Look out for collared crows in Hong Kong: new study says numbers are dwindling

Research suggests city has second largest population of the birds in the world, as hunting and pesticide use cause dip in mainland numbers

PUBLISHED : Wednesday, 02 August, 2017, 6:50pm
UPDATED : Wednesday, 02 August, 2017, 6:51pm

A Hong Kong-native wetland bird is much less numerous than had been thought, with its global population down to under 2,000 from an estimate of up to 30,000 just over a decade ago, according to a new study.

The research, published in the Asian ornithology journal Forktail, highlighted the plight of the collared crow, which faces multiple threats on the mainland, and which has its second largest population in Hong Kong.

It revealed that the bird’s global numbers had dwindled to 1,850, of which 362 were spotted in Hong Kong and 1,350 in mainland China.

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“In my 70 birdwatching trips to China, I only saw them once,” Paul Leader, director of a Hong Kong-based ecological consultancy AEC, who led the research, said.

Leader said the species had been persecuted on the mainland by hunting, the wildlife trade and the use of pesticides. He called for the species’ global risk status, as listed on the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species, to be boosted from “near threatened” to “vulnerable”, to promote better conservation.

The birds are black with white feathers around their necks extending to the breasts. They live in wetlands in East Asia, including mainland China and Vietnam.

The IUCN first listed the birds as “near threatened” in 2008, as it was estimated that their population was somewhere between 15,000 to 30,000.

According to the field surveys of the study’s research team in Hong Kong, Macau and Guangdong from 2003 to 2014, the collared crow population in Hong Kong accounts for almost 20 per cent of the species’ global count.

It is a resident species, meaning the birds do not migrate. Though its numbers have dropped in many places on the mainland, its largest habitat – home to 450 of the birds – is in the Dabie mountain range, which spills into Anhui, Henan and Hubei provinces.

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According to the IUCN, the best places to spot the birds in Hong Kong are Plover Cove and Deep Bay.

Yu Yat-tung, research manager of the Hong Kong Bird Watching Society, said crows are protected in the city by laws and wetland conservation schemes covering fishponds, which they favour as foraging and roosting sites.