Journal Home > Volume 6 , Issue 1
Background

Food abundance and availability affect flock patterns of foraging birds. Cost and risk tradeoffs are especially critical for flocks of wintering waterbirds foraging in lake wetlands. Waterbirds losing suitable habitats face insufficient food supplies and high levels of disturbance, affecting their foraging activities. Our Objective was to study the effects of food abundance and disturbances on flock size and the structure of Hooded Crane flocks wintering at Shengjin Lake and, as well, to understand the response of wintering waterbirds to habitat degradation for future management decisions and protection of the population.

Methods

We investigated food abundance, disturbances and flock foraging activities of the wintering Hooded Crane in several foraging habitats of Shengjin Lake from November 2013 to April 2014. Flock size and structure were observed by scan sampling. Data on food abundance and disturbances were collected by sampling. Flock size and structure were compared among three wintering stages. The relationship between food resources, disturbances and flock size were illustrated using a generalized linear model.

Results

In the early and middle wintering periods, the Hooded Crane used paddy fields as its major foraging habitat, where the number of foraging birds and flocks were the highest. During the late period, the cranes took to meadows as their major foraging habitat. The variation among foraging flock was mainly embodied in the size of the flocks, while the age composition of these flocks did not change perceptibly. Family flocks were notably different from flock groups in size and age composition. The Results of a generalized linear model showed that the food abundance had a marked effect on foraging flock size and age composition, while disturbances had a significant effect only on flock size. From our analysis, it appeared that the combined effect of the two variables was significant on the size of the foraging flock, but had less impact on age composition.

Conclusions

Food abundance and disturbances affected the flock size of the Hooded Crane. With abundant food and high disturbances, flock sizes increased owing to cooperation in foraging. To avoid competition and maximize foraging benefits, flock size reduces with an abundance of food but low disturbance. By trading off risks and costs, the cranes showed flexible flock distributions and a variety of foraging strategies to maximize benefits and to improve their fitness.


menu
Abstract
Full text
Outline
About this article

The effects of food abundance and disturbance on foraging flock patterns of the wintering Hooded Crane (Grus monacha)

Show Author's information Ling Yang1,2,3Lizhi Zhou1,2,3( )Yunwei Song4
School of Resources and Environmental Engineering, Anhui University, Hefei 230601, China
Institute of Biodiversity and Wetland Ecology, Anhui University, Hefei 230601, China
Anhui Biodiversity Information Center, Hefei 230601, China
Shengjin Lake National Nature Reserve of Anhui Province, Dongzhi 247200, China

Abstract

Background

Food abundance and availability affect flock patterns of foraging birds. Cost and risk tradeoffs are especially critical for flocks of wintering waterbirds foraging in lake wetlands. Waterbirds losing suitable habitats face insufficient food supplies and high levels of disturbance, affecting their foraging activities. Our Objective was to study the effects of food abundance and disturbances on flock size and the structure of Hooded Crane flocks wintering at Shengjin Lake and, as well, to understand the response of wintering waterbirds to habitat degradation for future management decisions and protection of the population.

Methods

We investigated food abundance, disturbances and flock foraging activities of the wintering Hooded Crane in several foraging habitats of Shengjin Lake from November 2013 to April 2014. Flock size and structure were observed by scan sampling. Data on food abundance and disturbances were collected by sampling. Flock size and structure were compared among three wintering stages. The relationship between food resources, disturbances and flock size were illustrated using a generalized linear model.

Results

In the early and middle wintering periods, the Hooded Crane used paddy fields as its major foraging habitat, where the number of foraging birds and flocks were the highest. During the late period, the cranes took to meadows as their major foraging habitat. The variation among foraging flock was mainly embodied in the size of the flocks, while the age composition of these flocks did not change perceptibly. Family flocks were notably different from flock groups in size and age composition. The Results of a generalized linear model showed that the food abundance had a marked effect on foraging flock size and age composition, while disturbances had a significant effect only on flock size. From our analysis, it appeared that the combined effect of the two variables was significant on the size of the foraging flock, but had less impact on age composition.

