Conservation Evidence: Evidence Data

Collected 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: Plant grass buffer strips/margins around arable or pasture fields for birds One replicated controlled study from the USA found that there were more species in fields bordered by margins than unbordered fields. Two replicated studies from the UK, one with paired sites, found no effect of field margins on species richness. A replicated, controlled study from the UK found that more birds and more species used sown strips in fields than the fields themselves, but even more used field margins. Nine studies from the UK and USA, seven replicated, two controlled, found more positive population trends, higher populations or strong habitat associations for some or all species for sites with grass margins to fields. One study investigated multiple interventions. Three replicated studies from the UK found that grass field margins did not have a positive effect on populations of some or all bird species investigated. Both studies that examined habitat use (one replicated, both from the UK) found that species used margins more than other habitats. A randomised, replicated and controlled study from the UK found that birds used cut margins more than uncut margins during winter but less than other management regimes during summer. The authors argue that management type is more important than the seed mix used to sow the margins. A replicated study from the UK found that grey partridge Perdix perdix had smaller broods in grass margins than other habitat types. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F191https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F191Wed, 27 Jun 2012 16:39:04 +0100Collected Evidence: Collected Evidence: Leave overwinter stubbles The three studies from the UK (one replicated) that report population-level changes found positive effects of over-winter stubble provision, but all investigated multiple interventions at once. Eight studies from the UK, including a systematic review, found that at least some species or groups of farmland birds were positively associated with over-winter stubbles, or were found on stubbles. Three studies investigated multiple interventions without separating the effects of each. Two studies reported that seed-eating birds in particular were more abundant on stubbles. One of the eight studies found that no more positive responses to stubbles were found than would be expected by chance. A replicated, randomised and controlled study from the UK found that 22 of 23 species did not preferentially use stubbles compared to cover crops. A replicated study from the UK found that the area of stubble in a site was negatively related to grey partridge Perdix perdix brood size. Five studies from the UK, four replicated, found that stubble management affected use by birds. Some species or groups were more common on cut stubbles, some on uncut and some showed preferences for barley over wheat. One study found that only Eurasian skylarks Alauda arvensis were more common on stubbles under agri-environment schemes, and only on highly prescriptive schemes. One study found that all seed-eating species were more abundant on stubbles under agri-environment schemes in one of two regions studied. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F203https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F203Mon, 09 Jul 2012 15:13:01 +0100Collected Evidence: Collected Evidence: Reduce grazing intensity Nine studies from the USA and the UK, one replicated and controlled, found increases in populations of some species on fields with reduced grazing, or increased use of such fields by birds. Three of the studies used multiple interventions at once. Five studies from Europe, four replicated and controlled, found that some or all species were no more numerous on fields with reduced grazing, compared to intensively-grazed fields. One paired sites study from the UK found that black grouse Tetrao tetrix populations increased at reduced grazing sites (and declined elsewhere), but that large areas of reduced grazing had lower densities of female grouse. A before-and-after study from the USA found that the number of species on plots with reduced grazing increased over time. A replicated, controlled study from four countries in Europe found no differences in the number of species on sites with low-intensity or high-intensity grazing. One replicated trial in the UK found that some bird groups preferred grassland short in winter (grazing effect simulated by mowing), and others preferred it long (unmown to simulate removal of livestock). Frequency and timing of the simulated grazing did not alter this preference. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F220https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F220Tue, 17 Jul 2012 13:28:12 +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%2Fconservationevidencejournal.com%2Factions%2F244https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F244Wed, 18 Jul 2012 11:00:04 +0100Collected Evidence: Collected Evidence: Use streamer lines to reduce seabird bycatch on longlines A total of eight studies and two literature reviews from coastal and pelagic fisheries across the world found strong evidence for reduced seabird bycatch on longlines when streamer lines were used. A replicated, controlled trial from the sub-Antarctic Indian Ocean found no reduction in bycatch rates when using streamer lines, whilst five studies were inconclusive, uncontrolled or had weak evidence for reductions. The effect of streamer lines appears to vary between seabird species: northern fulmars Fulmarus glacialis were consistently caught at lower rates when streamers were used but shearwaters Puffinus spp. and white-chinned petrels Procellaria aequinoctialis were caught at similar rates with and without streamers in one study each. The three studies that investigated the use of multiple streamer lines all found that fewer birds were caught when two streamer lines were used, compared to one, with even fewer caught when three were used. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F285https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F285Tue, 24 Jul 2012 14:37:19 +0100Collected Evidence: Collected Evidence: Use prescribed burning on pine forests Two studies of the 28 captured (all from the USA) found higher bird species richness in sites with prescribed burning, tree thinning and mid- or understorey control or just burning and tree thinning, compared to control sites. Five studies found no differences in species richness or community composition between sites with prescribed burning; prescribed burning, tree thinning and mid- or understorey control; or prescribed burning and tree thinning only, compared to control sites, or those with other management. Eight studies found that some species or guilds (such as open habitat species) were more abundant or more likely to be found in burned areas of pine forest than control areas. One study found that the responses of Henslow’s sparrows to burning varied considerably with geography and habitat. Three studies found that some species were more abundant in thinned and burned stands, compared to controls or other management. Three studies found that overall bird densities or abundances of red-cockaded woodpeckers were higher in open pine forests with prescribed burning, tree thinning and mid- or understorey control, compared with control areas or those thinned but not burned. One found differences were more marked in spring. A study found that a red-cockaded woodpecker population increased following the start of intensive management consisting of prescribed burning and other interventions. Ten studies found that total bird densities or those of some species was the same or lower in sites with prescribed burning compared to control sites, or those with other management. Five studies investigated several interventions at once. Generally, closed-forest species and ground nesters appeared to be adversely affected by burning. Three studies found higher productivities or survival of species in burned or burned and thinned areas, compared to control areas or those burned less recently. Seven studies found no differences in productivity, behaviour or survival (including of artificial nests) in burned areas or burned and thinned areas, compared to controls. One study found that northern bobwhite chicks had lower foraging success in burned areas, compared to other management regimes, whilst another found that different predators were dominant under different management. The three studies that investigated it found that burning season did not appear to affect the effects of burning. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F318https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F318Thu, 26 Jul 2012 13:02:39 +0100Collected Evidence: Collected Evidence: Use prescribed burning on grasslands Four studies from the USA, of 21 studies captured, found that overall species richness did not vary between burned areas, or areas burned recently, and unburned sites. One study found that community composition was also similar whilst others found that species showed individual responses. Nine studies from across the world found that at least some study species were found at higher densities or were more abundant in burned areas than in unburned areas or areas under different management. One study investigated multiple interventions at once. Fourteen studies found that at least one study species was less abundant or found at similar abundances on burned areas of grassland, compared to unburned areas or those under different management. However, four studies found that apparent responses varied depending on how soon after fires measurements were taken. Care should therefore be taken when interpreting the results of studies on prescribed burning. One study from the USA found that Florida grasshopper sparrow had significantly higher reproductive success soon after plots were burned, whilst another American study founds that dickcissel reproductive success was higher in patch-burned areas than burned and grazed areas. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F322https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F322Thu, 26 Jul 2012 15:38:18 +0100Collected Evidence: Collected Evidence: Thin trees within forests Of 13 studies, one from the USA which used several interventions found higher species richness in managed sites. Three studies from the USA and the UK found no differences between thinned and control sites. Seven studies from the USA and Sweden found that total bird abundance, or that of some species, were higher in thinned plots than control plots or those under different management. Four of these used other interventions as well. Five studies found that abundances were similar, or that some species were less abundant in areas with thinning. Two studies from the USA found no effect of thinning on wood thrushes, a species thought to be sensitive to it. A controlled before-and-after study found that more nests were in nest boxes in a thinned site, compared to a control site. A replicated randomised, controlled study in the USA found no differences in bird abundances between burned sites with high-retention thinning, compared to low-retention. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F328https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F328Thu, 26 Jul 2012 17:16:33 +0100Collected Evidence: Collected Evidence: Manually control or remove midstorey and ground-level vegetation (including mowing, chaining, cutting etc) in forests Of fifteen studies captured, one, a replicated controlled study from the USA, found higher bird species richness in areas with midstorey thinning, compared to control areas. One study from the USA found similar bird species richness in areas with mid- and understorey control, compared to other management types. A study from Canada found fewer species in treated sites than controls. Seven studies from Europe and the USA found that total bird densities or those of some species or guilds were higher in areas with mid- or understorey management, compared to before management or to areas without management. Four of these studies used understorey removal as part of a wider management regime. Five studies from the USA and Canada found that densities of some species were lower in areas with midi or understorey control, or that overall bird densities did not different between managed and unmanaged areas. Two of these studies investigated several interventions at once. A replicated controlled study from the USA found similar survival for black-chinned hummingbirds in areas with understorey management, compared to areas with other interventions. Two replicated, controlled studies from Canada found higher nest survival in forests with removal of deciduous trees, compared to controls. A controlled study found that northern bobwhite chicks had greater foraging success in areas with cleared understorey vegetation compared to burned areas, but lower than under other managements. A replicated, controlled study from the USA found that midstorey control did not appear to affect competition between species for nesting sites. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F335https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F335Sat, 28 Jul 2012 14:20:23 +0100Collected Evidence: Collected Evidence: Employ grazing in natural grasslands Five of 12 studies from the USA and Canada, four replicated, found that some species studied were found at higher densities on grazed than ungrazed sites. Eight studies from the USA, Canada and France, six replicated, found that some or all species studied were found at lower densities on grazed sites compared to ungrazed sites or those under other management, or that there were no differences. Two controlled studies from the USA and Canada, one replicated, found that duck nesting success was higher on grazed than ungrazed sites. Two studies from the USA found that songbird nesting success was lower on grazed than ungrazed sites. Three replicated and controlled (one randomised) studies from the USA and Canada found that grazing had little or no effect on nesting success in a variety of species. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F348https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F348Sun, 29 Jul 2012 14:35:22 +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%2Fconservationevidencejournal.com%2Factions%2F360https%3A%2F%2Fconservationevidencejournal.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%2Fconservationevidencejournal.com%2Factions%2F361https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F361Tue, 31 Jul 2012 13:44:05 +0100Collected Evidence: Collected Evidence: Control mammalian predators on islands for seabirds We found 16 before-and-after studies, one paired sites study and one literature review from around the world, all describing positive seabird responses to the removal or control of mammalian predators (mainly rats Rattus spp. and feral cats Felis catus) from islands. Of these 18 studies, seven found either large population increases or recolonisations following predator eradication or control. Two of these found only partial population increases or recolonisations: a study from Alaska. Twelve studies found increases in reproductive success and survival or decreases in predation and mortality following predator control. In one case there was also a small population increase. Rats and mice Mus musculus were controlled in twelve studies, mostly examining burrow-nesting seabirds; cats in eight, mostly on ground or cliff-nesting seabirds; and other species in two. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F375https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F375Tue, 07 Aug 2012 15:57:05 +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 wildfowl Six studies from North America and Europe found that wildfowl populations increased with the provision of artificial nests, although one study from Finland found that there was no increase in the number of broods or chicks in areas with nest boxes. Twelve studies from North America investigated the success of nests in artificial nests with nine finding that success and productivity was high, sometimes higher than or similar to natural nests. Two studies found that success for some species in nest boxes was lower than for natural nests. Two studies investigated the impact of nest box location, finding that hidden nests had higher success and that nests over water were more successful than those in trees over land. Nineteen studies from across the world investigated occupancy rates of artificial nests, finding that rates varied from no use of 25 nest boxes in a single site in Indonesia to 100% occupancy across 20 sites in the USA with one study finding that nest boxes were used more than natural cavities. Two studies found that occupancy rates increased over time, whilst four studies found that occupancy rates appeared to be affected by design or positioning. Three studies from North America found that nest boxes could have other impacts on reproduction and behaviour, with common starlings Sturna vulgaris (a nest site competitor) avoiding some nest box designs; hidden nest boxes having lower intra-specific nest parasitism than easily visible boxes and female common eiders Somateria mollissima losing less weight over incubation if they were nesting in shelters, compared to birds nesting in the open, although they lost weight quicker after nesting. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F482https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F482Sat, 01 Sep 2012 14:23:12 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for falcons Four studies from the USA and Europe found that local populations of falcons increased following the installation of artificial nesting sites, with one reporting that there was no decline in natural nest use following the installation and use of nest boxes. A replicated study from Canada found that the local population of American kestrels Falco sparverius did not increase following the erection of nest boxes. Eight studies from across the world found that the success and productivity of falcons in nest boxes was high and equal to, or higher than those in natural nests. Four studies from across the world found that productivities in nest boxes were lower than in natural nests or in previously published results, or that some falcons were evicted from their nests by barn owls Tyto alba. Four studies from across the world found no differences in productivity between nest box designs or positions, whilst two, from Spain and Israel found that productivity in boxes varied between designs and habitats. Twenty-one studies from across the world found nest boxes were used by falcons, with one in the UK finding that nest boxes were not used at all. One study from Canada found that falcons preferentially nested in nest boxes over natural nest sites; a study from Mauritius found that most breeding attempts were in nest boxes Four studies found that use increased over time. Seven studies found that position or design affected use, whilst three found no differences between design or positioning. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F489https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F489Mon, 03 Sep 2012 14:01:21 +0100Collected Evidence: Collected Evidence: Provide artificial nesting sites for owls Three studies from the UK appeared to show increases in local populations of owls following the installation of artificial nests, although the authors from one note that they could not rule out birds merely switching from natural nest sites. Another UK study found that providing nesting sites when renovating buildings maintained barn owl Tyto alba populations, whilst they declined at sites without nests. Four studies from the USA and the UK found high levels of breeding success in artificial nests, three finding equal or higher productivity than natural nests. A replicated, controlled study from the USA found lower productivity from artificial nests, whilst a replicated, controlled study from Finland found that artificial nests were only successful in the absence of larger owls and a replicated, controlled study from Hungary found that fledglings from artificial nests were less likely to be found alive after one year. Four studies from the USA and Europe found that artificial nests were used at least as frequently as natural nesting sites. Five studies from across the world found that owls used artificial nests, with one finding that use increased over time, although only for one of two species. Three studies found that owls differentiated between nests in different positions, whilst five studies found that different designs of nests differed in occupancy or productivity. Three studies found occupancy did not differ between designs and two found no differences in productivity for different designs. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F490https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F490Mon, 03 Sep 2012 15:06:04 +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 food for songbirds to increase reproductive success Two studies from the USA found evidence for higher population densities of magpies and American blackbirds in areas provided with supplementary food, whilst two studies from the UK and Canada found that population densities did not appear to be affected by feeding. Twelve studies from across the world found that breeding productivity was higher for fed birds than controls. The increases were through higher hatching or fledging rates, or higher chick survival or recruitment rates. One study from the USA found that these increases were only found in dry years. Eleven studies from Europe and the USA found that fed birds had no higher, or even lower breeding productivity or chick survival than control birds. Nine studies from Europe and North America found that the eggs of fed birds were larger or heavier, or that the chicks of fed birds were in better physical condition: being larger, heavier, faster growing, more symmetrical or having a better immune response. In one study this was only true in a heavily polluted site. However, eight studies from across the world found no evidence for better condition or increased size in the eggs or chicks of fed birds. Six studies from across the world found that food-supplemented pairs laid larger clutches than unfed birds, whilst 14 studies from Europe and North America found that fed birds did not lay larger clutches, or even laid smaller ones. Fifteen studies from across the world found that birds supplied with supplementary food began nesting or laying earlier than controls, although in two studies this was only true for young females or in one of two habitats. In one study, a high fat, high protein diet had a greater effect on laying date than a high fat, low protein diet. One study found that fed birds had shorter incubations than controls whilst another found that fed birds re-nested quicker than controls and had shorter second incubations. Four studies from the USA and Europe found that fed birds did not lay any earlier than controls. Seven studies from across the world found that fed parent birds showed positive behavioural responses to feeding, such as being more likely to re-nest, less likely to be parasitized or showing better anti-predator responses, spending more time incubating or building larger nests. Three studies from across the world found neutral or negative responses to feeding, including being more likely to be invaded by conspecifics, making no more breeding attempts or showing no preference for fed nest boxes compared to controls. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F537https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F537Sun, 09 Sep 2012 19:58:27 +0100Collected Evidence: Collected Evidence: Provide supplementary food for songbirds to increase adult survival Seven studies from Europe and the USA found higher densities or larger populations in various songbird species in areas close to supplementary food. Six studies from Europe, Canada and Japan found that population trends or densities in some species were no different between fed and unfed areas. The American study found that populations appeared to follow food, with populations increasing after feeders were erected and decreasing after they were removed. Four studies from Canada, Europe, Japan and the USA found that birds had higher survival when supplied with supplementary food. However, in two studies this was only apparent in females or in one of two species studied. A controlled study in the USA found no evidence that birds were dependent on supplementary food: when food was removed, previously fed birds did not have lower survival than controls. A replicated, controlled study from the USA found that song sparrows Melospiza melodia had lower survival with feeding stations in their territories. Six studies from Europe and the USA found that birds supplied with supplementary food were in better physical condition or had larger fat supplies than unfed birds. However, in one replicated, controlled study this was only the case for females; in another two, only one of three species showed better condition, with one species in one study showing lower condition when fed; a final replicated and controlled study found that differences between treatments were only apparent in the breeding season. Two studies investigated the effect of feeding on behaviours: a randomised, replicated and controlled study in the USA found that male Carolina wrens Thryothorus ludovicianus spent more time singing when supplied with food; a replicated, controlled study in Sweden found no behavioural differences between wood nuthatches Sitta europaea supplied with food, and unfed birds. Thirteen studies from the UK, Canada and the USA investigated use of feeders. Four studies from the USA and the UK found high use of supplementary food by several species, with up to 21% of birds’ daily energy needs coming from feeders. However, another UK study found very low use of food, possibly because the feeder was not positioned close to natural food sources. One UK study found that use of feeders peaked in midwinter, although another found that the exact timing of peak use varied between species. Two replicated trials from the UK finding that the use of feeders increased with distance to houses and decreased with distance to cover, whilst a replicated Candadian study found that American goldfinches Carduelis tristis preferred using bird feeders in high positions. A large-scale replicated study in the UK found that preferences for feeder locations varied between species. Three studies from the UK argue that placing feeders over 1 km apart, and possibly 1.1–1.3 km apart will maximise their use whilst keeping the intervention practical. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F552https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F552Sat, 22 Sep 2012 17:27:20 +0100Collected Evidence: Collected Evidence: Provide calcium supplements to increase survival or reproductive success Eight studies from across the world, including a literature review from across the world found evidence for positive effects of calcium supplementation on several bird species. Positive effects included lower incidence of bone disease, higher fledging succes, larger broods, higher quality eggs or chicks and better physical condition of female parents. Not all species reacted similarly. Six studies including a literature review did not find any evidence for increased reproductive success in at least one of the species supplied with supplementary calcium. One replicated study from Europe found that birds took calcium supplied, and birds at polluted sites took more than those at cleaner sites. The effects on fitness were not monitored. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F559https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F559Sun, 23 Sep 2012 15:19:49 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of raptors Five studies of three release programmes from across the world found the establishment or increase of wild populations of falcons Falco spp. Five studies from the USA found high survival of released raptors (with between one and 204 birds released), whilst two found that released birds behaved normally and hunted successfully. One study from Australia found that a wedge-tailed eagle Aquila audax had to be taken back into captivity after acting aggressively towards humans, whilst another Australian study found that only one of 15 brown goshawks Accipiter fasciatus released was recovered, although the authors do not draw conclusions about survival rates from this. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F626https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F626Sun, 14 Oct 2012 14:54:39 +0100