Collected Evidence: Collected Evidence: Clean nest boxes to increase occupancy or reproductive success Five studies from Spain and North America found that various songbirds preferentially nested in cleaned nest boxes, compared to used ones. One study from the USA found that eastern bluebirds showed this preference, but most did not switch from a soiled to a cleaned nest box. One study from the USA found that birds showed an avoidance of heavily-soiled boxes and one from Canada found that tree swallows Tachycineta bicolor preferentially selected nests which were sterilised by microwaving. Two studies from the USA found that eastern bluebirds Sialia sialis and house wrens Troglodytes aedon preferentially nested in uncleaned nest boxes, and one study found that prothonotary warblers Protonotaria citrea showed no preference for cleaned or uncleaned boxes. None of the five studies that investigated it found any difference in success or parasitism levels between cleaned and uncleaned nest boxes.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F499https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F499Tue, 04 Sep 2012 16:10:03 +0100Collected Evidence: Collected Evidence: Use differently-coloured artificial nestsA replicated study from the USA found that two species showed different colour preferences for nest boxes, but that in each case, the preferred colour had lower nesting success than the less preferred colour.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F500https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F500Tue, 04 Sep 2012 16:21:30 +0100Collected Evidence: Collected Evidence: Provide nesting material for wild birds A replicated study in the UK found that songbirds used feathers provided at a very low rate and nest construction did not appear to be resource limited. A replicated, controlled study from Australia found that four species of egrets used supplementary nesting material provided, preferentially taking material from raised platforms over water compared to plots on dry land.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F501https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F501Tue, 04 Sep 2012 16:23:14 +0100Collected Evidence: Collected Evidence: Repair/support nests to support breedingA small study from Puerto Rico found that nine Puerto Rican parrot Amazona vittata nests were repaired, resulting in no chicks dying of cold.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F502https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F502Tue, 04 Sep 2012 16:31:27 +0100Collected Evidence: Collected Evidence: Artificially incubate eggs or warm nests A replicated, controlled trial in the UK found that great tits Parus major were less likely to interrupt their laying sequence if their nest box was heated, although there was no effect on egg or clutch size. A small study in New Zealand found that no kakapo Strigopus habroptilus eggs or chicks died from chilling following the use of nest warmers. Before this a nest had been lost to chilling.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F503https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F503Tue, 04 Sep 2012 16:34:31 +0100Collected Evidence: Collected Evidence: Provide nesting habitat for birds that is safe from extreme weather A small from New Zealand found Chatham Island oystercatchers Haematopus chathamensis used raised nest platforms made from car tyres (designed to raise nests above the level of storm surges). The success of these nests is not reported. Two replicated, controlled studies from the USA found that the nesting success of terns and waders was no higher on specially raised areas of nesting substrate, compared to unraised areas, with one study finding that a similar proportion of nests were lost to flooding in raised and unraised areas.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F504https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F504Thu, 06 Sep 2012 13:55:55 +0100Collected Evidence: Collected Evidence: Remove vegetation to create nesting areas Two out of six studies found that the number of waders and terns nesting in an area increased following the removal of vegetation, and another found that a tern colony moved to an area prepared by removing vegetation. Two of these studies used multiple interventions at once. One study found a decrease in colony size after several interventions, including vegetation control. A study from the UK found that gulls and terns nested in an area cleared of vegetation and a controlled study from Puerto Rico found that although no terns nested in plots cleared completely of vegetation, more nested in partially-cleared plots than in uncleared plots. A before-and-after study from Canada found that tern nesting success was higher after plots were cleared of vegetation and other interventions were used.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F505https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F505Thu, 06 Sep 2012 14:00:49 +0100Collected Evidence: Collected Evidence: Guard nests to increase nest success A before-and-after study from Costa Rica found an increase in scarlet macaw Ara macau population following the monitoring of nests, along with several other interventions. Two studies from Puerto Rico and New Zealand found that parrot nest success was higher or mortality reduced or nest success higher with intensive monitoring of nests, ompared to periods without monitoring. A study from New Zealand also found high overall nest success when nests were monitored.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F506https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F506Thu, 06 Sep 2012 14:12:26 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of gannets and boobies with wild conspecificsA small controlled study in Australia found that Australasian gannet chicks Morus serrator were lighter, and hatching and fledging success lower in nests which had an additional egg or chick added. However, overall productivity was (non-significantly) higher in experimental nests.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F507https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F507Thu, 06 Sep 2012 14:17:32 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of waders with wild conspecifics Two small trials in North America found that piping plovers Charadrius melodus accepted chicks introduced into their broods, although in one case the chick died later the same day. A replicated study from New Zealand found that survival of fostered black stilts Himantopus novasezelandiae was higher for birds fostered to conspecifics rather than a closely related species.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F508https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F508Thu, 06 Sep 2012 14:30:39 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of vultures with wild conspecificsTwo small studies, one a New World vulture and one of an Old World species found that single chicks were successfully adopted by foster conspecifics, although in one case this led to the death of one of the foster parents’ chicks.