Conclusions

Food abundance and disturbances affected the flock size of the Hooded Crane. With abundant food and high disturbances, flock sizes increased owing to cooperation in foraging. To avoid competition and maximize foraging benefits, flock size reduces with an abundance of food but low disturbance. By trading off risks and costs, the cranes showed flexible flock distributions and a variety of foraging strategies to maximize benefits and to improve their fitness.

Keywords: Hooded crane, Flock pattern, Food abundance, Disturbance

References(61)

Abramsky Z, Strauss E, Subach A, Kotler BP, Reichman A. 1996. The effect of barn owls (Tyto alba) on the activity and microhabitat selection of Gerbillus allenbyi and G. pyramidum. Oecologia, 105(3):313-319

Alonso JC, Bautista LM, Alonso JA. 2004. Family-based territoriality vs flocking in wintering Common Cranes (Grus grus). J Avian Biol, 35(5):434-444

Altmann J. 1974. Observational study of behavior: sampling methods. Behaviour, 49(3):227-267

Avilés JM. 2003. Time budget and habitat use of the Common Crane wintering in Dehesas of southwestern Spain. Can J Zool, 81(7):1233-1238

Avilés JM, Bednekoff PA. 2007. How do vigilance and feeding by common cranes Grus grus depend on age, habitat, and flock size? Avian Biol, 38(6):690-697

Azevedo CS, Ferraz JB, Tinoco HP, Young RJ, Rodrigues M. 2010. Time-activity budget of greater rheas (Rhea americana, Aves) on a human-disturbed area: the role of habitat, time of the day, season and group size. Acta Ethol, 13(2):109-117

Bahr DB, Bekoff M. 1999. Predicting flock vigilance from simple passerine interactions: modelling with cellular automata. Anim Behav, 58:831-839

Barta Z, Liker A, Mónus F. 2004. The effects of predation risk on the use of social foraging tactics. Anim Behav, 67:301-308

Barter M, Chen LW, Cao L, Lei G. 2004. Waterbird Survey of the Middle and Lower Yangtze River Floodplain in Late January and Early February 2004. China Forestry Publishing House, Beijing

Baschuk MS, Koper N, Wrubleski DA, Goldsborough G. 2012. Effects of water depth, cover and food resources on habitat use of marsh birds and waterfowl in boreal wetlands of Manitoba, Canada. Waterbirds, 35(1):44-55

Beauchamp G. 2005. Does group foraging promote efficient exploitation of resources? Oikos, 111(2):403-407

Beauchamp G. 2009. How does food density influence vigilance in birds and mammals? Anim Behav, 78:223-231

Beauchamp G. 2012. Foraging speed in staging flocks of semipalmated sandpipers: evidence for scramble competition. Oecologia, 169(4):975-980

Beauchamp G. 2013. Social foragers adopt a riskier foraging mode in the centre of their groups. Biol Lett, 9(6):1-3

Bekoff M. 1995. Vigilance, flock size, and flock geometry: information gathering by western evening grosbeaks (Aves, Fringillidae). Ethology, 13:150-161

BirdLife International. 2014. Grus monacha. In: IUCN 2014. The IUCN Red List of Threatened Species. Version 2014.3., http://www.iucnredlist.org

Bishop MA, Li FS. 2002. Effects of farming practices in Tibet on wintering Black-necked Crane (Grus nigricollis) diet and food availability. Biodiv Sci, 10(4):393-398

Brown JS, Kotler BP. 2004. Hazardous duty pay and the foraging cost of predation. Ecol Lett, 7(10):999-1014

Cai TL, Huettmann F, Guo YM. 2014. Using stochastic gradient boosting to infer stopover habitat selection and distribution of Hooded Cranes Grus monacha during spring migration in Lindian, Northeast China. PLoS One, 9(2):1-12

Chen JY, Zhou LZ. 2011. Guild structure of wintering waterbird assemblages in shallow lakes along Yangtze River in Anhui Province, China. Acta Ecol Sin, 31(18):5323-5331

Cong P, Rees EC, Sun MM, Mj Z, Cao L, Barter M. 2011. A comparison of behaviour and habitat use by Bewick's Swans Cygnus columbianus bewickii at wintering sites in China and Europe: preliminary observations. Wildfowl, 61:52-73

Conradt L. 1998. Measuring the degree of sexual segregation in group-living animals. J Anim Ecol, 67:217-226

