Providing evidence to improve practice

The journal, Conservation Evidence

Our online journal publishes research, monitoring results and case studies on the effects of conservation interventions. All papers include some monitoring of the effects of the intervention and are written by, or in partnership with, those who did the conservation work. It includes interventions such as habitat creation, habitat restoration, translocations, reintroductions, invasive species control, and education or integrated conservation development programmes, from anywhere around the world.

A volume is created each year with peer-reviewed papers published throughout the year. We now accept Short Communications as well as standard papers.

Special issues contain new papers on a specific topic.

Virtual collections collate papers published in the journal on specific topics such as management of particular groups of species.

To search for papers on a specific topic within the journal select 'Advanced search' on the Home page, enter your keyword(s) and within the Source box type: "conservation evidence".

Bird Reintroductions



To mark the publication of Bird Conservation: Evidence for the Effects of Interventions, we created two new virtual collections.This one contains papers on bird reintroductions, while the other has a selection of papers on bird management.

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In 2015 seven captive-bred red-and-green macaws Ara chloropterus were experimentally released into the Iberá National Park, Corrientes, Argentina. After a month in a pre-release cage, they were hard released. Two birds were preyed upon, three flew beyond our detection range, one transmitter was recovered underwater, and one bird was recaptured. We identify ways in which future releases of captive-bred macaws could be improved.

Attempted re-establishment of a sooty tern Onychoprion fuscatus breeding colony on Denis Island, Seychelles
Feare C.J., French G.C.A., Nevill J.E.G., Pattison-Willits V.S., Wheeler V., Yates T.L., Hoareau C. & Prescott C.V. (2015), 12, 19-24

Seychelles supports around three million nesting pairs of sooty terns. However, there have been recent declines and the colonies continue to face ongoing threats from habitat change and excessive commercial harvesting of their eggs, as well as potential threats by commercial fishing and climate change. A possible method to counter these threats is to re-establish breeding colonies on islands from which they have disappeared. An attempt was made to attract birds to a previously occupied island through habitat management, decoy birds and playback of recorded sooty tern calls. Habitat preparation involved predator eradication and tree removal to provide open ground with bare sandy areas and low herb vegetation. Overflying birds were attracted by broadcast calls, with some circling over and landing among the decoys. Large three-dimensional plastic models were superior to other models presented. This study demonstrated that large numbers of birds can be attracted by these means and that the birds then undertook behaviour associated with breeding, including egg laying by a few birds. However, after five seasons a breeding colony has not yet been established; one possible cause is the emergence of unexpected egg predators, common moorhen Gallinula chloropus and common myna Acridotheres tristis.

Fifty-three captive-bred, sub-adult red-billed curassow Crax blumenbachii were reintroduced to the Guapiaçu Ecological Reserve, Brazil, from 2006 to 2008.  Post-reintroduction movements were monitored for 25 months, but little information on breeding was collected during this period as few of the birds had reached sexual maturity. However, in the period 2009-2014, six observations of probable breeding were made. This positive outcome will help inform the feasibility of further reintroductions.

In December 2011, 59 adult Seychelles warblers Acrocephalus sechellensis were translocated between two islands in the Seychelles. Birds were captured on Cousin Island and translocated to Frégate Island using a hard release method, with minimum time in captivity. Frégate had been previously identified as a suitable host for a substantial population of Seychelles warblers, although the presence of the species had never been confirmed on this island. It was estimated that Frégate currently has the potential to support about 500 Seychelles warblers, rising to over 2,000 after habitat regeneration. All birds survived the translocation and were released unharmed at the new site within 24 hours of capture. Close monitoring of both the new and source population was undertaken over a period of 18 months. By June 2013, the Frégate population had increased to 80 individuals, which included 38 of the original translocated birds and 42 birds which had hatched on Frégate. There was also evidence that multiple generations had already hatched on the island. This shows that the Seychelles warbler responded well to a hard release translocation, with observed population growth on Frégate comparable to previous warbler translocations. The source population on Cousin recovered to carrying capacity within a single breeding season. This is the fourth translocation of this species, fulfilling the species action plan requirement of five populations of this endemic island passerine.

The global range of the Aldabra white-throated rail Dryolimnas cuvieri aldabranus, the last surviving flightless bird in the Indian Ocean, was restricted to only three islands of Aldabra Atoll in 1998. It was extirpated on the islands of Grand Terre (before the late 1800s) and Picard (soon after 1910), mainly due to the introduction of feral cats by early settlers. In 1999, following the eradication of cats from Picard, 18 Aldabra rails were successfully reintroduced. After the reintroduction, population growth of the Aldabra rail on Picard was predicted to continue to approximately 1,000 pairs by 2010. In this paper, we report on the long-term effectiveness of the reintroduction by updating the Aldabra rail population estimate on Picard 12 years after the translocation and one year after the predicted maximum was expected to be reached. We confirm the predicted carrying capacity on Picard has been reached and probably exceeded; report a reliable survey method for the Aldabra rail, which can be applied to other terrestrial bird species; and recommend subsequent monitoring and conservation management strategies for the Aldabra rail and potentially other species of rail.

 

In March 2009, 79 hihi (stitchbird) Notiomystis cincta were translocated from Tiritiri Matangi and Little Barrier (Hauturu) Islands to Maungatautari, a 3,255 ha New Zealand mainland reserve with a predator (exotic mammals) exclusion fence. Genetic management, by mixing founders from both a reintroduced and highly productive site (Tiritiri Matangi) and the only naturally occurring extant population (Little Barrier), appears successful with at least one mixed pairing producing fledglings in the first breeding season after release. Monitoring this population is challenging due to the large area and rugged terrain of the reserve.  However, closed mark-recapture analysis based on a 15-day survey about 1 year after release indicated that between 15 and 41 (19 - 52%) of the translocated hihi had survived.  Unringed hihi were also observed during this survey (25 observations but it is unknown how many of these were the same individuals), indicating successful breeding in the first year. If they persist and thrive in the longer term, this translocation will provide an important hihi population at a large mainland site and will contribute to the ongoing ecological restoration of Maungatautari.