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F509https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F509Thu, 06 Sep 2012 14:34:30 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of raptors with wild conspecifics Ten out of 11 studies from across the world found that fostering raptor chicks to wild conspecifics had high success rates. A single study from the USA found that only one of six eggs fostered to wild bald eagle Haliaeetus leucocephalus nests were hatched and raised. The authors suggest that the other eggs may have been infertile. A replicated study from Spain found that Spanish imperial eagle Aquila adalberti chicks were no more likely to survive to fledging if they were transferred to foster nests from three chick broods (at high risk from siblicide), compared to chicks left in three-chick broods. A replicated study from Spain found that young (15–20 years old) Montagu's harrier Circus pygargus chicks were successfully adopted, but three older (27–29 day old) chicks were rejected.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F510https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F510Thu, 06 Sep 2012 14:42:31 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of owls with wild conspecifics A replicated study in the USA found high fledging rates for barn owl Tyto alba chicks fostered to wild pairs. A replicated controlled study from Canada found that captive-reared burrowing owl Athene cunicularia chicks fostered to wild nests did not have significantly lower survival or growth rates than wild chicks.    Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F511https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F511Thu, 06 Sep 2012 15:57:35 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of cranes with wild conspecificsA small study in Canada found high rates of fledging for whooping crane Grus americana eggs fostered to first time breeders (which normally have very low fertility).  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F512https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F512Thu, 06 Sep 2012 16:13:08 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of bustards with wild conspecificsA small study in Saudi Arabia found that a captive-bred egg was successfully fostered to a female in the wild.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F513https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F513Thu, 06 Sep 2012 16:18:42 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of woodpeckers with wild conspecifics Three studies from the USA found that red-cockaded woodpecker Picoides borealis chicks fostered to conspecifics had high fledging rates. One small study found that fostered chicks survived better than chicks translocated with their parents.    Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F514https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F514Thu, 06 Sep 2012 16:29:20 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of parrots with wild conspecifics A replicated study from Venezuela found that yellow-shouldered Amazon Amazona barbadensis chicks had high fledging rates when fostered to conspecific nests in the wild. A second replicated study from Venezuela found significantly lower poaching rates of yellow-shouldered Amazons Amazona barbadensis when chicks were moved to foster nests closer to a field base.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F515https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F515Thu, 06 Sep 2012 16:34:58 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of petrels and shearwaters with wild non-conspecifics (cross-fostering)A replicated and partially controlled study from Hawaii found that Newell’s shearwater Puffinus newelli eggs fostered to wedge-tailed shearwater P. pacificus nests had high fledging rates.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F516https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F516Thu, 06 Sep 2012 16:54:21 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of waders with wild non-conspecifics (cross-fostering) A replicated and controlled study from the USA found that killdeer Charadrius vociferus eggs incubated and raised by spotted sandpipers Actitis macularia had similar fledging rates to parent-reared birds. A replicated and controlled study from New Zealand found that cross-fostering black stilt Himantopus novasezelandiae chicks to black-winged stilt H. himantopus nests significantly increased nest success, but that cross-fostered chicks had lower success than chicks fostered to conspecifics’ nests.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F517https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F517Thu, 06 Sep 2012 17:03:55 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of ibises with wild non-conspecifics (cross-fostering)A 2007 literature review describes attempting to foster northern bald ibis Geronticus eremite chicks with cattle egrets Bubulcus ibis as unsuccessful.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F518https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F518Thu, 06 Sep 2012 17:07:49 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of cranes with wild non-conspecifics (cross-fostering)Two studies from the USA found low fledging success for cranes fostered to non-conspecifics’ nests.    Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F519https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F519Thu, 06 Sep 2012 17:13:19 +0100Collected Evidence: Collected Evidence: Foster eggs or chicks of songbirds with wild non-conspecifics (cross-fostering) A replicated study from the USA found that the survival of cross-fostered yellow warbler Dendroica petechia chicks was lower than previously-published rates for the species, although incubation and nestling periods were very similar. A replicated and controlled study from Norway found that the success of cross-fostering small songbirds varied depending on the species of chick and foster birds. However, only great tits P. major raised by blue tits P. caeruleus had lower pairing success than control birds, whilst blue tits raised by coal tits P. ater had higher recruitment than controls, or those raised by great tits.  Collected Evidencehttps%3A%2F%2Fwww.conservationevidence.com%2Factions%2F520https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F520Thu, 06 Sep 2012 17:37:20 +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%2Fwww.conservationevidence.com%2Factions%2F521https%3A%2F%2Fwww.conservationevidence.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%2Fwww.conservationevidence.com%2Factions%2F522https%3A%2F%2Fwww.conservationevidence.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%2Fwww.conservationevidence.com%2Factions%2F523https%3A%2F%2Fwww.conservationevidence.com%2Factions%2F523Sat, 08 Sep 2012 13:25:20 +0100
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What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

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