Is floating and wading, a common behavior of Indian pond heron (Ardeola grayii)?

Abstract

The Indian pond heron or Paddy bird (Ardeola grayii) is a small heron belonging to the family Ardeidae. Ponds, streams, marshy wetlands are the major feeding habitat of the Indian pond heron and usually they feed at the edges of water bodies. While conducting behavioural studies of wetland birds in Kole wetlands of Thrissur, Kerala (10° 20′ & 10° 40′ N and 75° 58′ & 76° 11′ E), on 8th August 2016, an Indian pond heron was seen floating and wading in running water (water depth at 110 cm) from Pullazhi Kole (10° 20′ 46.27” & 76° 9′ 17” E), Thrissur. A mixed flock of Indian pond heron, Kingfishers and Cormorants were seen standing on the edge of the canal, suddenly when the motor pump started to dewater the canal, an Indian pond heron jumped into the water and was seen floating along the wate r and wading, without the support of any floating vegetation. It continued the floating for about 2.7 minutes, till it touched the shutter and flew away. The increased population during the breeding season and reduced foraging areas due to decreased rainfall lead to interspecific competition. Both the Little cormorant and the Indian pond heron being piscivorous birds, several instants of competition for foraging area were observed. As fishes in the canal move along with the flowing water and congregate near the net placed near the shutter, it would be easy to wade and catch the fish. This may be the reason behind such a floating and wading behaviour of the Indian pond heron.

Keywords: Indian pond heron, Paddy bird, Ardeola grayii

Introduction

The Indian pond heron or Paddy bird ( Ardeola grayii ) is a small heron belonging to the family Ardeidae. Ponds, streams, marshy wetlands are the major feeding habitat of Indian pond heron and usually they feed at the edges of water bodies. Sometimes they make use of floating vegetation for catching fish from deep water. While conducting behavioural studies of wetland birds in Kole wetlands of Thrissur, Kerala (10° 20′ & 10° 40′ N and 75° 58′ & 76° 11′ E), on 8 th August 2016, an Indian pond heron was seen floating and w ading in running water (water depth at 110 cm) from Pullazhi Kole (10° 20′ 46.27” & 76° 9′ 17” E), Thrissur. The activities of the Indian pond heron was observed using binocular (10x -45 x). A mixed flock of Indian pond heron, Kingfishers and Cormorants were seen standing on the edge of the canal, suddenly when the motor pump started to dewater the canal, an Indian pond heron jumped into the water and was seen floating along the water and wading, without the support of any floating vegetation. It continued the floating for about 2.7 minutes, till it touched the shutter and flew away. Various studies regarding foraging (Kirkpatrick, 1953), bellyflopping (Muir, 1916), fly and capture behavior (Grimwood et al., 1984; Sivasubramanian, 1988), fish baiting using br ead crumps (Reglade et al ., 2015), feeding of dragonflies (Santharam, 2003), earthworms (Raza, 1993), bees (Prasad et al ., 1992) and scavenging behavior (Roshnath, 2015) of the Indian pond heron was described by earlier workers. Even though the floating behavior of the Indian pond heron was observed in closed water bodies; tanks and ponds (Neelakantan, 1986), but such behavior in running water was not reported earlier.

Kole wetland is a Ramsar site which abodes a wide variety of resident as well as migrat ory birds. The increased population during the breeding season and reduced foraging areas due to decreased rainfall lead to interspecific competition. Both the Little cormorant and the Indian pond heron being piscivorous birds, several instants of competition for foraging area was observed. As fishes in the canal move along with the flowing water and congregate near the net placed near the shutter, it would be easy to wade and catch the fish. This may be the reason behind such a floating and wading behaviour of the Indian pond heron.

Acknowledgements

The authors are grateful to the Director, KFRI for the facilities and infrastructure. We wish to thank KSCSTE for providing necessary financial support. Special thanks to Jinoy for rendering field support.

References

1. Ali S , Ripley SD. Hand book of the Birds of India and Pakistan . Oxford University Press, Oxford. 1983, 466.
2. Grimwood IM, Brocklehurst MJC. Unusual feeding behaviour in the Paddy Bird or Indian Pond Heron Ardeola grayii . Journal of Bombay Natur al History Society. 1984; 81(3):696- 697.
3. Kirkpatrick KM. Feeding habit of the Indian Pond Heron ( Ardeola grayii ). Journal of Bombay Natural History Society. 1953; 51(2):507.
4. Muir GBF. Paddy -birds Ardeola grayii fishing. Journal of Bombay Natural History So ciety . 1916; 24(2):366- 367.
5. Neelakantan KK. Pond heron afloat. Newsletter for Birdwatchers. 1986; 26(5- 6):11 -13.
6. Prasad JN , Hemanth J. Pond Heron Ardeola grayii (Sykes) feeding on bees. Journal of Bombay Natural History Society. 1992; 89:246.
7. Raza RH. Pond Heron foraging on earthworms. Newsletter for Birdwatchers. 1993; 33(3):52- 53.
8. Réglade MA, Dilawar ME , Ulhas A. Active bait -fishing in Indian Pond Heron Ardeola grayii . Indian Birds . 2015; 10(5):124- 125.
9. Roshnath R. Preliminary study in diet composition of Indian pond Heron during breeding season. International Journal of Biochemistry and Biotechnology. 2015; 4(5):574- 577.
10. Santharam V. Indian Pond -Herons Ardeola grayii feeding on Dragonflies. Journal of Bombay Natural History Society . 2003; 100(1):108.
11. Sivas ubramanian C. Aerial feeding by Median Egret ( Egretta intermedia ), Little Egret ( Egretta garzetta ) and Pond Heron ( Ardeola grayii ). Journal of Bombay Natural History Society. 1988; 85(3):611- 612.