The red-fronted parakeet Cyanoramphus novaezelandiae is a vulnerable New Zealand endemic with a fragmented distribution, mostly inhabiting offshore islands free of introduced mammalian predators. Four populations have been established since the 1970s using captive-bred or wild-sourced individuals translocated to islands undergoing ecological restoration. To establish a new population in the Hauraki Gulf, North Island, a total of 31 parakeets were transferred from Little Barrier Island (Hauturu) to Motuihe Island in May 2008 and a further 18 in March 2009. Overall 55% and 42% of individuals from the first translocation were confirmed alive at 30 and 60 days post-release, respectively. Evidence of nesting and unassisted dispersal to a neighbouring island was observed within a year of release. These are outcomes are promising and indicate that translocation from a remnant wild population to an island free of introduced predators is a useful conservation tool to expand the geographic range of red-fronted parakeets.

 

A translocation of South Island saddlebacks Philesturnus carunculatus from Ulva Island to Orokonui Ecosanctuary near Dunedin, New Zealand was conducted by a community group and university scientists in April 2009. In this paper we describe and assess methods used during this complicated five day translocation, which involved birds being held over-night in transfer boxes. Post-release surveys determined a minimum of 79% of individuals survived the critical initial 48 h after release. The survival rate did not appear to be affected by the presence or absence of perches in each transfer box, although the lack of perches does not follow best-practice for most passerine translocations. Experienced advisors should be involved during every phase of the translocation process.

 

The release and establishment of Mauritius fodies Foudia rubra on Ile aux Aigrettes, Mauritius
Cristinacce A., Handschuh M., Switzer R.A., Cole R.E., Tatayah R.V.V. & Jones C.G. (2009), 6, 1-5

The Mauritius fody Foudia rubra is threatened by habitat loss and nest predation from introduced mammalian predators. The establishment of populations on predator-free smaller islands around 'mainland' Mauritius is one of the main conservation strategies for endangered Mauritian birds. Ninety-three Mauritius fodies were released on Ile aux Aigrettes in three breeding seasons between November 2003 and March 2006. The first fledglings were produced on the island during the 2004-05 breeding season, and by the following season sufficient numbers of juveniles were being produced on the island to render further releases unnecessary. The population has since increased to 47 breeding pairs and 142 individuals as of December 2008.

The Kermadec red-crowned parakeet Cyanoramphus novaezelandiae was driven to extinction on Raoul Island over 150 years ago by introduced cats Felis catus and rats (Rattus norvegicus and R.exulans). These predators were eradicated from the island (2,938 ha) between 2002-04 during the world's largest multi-species eradication project. In 2008 we documented a unique recolonisation event when parakeets were observed to have returned to Raoul, presumably from a nearby island group, The Herald Islets (51 ha). We captured and aged 100 parakeets, of which 44% were born in 2008, and breeding was observed on Raoul Island. This represents the first evidence of nesting of this species on Raoul Island since 1836. Our findings highlight the global conservation potential for island avifaunas by prioritising eradication areas through consideration of proximity of remnant populations to target management locations, instead of the classical translocation approach alone. The natural recolonization of parakeets on Raoul Island from a satellite source population is to our knowledge, a first for parrot conservation and the first documented population expansion and island recolonization of a parrot species after removal of invasive predators.

We report on the translocation of Seychelles magpie-robins Copsychus sechellarum, from the island of Frégate to the island of Cousin between 1994 and 1995. Prior to this translocation, the world population consisted of 47 individuals confined to Frégate . Five magpie-robins were translocated to Cousin and subsequently a new self-sustaining breeding population was established; this population increased almost 10-fold in less than 12 years to a high of 46 individuals in May 2006. It is now currently experiencing signs of regulation with a slight decrease in numbers with 31 birds recorded in June 2007. It is hoped that ongoing studies will identify the reasons for this decline, which at present are unclear.

 

In August 2005, 20 North Island saddleback Philesturnus rufusater were translocated from Tiritiri Matangi Island to Motuihe Island in the Hauraki Gulf, New Zealand. Post release survival over the first year was high (70%). A minimum of 11 juveniles successfully fledged in the 2005/2006 breeding season bringing the population to a minimum of 25 birds one year after release. Assuming long term success this translocation brings the total number of island populations of North Island saddleback to 13 and contributes to the ongoing ecological restoration of Motuihe Island.

In May-June 2004, 58 adult Seychelles warblers Acrocephalus sechellensis were translocated to Denis Island. The first pairs started nest-building within three days of release. By August 2005, their numbers had increased to 75. Of the 35 breeding territory vacancies created by the translocation on the source island of Cousin, all but three were occupied within an average of 5.4 days, by sub-ordinate birds.

A total of 105 (44 wild, 61 captive-bred) Campbell Island teal Anas nesiotis were transferred to Campbell Island in 2004 and 2005. They were kept in pens and released once above normal weight. At least 78% of the 2004 cohort survived five months after release and a minimum of 41 out of 55 survived a similar period in 2005. Successful breeding was proven when two nests and four immature teal were found in 2006.

To restore brown teal Anas chlorotis populations, a captive breeding and release programme has been developed. At the Moehau Kiwi Sanctuary, a first release of 60 teal had a survival rate of 45%, and the second release of 40 birds an 85% survival rate. As the survival rate of the second release was so high, the same methods will be used in the next planned release, in combination with ongoing predator control.