Tuesday, 22 September 2015

The fall and rise and fall (?) of the Citron-crested Cockatoo

Posted by Stuart Marsden and Simon Valle

We have just returned from a workshop dedicated to the conservation management of the Citron-crested Cockatoo on the Indonesian island of Sumba. It is 23 years since Stu last visited the island of Sumba in Indonesia. Then, in 1989 and again in 1992, he spent several months collecting data for his PhD on Indonesian parrots and hornbills.

The Critically Endangered Citron-crested Cockatoo Cacatua sulphurea citrinocristata (Photo: Peter Widman)

On both occasions, he was working as part of Martin Jones’ Manchester Indonesian Islands Expedition team, itself a winner of the BP Conservation awards (the predecessor of the CLP Programme outlined in the last blog post on Colombian birds). While the main aim of the expedition was to assess forest quantity and quality and examine distribution, abundance and habitat associations of the island’s endemic birds (e.g. Jones et al. 1995; Jones et al. 2003), his primary job was to collect data on the islands five parrots and the endemic Sumba Hornbill Rhyticeros everetti.

Large numbers of Citron-rests left the island in the 1980s (1992 Photo: Stu)
The PhD work focused on several aspects of the ecology of the birds: abundance and density estimation methods (Marsden 1999) and nesting ecology (Marsden & Jones 1997). The most pressing issue at the time was the incredibly heavy trade in the distinctive endemic race of Cacatua sulphurea, the Citron-crested Cockatoo C. s. citrinocristata (see blog post). During the 1970s and 1980s, perhaps as many as 2000 individuals were trapped annually on the island. By 1992, we estimated that were only around 3,200 left. We also found that trade was not the only grave threat to the cockatoo and other hole-nesting birds. Forest loss, through felling and burning, and loss of the huge nest trees selected by the parrots and hornbills were also serious threats both to the species on Sumba, and elsewhere in Indonesia.

These are the trees. Large trees of just a few species are absolutely crucial for the survival of Sumba's hole-nesting birds (Photo: Stu)

It appears that our efforts were timely and in 1992, there was a moratorium in trade in Citron-crests on Sumba. Of course, small numbers continued to appear in trade illegally during the 1990s but the reality was that the volume of trade was greatly reduced.

A man with a fishing rod stood next to another with a catapult in the forest can mean one thing - Cockatoo nest monitoring activities by staff from Burung Indonesian and National Parks in Sumba (Photos: Stu)

In 2002, Alexis Cahill, Jon Walker and Stu received grants from Loro Parque Fundacion and Wildlife Conservation Society to do some more work on Sumba. Primary goals of this work were to assess breeding output in the cockatoo, and to test the efficacy of nest box provision in the species (Walker et al. 2005), but especially, to see if 10 years of a trade ‘ban’ had had a positive effect on the cockatoo population. Four of the forest sites originally visited by Jones et al. in 1989/92 were revisited and parrots counted using the same methods, often on the same transects used previously. The results were, we believe, reasonably encouraging. Cockatoo density estimates had increased considerably at two sites, and risen modestly at a further site (Cahill et al. 2006). There was a statistically significant increase in abundance overall – something that biologists are rarely able to show in the world’s threatened species.
The workshop

Thirteen years on, and again there is concern for the cockatoo. There are anecdotal reports from a ZGAP-funded project suggesting that the cockatoo is declining again, in spite of years of awareness work, which is believed to have just about stopped illegal trade in the cockatoo. Low breeding output, perhaps by an ageing population, is one factor suspected by some. This prompted both the
Fonds für bedrohte Papageien-funded Sumba Cockatoo workshop and the new population study that Simon Valle and I plan for next year. 

2015 Sumba Cockatoo workshop participants, with organiser Thomas Arndt at the back, next to Simon

Burung Indonesia (the BirdLife Partner) and Thomas Arndt organised for many people who have, are, or will be working on the Sumba Cockatoos, to meet near Waikabubak  and confer about the conservation of the species. Participants ranged from the Burung Indonesia Sumba Team, who have been implementing an effective awareness programme for the last 10 years, to rangers from both of Sumba’s National Parks, to Anna Reuleaux, a biologist who has just started a one-year ZGAP-funded field research on the cockatoo’s breeding biology. The week-long workshop benefited hugely from the contribution of Thomas Arndt, ZGAP delegate and parrot expert, as well as of Peter and Indira Widman of the Katala Foundation who run the Philippine Cockatoo Conservation Programme, surely one of the most successful parrot conservation programmes in the world. 

One of my greatest conservation heroes - Peter Widman who, along with Indira Lacerna-Widman, run the Katala foundation in the Philippines (Photo: Stu)

Two main priorities were discussed - the need for a reliable population estimate, and the necessity of finding, surveying and protecting a sizable number of nests. Methods and results of previous surveys were analysed in order to identify possible issues and a new survey was devised (to be carried out from next April) in order obtain a reliable estimate of the current population size. We quickly realised how very little is known about their breeding productivity, and the factors that might affect it. This will be the focus of intensive fieldwork by Benny and the Burung team assisted by Anna in the next months. 

Cockatoo pair visiting nest tree (Photo: Peter Widman)

The workshop was a valuable opportunity to share the latest information on the species as well as some theoretical and practical knowledge on the most effective population survey and nest monitoring techniques. Finally there were promising talks with the staff from both the national parks about putting in place a regular long term monitoring scheme for the cockatoos implemented by park rangers.


Cahill, A.J., Walker, J.S. & Marsden, S.J. (2006). Recovery within a population of the Critically Endangered citron-crested cockatoo Cacatua sulphurea citrinocristata in Indonesia after 10 years of international trade control. Oryx 40: 161-167.

Jones M.J., Linsley, M.D. & Marsden, S.J. (1995). Population sizes, status and habitat associations of the restricted range bird species of Sumba, Indonesia. Bird Conservation International 5: 21-52.

Jones, M.J., Marsden, S.J. & Linsley, M.D. (2003). Effects of habitat change and geographical variation on the bird communities of two Indonesian islands. Biodiversity and Conservation 12: 1013-1032.

Marsden, S.J. (1999). Estimation of parrot and hornbill densities using a point count distance sampling method. Ibis 141: 377-390.

Marsden, S.J. & Jones, M.J. (1997). The nesting requirements of the parrots and hornbill of Sumba, Indonesia. Biological Conservation 82: 279-287. 

Walker, J.S, Cahill, A.J. & Marsden, S.J. (2005). Factors influencing nest-site occupancy and low reproductive output in the Critically Endangered Yellow-crested cockatoo Cacatua sulphurea on Sumba, Indonesia. Bird Conservation International 15: 347-360.



Saturday, 19 September 2015

Colombian birds and the Conservation Leadership Programme

 Posted by Stu

In July, I finally had the opportunity to visit the world’s most birdy country, Colombia. I was working with Conservation Leadership Programme (CLP) assisting a Colombian team with surveys of key birds on the Inter-Andean slopes EBA. CLP is a scheme which has, since 1985, funded, supported and trained promising conservationists from developing countries.

A target species, the Colombian endemic Chestnut Wood-quail Odontophorus hyperythrus (Photo: Fundación EcoAndina)
In recent years, the programme has supported young scientists from a wide range of biodiverse countries - for example, the scheme has supported over 200 projects in the Neotropics. Subjects and target species are also diverse (there is a great interactive map here). The programme also includes a fund to support visits by CLP alumni and ‘oldies’ like myself to assist the teams with their project planning, fieldwork and analysis.
Eliana and Diana using 'social cartography' to examine relationships between communities, land and wildlife across the sites identified at stakeholder meetings.

 My plan was to help Eliana Fierro-Calderon and Diana Eusse of the ‘Promoting conservation of threatened bird species in Western Colombia’ project to develop their field design for work on key birds in the Inter-Andean Slopes EBA. Eliana and Diana work at Calidris, a bird conservation NGO based in Cali, a large city in the Cauca Valley. They first won a CLP grant in 2008 and this current project extends that work on key birds.
The 'Vulnerable' Multicoloured Tanager Chlorochrysa nitidissima 'in the wild' (Photo: Calidris)

Their current project will involve visiting around six sites on the eastern slope of the Western Andes to calculate density estimates of birds and to examine their broad habitat associations. The sites include Cerro Dapa, Chicoral, El Cairo, Pueblo Rico and other sites where most forest remains (perhaps only 5% of original forest remains on this slope). They will use a point count distance sampling method to estimate bird abundance. 
The Endangered and tiny-ranged Cauca Guan Penelope perspicax (Photo: Diego Calderon)

Quick but detailed habitat information will be taken at each point, plus at places where the threatened species are found during informal birding forays and these will allow the team to examine differences between places the key species were recorded from a set of random points. An important component of the project is stakeholder involvement – and a key challenge will be to get the importance of the scientific information across to landowners for the benefit of local conservation. 

As well as trying to find out as much as possible about the threatened birds of the area, the team will also study a range of other, ‘commoner’ bird species in the sites. These include some species with specific ecosystem functional roles (e.g. frugivores as seed dispersers), species which might be hunted, birds which are easily recognisable or well-known by local people (e.g. motmots), and some understorey birds which might be seriously affected by forest quality changes. The list also includes some species related to the rare threatened species (e.g. Plain Antvireo, Red-eye Vireo, Chestnut-capped Brush-Finch) which might be used as ‘sister species’ to help model detectability in the rare species in Distance – to enable them to calculate some sort of density estimates for the threatened species, even with a small number of records. Surveys of rare birds should always consider including extra species in the fieldwork. In fifty years time, conservationists might well thank us for collecting data on today’s common species – some of these will be the threatened species of tomorrow for sure.

Some of the world's best birding can be done from roads crossing the Andes - like this, the old road at Anchicaya.

The trip included some nice birds of course. It was great to be able to visit Anchicaya for a couple of days with Anderson and Juan Carlos of Mapalina, a grassroots organisation connected with Calidris. It takes far longer than two days to do this Pacific slope site justice of course, but we managed some nice species including many tanagers, some puffbirds, and two species I’ve wanted to see for a long time, Scarlet-thighed Dacnis and Scarlet-and-white Tanager. The training itself was done at Chicoral, close to Cali, where the exquisite Multicoloured Tanager was frequent. Eliana and Diana head out into the field this week so best of luck to them.