Czech HA, Parsons KC. 2002. Agricultural wetlands and waterbirds: a review. Waterbirds, 25:56-65

Elgar MA. 1989. Predator vigilance and group size in mammals and birds: a critical review of the empirical evidence. Biol Rev, 64:13-33

Fox AD, Cao L, Zhang Y, Barter M, Zhao MJ, Meng FJ, Wang SL. 2011. Declines in the tuber-feeding waterbird guild at Shengjin Lake National Nature Reserve, China - a barometer of submerged macrophyte collapse. Aquat Conserve, 21(1):82-91

Fuller RA, Bearhop S, Metcalfe NB, Piersma T. 2013. The effect of group size on vigilance in Ruddy Turnstones Arenaria interpres varies with foraging habitat. Ibis, 155(2):246-257

Gyimesi A, Franken MS, Feige N, Nolet BA. 2012. Human disturbance of Bewick's Swans is reflected in giving-up net energy intake rate, but not in giving-up food density. Ibis, 154(4):781-790

Hansen BB, Aanes R, Herfindal I, Sæther BE, Henriksen S. 2009. Winter habitat-space use in a large arctic herbivore facing contrasting forage abundance. Polar Biol, 32(7):971-984

Heithaus MR. 2005. Habitat use and group size of pied cormorants (Phalacrocorax varius) in a seagrass ecosystem: possible effects of food abundance and predation risk. Mar Biol, 147(1):27-35

Heithaus MR, Dill LM. 2002. Food availability and tiger shark predation risk affects bottlenose dolphin habitat use. Ecology, 83:480-491

Jiang HX, Xu WB, Qian FW, Chu GZ. 2007. Impact of habitat evolvement and human disturbance on wintering water birds in Shengjin Lake of Anhui Province, China. Chin J Appl Ecol, 18(8):1832-1836

Jing K, Ma ZJ, Li B, Li JH, Chen JK. 2007. Foraging strategies involved in habitat use of shorebirds at the intertidal area of Chongming Dongtan, China. Ecol Res, 22(4):559-570

Kotler BP, Brown JS, Hasson O. 1991. The specter of predation: factors affecting gerbil foraging behavior and rates of owl predation. Ecology, 72(6):2249-2260

Kuwae T, Miyoshi E, Sassa S, Watabe Y. 2010. Foraging mode shift in varying environmental conditions by dunlin Calidris alpina. Mar Ecol Prog Ser, 406:281-289

Li CL, Zhou LZ, Li HK, Jiang ZG. 2011. Effects of foraging mode and group pattern on vigilance behavior in water birds: a case study of mallard and black-winged stilt. Belg J Zool, 141(2):45-54

Li HC, Ding TS, Tsai CF, Hsu FH. 2012. Effects of habitat type and group size on foraging and vigilance behaviors of the Red Collared Dove Streptopelia tranquebarica. Taiwania, 57(2):99-105

Lima SL. 1998. Stress and decision making under the risk of predation: recent developments from behavioral, reproductive, and ecological perspectives. Adv Stud Behav, 27:215-290

Lima SL, Dill LM. 1990. Behavioral decision making under the risk of predation: a review and prospectus. Can J Zool, 68(4):619-640

Liu ZY, Xu WB, Wang QS, Shi KC, Xu JS, Yu GQ. 2001. Environmental carrying capacity for over-wintering Hooded Cranes in Shengjin Lake. Resour Environ Yangtze Basi, 10(5):454-459

Liu Q, Yang XJ, Zhu JG, Zhao JL, Yu HZ. 2008. Flock of black-necked crane wintering at Napahai nature reserve, China. Zool Res, 29(5):553-560

Luo JM, Wang YJ, Yang F, Liu ZJ. 2012. Effects of human disturbance on the Hooded Crane (Grus monacha) at stopover sites in northeastern China. Chinese Birds, 3:206-216

Ma ZJ, Li B, Jing K, Zhao B, Tang SM, Chen JK. 2003. Effects of tidewater on the feeding ecology of Hooded Crane (Grus monacha) and conservation of their wintering habitats at Chongming Dongtan, China. Ecol Res, 18(3):321-329

Macdonald EC, Ginn MG, