Bird flu: Threat of infection to migratory birds

New Delhi : Thousands of exotic migratory birds are set to fly in the capital and surrounding places grappling with Avian influenza, sending alarm bells ringing among wildlife experts who warn that it would be difficult to curb the mess if the visitors contract the virus.

The National Zoological Park, which has been shut down temporarily over the death of 12 water birds due to H5 Avian Influenza, is bracing for the migratory season this winter, wherein thousands of exotic birds from different countries flock to the zoo for breeding.
Wildlife experts claimed that extra caution needed to be taken when exotic birds descend to the zoo amid a bird flu scare.

“Exotic birds transcend from their places of origin to various wetlands of India during the winters. They also cohabit during migratory season, thus making it easy for the infection to spread. Thus extra caution needs to be taken,” ecologist Vinay Menon said.

He said it would be difficult to curb the mess if any exotic species contract the virus, thus the “zoo needs to be sanitised thoroughly before the migratory season begins next month.”

Zoo curator Riyaz Khan told PTI, “The migratory birds from Siberia and southeast Asia come to Delhi zoo every year for breeding during November-December. The migratory pattern may get disrupted due to climate change, delayed onset of winter or a ban on hunting in countries en route to the city.”

As per an informal enquiry conducted by the zoo officials into the recent deaths of 12 water birds, including painted storks, pelicans and ducks, it came to the fore that the “pathogenic strains” of the H5 Avian Influenza might have been carried by local migratory birds.

A zoo official had claimed that the chances of the resident birds contracting the virus were meek.

“The chances of the migratory birds carrying the pathogenic strains are very likely, though a conclusion cannot be made without analysing specific cases. In the meantime, we are taking all steps for the upcoming migratory season wherein thousands of exotic birds fly to the zoo,” Dr Abhijeet Bhawal, Veterinary officer told PTI.

Delhi Zoo houses around 642 birds of 51 different species (as per 2015 inventory report). Exotic birds like Dabchik, Northen Pintail, Common Teal, Red Lapwing, Coot, Shoveller Duck come to the zoo for breeding.

White Ibis, Night Heron, painted storks, Tailor bird, green pigeon, Blue-throated Crystal, Spot billed ducks are some of the local winter visitors at the park.

The zoo, one of the largest in the country, has been hit by a spate of animal deaths in the recent past. It lost 46 spotted deer to rabies in January, while 12 water birds died last week. It also lost its sole King Cobra recently.

The Centre had yesterday formed a three-member committee to keep a constant vigil around the park, as well as monitor and contain the H5 Avian Influenza.

A total of 40 birds have died of the Influenza in the national capital since October 14. While 12 deaths were reported at the Delhi zoo, 28 ducks died at the Hauz Haas Deer Park. A death was also reported from the Asola Bhatti Wildlife Sanctuary.

The Department of Animal Husbandry, Dairying and Fisheries at the Centre had on Friday said a new bird flu virus subtype, H5N8, has been confirmed in samples from Gandhi Zoological Park, Gwalior.

The government has also issued an advisory to all wildlife/bird sanctuaries in this regard.
Among the 12 water birds, which died at the Delhi zoo, the majority were the local migratory painted storks. Ironically, the zoo had in January this year achieved a record breeding programme of the species, with the painted storks laying around 1,800 eggs.
The large wading birds usually migrate from Kufri and Pong Dam regions of Himachal Pradesh. Monsoon is the best time for their survival andtheir diet depends on rainfall. They usually feed on fishes.

The National Zoological Park receives a batch of 800-1,000 painted storks every year.
“Light wooden sticks are thrown around the bird enclosures for the storks to make nests. The painted storks generally make their own nests. This time we ran out of nests and found the eggs being laid even in the chimpanzee and Nilgai enclosures,” Khan said.

Explaining the peculiar nature of the wading birds, the curator said the parent painted storks fly back to their native place leaving behind the eggs. The young ones that take 16 weeks to mature go back to their parents with the help of a “strong smelling power”.

“The adult storks can be identified by their yellow beaks while the younger ones have grey beaks. The beak color can turn into a dim shade due to the pollution level of the area they migrate to. Painted storks form nesting colonies in areas full of moss, as they are also fond of insects,” the official said.

Delhi zoo and Bharatpur Bird Sanctuary in Rajasthan are the places where these birds come for breeding and nesting.