food for pigeons to increase adult survival A study of a recently-released pink pigeon Nesoenas mayeri population on Mauritius found that fewer than half the birds used supplementary food, and appeared to survive without it. However, a later study of the population found that almost all birds were recorded using supplementary feeders.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F549https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F549Sun, 16 Sep 2012 09:24:17 +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: Provide supplementary food after release Three studies from found that malleefowl Leipoa ocellata, Andean condors Vultur gryphus and pink pigeons Nesoenas mayeri used supplementary food when it was provided after release. A replicated, controlled study from Australia found that malleefowl had higher survival when supplied with supplementary food. A study in Peru found that supplementary food could be used to increase the foraging range of condors after release, or to guide them back to suitable feeding areas.  Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F639https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F639Sun, 14 Oct 2012 23:54:01 +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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