Resident Watch Environment

A heron at home on an IT corridor

A purple heron at the Sholinganallur Perumbakkam marshlands. Photo: Prince Frederick   

Waterbirds’ breeding cycles work on the same principle as time-tables. The odd day can shift the hour, even redefine it. That dreaded teacher has not reported for work. Hurrah! That makes it an extra hour at the ground shooting at the goalposts. It can also go the other way with the same dreaded teacher filling in for an absentee colleague through the week, taking an extra hour every day. Sigh!

Superimpose this idea on a waterbird’s breeding cycle. It stays sacrosanct till the “odd day” arrives, with too much rain or too little of it, shifting the season this way or the other.

Taking in the Sholinganallur Perumbakkam Marshlands, one wonders if this year the breeding season has shifted for some resident waterbirds. This wetland reflects what should be the prevalent picture in most sections of this region. There is sufficient water; and for this time of the year, the wetland looks full, particularly on its eastern side. By extension, food should be in reasonably good supply, if not found in plenty.

Handbook of the Birds of India and Pakistan (Volume 1) by Salim Ali and S Dillon Ripley puts down the eastern purple heron’s breeding season in north India as stretching from June to September-October. And in south India, from November to March. It is an echo of the time-table, inviolable except for that odd season. Local rain patterns and an unexpected bonanza from the skies can shift timelines. The November-March timeline cannot be applied strictly to localities in those parts of south India that are more intensely touched by the south-westerlies.

Ornithologist V Santharam touches upon an account from a friend about sighting a purple-heron parent followed by a train of chicks, at a place near Palaghat, as recently as the last week of July.

“That section must be getting the full blast of the south west monsoon,” Santharam adds, hinting at the primary cause of variations in local breeding timelines.

A purple heron parked in the aquatic vegetation at the Sholinganallur Perumbakkam Marshlands in July 2021. Photo: Prince Frederick

A purple heron parked in the aquatic vegetation at the Sholinganallur Perumbakkam Marshlands in July 2021. Photo: Prince Frederick  

So, given the continual showers from this SW monsoon in our parts, would the resident purple heron (ardea purpurea) be tempted to start its breeding cycle early in Chennai and surrounding areas? It is just a surmise, watching the purple herons put in longer diurnal hours at the Sholinganallur Perumbakkam Marshlands, stalking their prey in characteristic Zen-like stillness. Santharam thinks this conjecture need not be off the mark. It is a possibility that can be borne out by sustained observation.

Opportunistic breeding

“Waterbirds are opportunistic. There have even been times when they have nested as early as August in Vedanthangal when there are good rains. It all depends on the rainfall. Within that short period, they have to make use of the available resources. They are very flexible in that respect. You cannot say with hundred percent certainty that if the book says so, it has to be like that. There have been good rains here too — in Rishi Valley — and we have noticed that some of the waterbirds have come back,” Santharam elaborates.

A purple heron on the wing across the Sholinganallur Perumbakkam Marshlands. Photo: Prince Frederick 

A purple heron on the wing across the Sholinganallur Perumbakkam Marshlands. Photo: Prince Frederick   

While the question of this species opportunistically breeding early remains a question, there is sure ground to stand on where the purple herons of the OMR bio-region are concerned. For one, the species enjoys the the avian version of an advantage gained by some of its neighbours, the IT employees by virtue of not only working on the IT Corridor, but also making it home. It is just “walk to work” for them. So it is for the purple heron. The humongous Pallikaranai Marsh, patches along the Buckingham canal (particularly the one off the ECR Link Road at Akkarai) as it snakes between OMR and ECR, and of course, the Sholinganallur Perumbakkam Marshlands (which in fact is a spit of the Pallikaranai Marsh) offer reed beds and other thick and tall vegetation that make it conducive for this skulker of a bird to spend long hours hidden and stalking prey. eBird records prove the regularity with which the purple heron is seen in these biodiversity hotspots. It sends out a message about what reeds and other seemingly useless vegetation can do for bird habitats. It is also a reminder of what we possess and should not let go.

One can safely assume that purple heron engages in nesting activity in the dense reedbeds in these patches, unnoticed. Besides, the commendably-protected premises of NIOT with its trees, in Pallikaranai, serve as nuptial chamber, maternity ward and nursery from waterbirds. Sundaravel Palanivel, a birder from Kamakotti Nagar in Pallikaranai, brings a huge piece to the puzzle. He enjoys a vantage point in observing waterbirds that swim around in a body of water adjacent to the NIOT campus.

Fledglings and juveniles of waterbirds get introduced to the rough and tumble of the wild in this naturally formed pool. A majority of these young would have “birth certificates” linked to the campus. “Between January and March, the spot-billed pelican, painted stork, Eurasian spoonbill, black-headed ibis, grey heron and egrets must be breeding at NIOT, having started their nesting activity in November. My assumption is that the purple heron should also be breeding there. Through the month of July, behind my home, I was seeing four to five juvenile purple herons, possibly on their own for three months now. This pattern is noticed around this time every year,” notes Sundaravel.

There is a possibility that an odd pair of purple herons or two nest on the lower boughs of the trees. There is a greater likelihood that they build their homes on reed-beds at the Pallikaranai Marsh, in greater privacy.

This stand squares up with what is known about the species. While it is not averse to breeding in mixed breeding colonies of waterbirds, it maintains an air of froideur, seeking a patch of quiet even in the madding crowd.

Santharam observes: “Compared to other waterbirds, they do not seem to prefer nesting in large colonies. In most of the large breeding colonies in South India, you do not come across nests. The nests could be slightly away from the nesting site or lower down in the reedbeds.”

Salim Ali and S Dillon Ripley put this trait of the purple heron this way in Handbook of the Birds of India and Pakistan Volume 1: “When in mixed heronries with other species, shows a tendency to segregation into its own mohallas.”

That volume of the magnum opus also underscores the purple heron’s ability to turn screwpine trees (thalampoo), their leaves, into a breeding platform. With that, the OMR bio-region ticks another of the boxes for favourable breeding conditions for the purple heron. Tall, thick and closely-woven stands of screwpine trees present a bulwark around a section of Thaiyur lake. Have the purple herons found this potential home?

(Resident Watch discusses the resident birds of Chennai and its surrounding districts)


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Printable version | Sep 25, 2021 1:03:35 PM | https://www.thehindu.com/sci-tech/energy-and-environment/a-heron-at-home-on-an-it-corridor/article35673817.ece

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