Hugh Wright

Identifying Nest Predators to Guide the Conservation of Critically Endangered White-Shouldered Ibis

White-shouldered Ibis at a seasonal pool.

Camera installation being undertaken at night, thereby minimising the chance of nest abandonment or installation-induced crow predation.

White-shouldered Ibis chicks.

Chicks getting fed.

Town/RegionCountryCategoriesDate
Western Siem Pang IBA, Stung Treng ProvinceCambodiaAsia, Birds17 Feb 2010

The critically endangered White-shouldered Ibis, Pseudibis davisoni, has been hailed as the most threatened large waterbird in South-East Asia. The species declined dramatically between the 1920s and 1960s, disappearing from the majority of its former range. It is now confined almost entirely to northern and eastern Cambodia. Much of the species’s basic ecology and the reasons for the decline are poorly understood. Since 2008, University of East Anglia, UK, has been conducting research on this species in collaboration with conservation partners in Cambodia.

White-shouldered Ibis breed during the dry season (December-May), when they take advantage of amphibian and invertebrate prey at seasonal pools, found frequently in the dry dipterocarp forest landscapes. They are solitary breeders, nesting in tall dipterocarp trees and typically laying 3 eggs. The largest known breeding population occurs at Western Siem Pang IBA in Stung Treng province, where 13 nests were located in the 2008-2009 season. A study of nest productivity at this site found that nest success was low, with a 65% failure rate during the incubation and brooding stages.

Predation is the likely cause of these nest failures but the predators responsible are unconfirmed. Possibilities include Common Palm Civet (Paradoxurus hermaphrodites), Yellow-throated Marten (Martes flavigula) and Southern Jungle Crow (Corvus macrorhynchos). This project is using specially-built nest cameras from the Royal Society for the Protection for Birds to photograph predators when they enter the nest. Cameras will be installed at several nests in 2010-2011, while taking necessary precautions to prevent unwanted disturbance to the ibis.

Predator events captured as these nests will provide the first evidence of predator species and their relative importance. This information will inform conservationists of the best techniques for nest protection. For example, if mammalian and/or reptilian predation proves to be significant, these animals can be prevented from reaching nests by attaching plastic sheeting to the trunks of nest trees. Such conservation measures are simple yet are likely to provide the best immediate means of conserving the White-shouldered Ibis.

For further information contact hugh.wright@uea.ac.uk

Project Update: August 2010

The 2010 breeding season finished in May with white-shouldered Ibis having a productive year.

We successfully installed our nest cameras at four ibis nests, getting a total of 165 days of coverage. Installing cameras was not easy with challenges including: minimising disturbance to the birds; finding climbable nest trees and sufficiently visible nests; preventing human, livestock and wild animal interference; and also avoiding forest fires! Despite these, we were able to develop an installation technique that has proved successful on nests at the young chick or late incubation stages. While this year’s higher productivity was good news for ibis, our cameras did not capture any predation events. Predation is likely to naturally vary between seasons and we are hopeful that next season we will get recordings of the predators. A southern jungle crow was seen scavenging eggs from an abandoned ibis nest and so this species remains a likely predator.

Project Update: December 2010

The 2011 breeding season is now underway, with white-shouldered ibis pairing up, courting, mating, nest building and egg-laying. Local field staff have already found several nests where incubation has begun so shortly we’ll begin installing nest cameras for a second season. Nest cameras are not installed until the nest has been incubated for at least 2 weeks to reduce the risk of desertion by the adults. For this season we have purchased extra equipment and better climbing gear to make installing and maintaining the camera systems easier. It will be interesting to see if predation plays a greater role in the survival of eggs and chicks than last season when breeding success was very high.

Final Report

Read more about the activities undertaken and findings of this project in the final report below.

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Final Report709 KB

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