The hunt for the Philippine Ducks

Beth Roberts

Wetlands are important habitats for flood prevention, erosion control, water purification, and shoreline protection. They are also a carbon sink, and play an important role in supporting a rich diversity of resident and migratory species. However, these habitats are under increasing threat from expanding agriculture, pollution and overfishing.

The conversion of wetlands to agriculture is placing many species under increasing threat of extinction (Photo: Beth Roberts).

The Philippines is among 25 ‘megadiversity’ hotspots in the world (those areas that contain the majority of the world’s species) and has been placed within the two ‘hottest of hotspots’ owing to its high levels of endemism (those species that are unique to a particular geographic location) (>47% of vertebrates and >76% plants). However, this rich biodiversity does not translate into increased measures of conservation action, with 33% of the country’s 181 endemic birds classified as threatened, the second highest total of any country. One such threatened species is the Philippine Duck (Anas luzonica). The research that I have done during my PhD examines the biases in published wildfowl demographic research (see http://stuartmarsden.blogspot.co.uk/2014/01/macro-demography-and-conservation-of_18.html), and highlights the importance of conducting studies in areas with limited knowledge, such as the Philippines.

To gather vital basic ecological and habitat requirements of the Philippine Duck, I visited the Philippines with funding received from two MMU awards: A Careers and Development Award and a Conference Award. The money paid for my flights, conference fees, accommodation and travel costs. Whilst in the Philippines, I attended the World Conservation Society Symposium in Cebu where I met many researchers and gathered vital demographic information on the Philippine Duck. Dr Carmela Española (formally a PhD

student at MMU who worked on frugivores with Dr Stuart Marsden and I visited four wetland habitats.

Philippine Duck (Anas luzonica) (Photo: Nic Cabigas)

We first visited Candaba Marsh, Luzon (categorised an Important Bird Areas ; an important wetland site for resident waterbirds and migratory species. Here, large numbers of Wandering Whistling-duck Dendrocygna arcuata and Philippine Duck were present, along with many other wetland bird species. We recorded over 300 Philippine Duck at the site, and whilst interviewing local farmers we also observed a man standing on a water buffalo collecting what were potentially Philippine Duck eggs.

The habitat surrounding Candaba Bird Sanctuary is predominantly rice fields (Photo: Beth Roberts)

We also conducted a site visit to the river mouth at Subic Bay, Luzon, which has historically recorded 400 Philippine Ducks congregating in a large group in the mangroves. We found no ducks, but were able to gather valuable nesting and habitat data from the local people.

The mangrove area at Subic Bay (Photo: Beth Roberts).

Our third site was Naujan Lake (14,568 ha) in Mindoro, designated a Ramsar site (wetlands of international importance and designated under the Ramsar Convention);the fifth largest lake in the Philippines. The lake supports large numbers of ducks and other waterbirds. The duck may occur at low densities due to the availability of many suitable wetland habitats or as a consequence of increased hunting pressure from the local people that live next to the lake.

Naujan Lake, Mindoro Island (Photo: Beth Roberts).

The final site was Las Piñas-Parañaque Critical Habitat and Ecotourism Area (175 ha), a coastal wetland within Metro Manila, and also designated a Ramsar site. The area supports large numbers of resident and migratory birds, including the Vulnerable Chinese Egret Egretta eulophotes) and is also a breeding site for the Philippine Duck. We found 25 Philippine Duck using the shallow lagoons within the mangrove forest.

As a direct consequence of my research trip to the Philippines I am in the process of setting up a project to discover more about the poorly-understood Philippine Duck.The project sets out to :

1) Conduct surveys at wetland sites to assess the distribution, abundance and habitat use of the Philippine Duck

2) Gather information on other wetland bird species 3) Assess hunting pressure and egg collection rates by conducting interviews.

If you would like to know more about the Philippine Duck Project please contact Beth Roberts at b.roberts@mmu.ac.uk. Collaborating on the project are Dr Carmela Española, University of the Philippines, Dr Stuart Marsden, Manchester Metropolitan University and Dr Matt Geary, University of Chester.