Oriental Pratincole – flocks and thermals

posted in: Feeding strategy, Miscellaneous | 0

“I had an opportunity to watch Oriental Pratincoles (Glareola maldivarum) today. They congregate at this wetland site in large numbers. I counted birds (using images, intentionally underestimate) and one flock alone, on the ground, was 260 birds with a sizable number being first winter birds.

“The above shows a small section of this flock. There were other birds scattered all round and some flocks in the air (below). Hence the actual number exceeds 400 birds.

“Oriental Pratincoles are known to feed on insects in the air and possibly on the ground. But of interest to me is their behaviour of soaring with the thermals.

“I saw this behaviour again today (see image above, taken at 10.30am). When they soar really high up, they look so much like raptors from below. In trying to understand this behaviour, I came across some opinions.

“Higgins & Davies (1996) state that ‘Flocks of thousands of birds ascend in thermals near cyclonic storms to feed on insects and other prey sucked up by thermals…

“Bergin & Finger (2013) describe observations where ‘Oriental Pratincoles …. are usually seen in large flocks in Australia …. They can be seen roosting on the beaches in the heat of the day or swirling up in the sky like a smoke plume as they take advantage of the thermals.’

“Biota Environmental Sciences (2018) quoting various sources, offers the best information, and states ‘Oriental Pratincoles are known to regularly use thermal soaring in north-western Australia (Piersman & Hassell 2010) …. they report an observation of thermal soaring 600-700 meters above ground …. The reasons for this behaviour have not been documented; however, the description of the birds gliding in circles (Piersma and Hassell 2010) suggests that they were not actively foraging. The regular use of thermals by Oriental Pratincoles during the heat of the day suggests that they may be using altitude as a thermal refuge, as air temperatures at such altitudes may be 2-3 ºC cooler than at ground level (Livingstone et al. 1999).’

“I tend to agree with the last observation. They appear to be circling high up and unlikely to be feeding. They could also be using the thermals to gain altitude and move to other feeding sites.”

Dato’ Dr Amar-Singh HSS
Ipoh, Perak, Malaysia
10th October 2019

Location: Malim Nawar Wetlands, Perak, Malaysia
Habitat: Extensive ex-tin mining area with pond/lakes, wetlands, fish farming

References:
1.
Biota Environmental Sciences. 2018. Asian Renewable Energy Hub Migratory Shorebirds and Waterbirds Survey. Prepared for NW Interconnected Power. November 2018 (available HERE).
2. Higgins, P.J. & Davies, S.J.J.F. (editors) 1996. Handbook of Australian , New Zealand & Antarctic Birds. Volume 3, Snipe to pigeons. Melbourne, Oxford University Press. Vol. 2, pages 648-649, Vol. 3, pages 365-373; plate 23 (available HERE).
3. Mike Bergin & Corey Finger. 2013. 10,000 Birds website: Oriental Pratincoles (available HERE).

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