Conservation Evidence: Evidence Data

Collected 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 gamebirds One of five studies from across the world found that releasing gamebirds established a population or bolstered an existing population, although the authors argued that the population of 30–40 western capercaillie Tetrao urogallus (from nearly 400 released) was unlikely to be self-sustaining. A review of a reintroduction programme in Pakistan found some breeding success in released cheer pheasants Catreus wallichii, but that habitat change at the release site then excluded released birds. Three studies from Europe and the USA found that released birds had low survival, low reproductive success and had no impact on the wild population. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F619https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F619Sun, 14 Oct 2012 13:38:41 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of rails One replicated study from Australia found that released Lord Howe Island woodhens Tricholimnas sylvestris successfully bred in the wild, re-establishing a wild population. A replicated study from the UK found high survival of released corncrake Crex crex in the first summer (although no data were available on overwinter survival or breeding). A replicated study in New Zealand found very low survival of North Island weka Gallirallus australis greyi following release, mainly due to predation by invasive mammals. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F620https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F620Sun, 14 Oct 2012 13:58:52 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of cranes Four studies of five release programmes from the USA and Russia, from a total of eight programmes, found that released cranes had high survival or bred in the wild. Two studies from two release programmes in the USA found low survival of captive-bred eggs fostered to wild birds, compared with wild eggs, or a failure to increase the wild flock size. A worldwide review found that releases of migratory species only tended to be successful if birds were released into existing flocks, with higher success for non-migratory populations. One study from the USA found that birds released as sub-adults had higher survival than birds cross-fostered to wild birds. One study from the USA found that 73% of all mortalities occurred in the first year after release. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F621https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F621Sun, 14 Oct 2012 14:04:41 +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%2Fconservationevidencejournal.com%2Factions%2F622https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F622Sun, 14 Oct 2012 14:23:17 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of wadersA review of black stilt Himantopus novaezelandiae releases in New Zealand found that birds had low survival (13–20%) and many moved away from their release sites so, in consequence, that they could not be managed and were unlikely to interact with stilt populations in the wild. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F623https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F623Sun, 14 Oct 2012 14:32:46 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of storks and ibisesA replicated study and a review of northern bald ibis Geronticus eremita release programmes in Europe and the Middle East found that only one of four had resulted in a wild population being established or supported, with many birds dying or dispersing, rather than forming stable colonies. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F624https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F624Sun, 14 Oct 2012 14:38:18 +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 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 +0100Collected Evidence: Collected Evidence: Release captive-bred individuals into the wild to restore or augment wild populations of owls A study in the USA found that a barn owl Tyto alba population was established following the release of 157 birds in the area over three years. A replicated, controlled study in Canada found that released burrowing owls Athene cunicularia had similar reproductive output, but higher mortality than wild birds, and no released birds returned after migration, although return rates for released birds’ offspring were no different from wild birds. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F627https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F627Sun, 14 Oct 2012 22:47:34 +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 parrots A before-and-after study from Venezuela found that the local population of yellow-shouldered amazons Amazona barbadensis increased significantly following the release of captive-bred birds, along with other interventions. A replicated study in Costa Rica and Peru found high survival and some breeding of scarlet macaw Ara macao after release. Three replicated studies in the USA, Dominican Republic and Puerto Rico found low survival in released birds (4–41% in the first year after release), although the Puerto Rican study also found that released birds bred successfully. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F629https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F629Sun, 14 Oct 2012 22:56:19 +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: Use appropriate populations to source released populations A replicated study from Sweden and a small study from France found that birds sourced from populations distant from where they were released were less successful than birds from the area. In Sweden, released white storks Ciconia ciconia from North Africa produced fewer than half the chicks as those that naturally re-colonised, whilst both studies found that storks and little bustards Tetrax tetrax were less likely to migrate than birds originating in the release area. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F631https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F631Sun, 14 Oct 2012 23:16:17 +0100Collected Evidence: Collected Evidence: Use holding pens at release sites Three replicated and one small study from three release programmes in Saudi Arabia, the USA and Canada found that released birds had higher survival or were more likely to pair up if kept at release sites in holding pens before release. A replicated study in the USA found lower survival for thick-billed parrots Rhynchopsitta pachyrhyncha released in holding pens, compared to birds released without preparation. A review of northern bald ibis Geronticus eremita conservation found that holding pens successfully prevented most birds from migrating (which resulted in 100% mortality), although some 200 birds ‘escaped’ over 25 years. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F632https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F632Sun, 14 Oct 2012 23:22:45 +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%2Fconservationevidencejournal.com%2Factions%2F633https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F633Sun, 14 Oct 2012 23:29:34 +0100Collected Evidence: Collected Evidence: Release birds in groupsA replicated study from New Zealand found that released black stilts Himantopus novaezelandiae were more likely to move long distances after release if they were released in larger groups. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F634https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F634Sun, 14 Oct 2012 23:34:47 +0100Collected Evidence: Collected Evidence: Release birds in ‘coveys’ A replicated study in Saudi Arabia found that houbara bustard Chlamydotis undulata macqueenii survival was low when chicks were released in coveys with flightless females. A review of cackling goose Branta hutchinsii conservation and a replicated study in England found that geese and grey partridge Perdix perdix releases were more successful for birds released in coveys than for young birds released on their own or adults released in pairs. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F635https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F635Sun, 14 Oct 2012 23:35:50 +0100Collected Evidence: Collected Evidence: Release birds as adults or sub-adults, not juveniles Three replicated studies found that malleefowl Leipoa ocellata, houbara bustards Chlamydotis undulata macqueenii and cackling geese Branta hutchinsii released as sub-adults, not juveniles had higher survival rates. A replicated study from New Zealand found lower survival for black stilts Himantopus novaezelandiae released as sub-adults, compared with juveniles. Two replicated studies from Hawaii and Saudi Arabia found lower survival for Hawaiian geese Branta sandvicensis and bustards released as wing-clipped sub-adults, compared with birds released as juveniles. Three replicated studies found no differences in survival between ducks, vultures and ibises released at different ages, but a second study of the vulture release programme found that birds released when more than three years old had lower reproductive success than birds released at an earlier stage. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F636https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F636Sun, 14 Oct 2012 23:39:47 +0100Collected Evidence: Collected Evidence: Use ‘anti-predator training’ to improve survival after release A review from Pakistan and a small trial from Saudi Arabia found that pheasants and bustards had higher survival after release, when given pre-release predator training, compared to birds without training, many of which were predated. The Saudi Arabian study found that introducing a model fox (as opposed to a live predator) to cages did not increase post-release survival. Introducing a live fox to the cage increased post-release survival more than other techniques used. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F637https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F637Sun, 14 Oct 2012 23:49:41 +0100Collected Evidence: Collected Evidence: Use ‘flying training’ before releaseA replicated study from the Dominican Republic found that captive-reared Hispaniolan parrots Amazona ventralis had higher initial survival if they were given pre-release predator training, although this difference was not present a year after release.Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F638https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F638Sun, 14 Oct 2012 23:51:20 +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 +0100Collected Evidence: Collected Evidence: Use microlites to help birds migrateA review of northern bald ibis Geronticus eremita conservation found that a group of birds followed a microlite from Austria to Italy but none made the return journey. Collected Evidencehttps%3A%2F%2Fconservationevidencejournal.com%2Factions%2F640https%3A%2F%2Fconservationevidencejournal.com%2Factions%2F640Sun, 14 Oct 2012 23:58:53 +0100