Papua harrier studies (Papua New Guinea)

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Papua harrier in flight

The adult Papua harrier is a striking grey and white bird that, like other harriers, quarters over grasslands searching for birds and rodents.

Natural Research has partnered with Rob Simmons, of the Fitzpatrick Institute (South Africa) to study the world's poorest known harrier, the Papua harrier (Circus spilothorax), in New Guinea. Rob teamed up with local raptor specialist Leo Legra (who also studied the New Guinea Harpy Eagle), for 3 weeks in 2007 to assess its population size, threats and genetic status.

The Papua harrier is purported to be a subspecies of the common and widespread eastern marsh harrier of eastern Russia, but its resident status on the island of New Guinea suggests otherwise.

Rob and Leo started their quest in Papua New Guinea's eastern highlands and found birds moving through the local airstrips into the higher areas. There feathers were collected for DNA analysis and the project shifted to the lowlands in the Markham and Ramu Valley.

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Pawa Limu, Environmental officer of the Ramu 
Sugar company, gets his first view of a Papua New 
Guinea Harrier chick - one that was later killed 
by fire sweeping the area

Two nests were found - only the second and third for this elusive species - in typical damp grassy areas close to agricultural fields. Both nests had three chicks each and remains of quail, rail and rats. Female size was gauged from egg size (only two eggs are known and measured) and suggest that this island form may rank as the world's largest harrier at 880 g.

From data carefully gathered over 3 days from these lowland valleys, they estimated about 6.5 harriers /100 sq. km, and extrapolating from that using the proportion of New Guinea with appropriate open marshy/grassland habitat gives the very first population estimate of 3600 birds and less than 800 nesting pairs. The main threat to these birds are wildfires. Both nests monitored were lost to fire - and satellite images indicate massive burning of these valleys throughout the dry season- when the harriers breed. While much more data is required to verify this, we suspect that the Papuan harrier is a Near Threatened or even a globally Vulnerable species urgently in need of conservation, including conservation education.

The following peer-reviewed publication has recently been produced from this research:

Simmons, R.E. and Legra, L.A.T. 2009. Is the Papuan Harrier a globally threatened species? Ecology, climate change threats and first population estimates from Papua New Guinea. Bird Conservation International 19: 1-13.

Simmons R.E. 2010. The nest, eggs and diet of the Papuan Harrier from Eastern New Guinea. J Raptor Research 44 (1): 12-18.

Of the 16 species of harrier in the world, more than a quarter (29%) are globally threatened because their main habitat (wetlands and grasslands) are under severe pressure everywhere, mainly from agriculture.

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For further information please contact Dr Rob Simmons: Rob.Simmons@uct.ac.za

Photos: R. Simmons

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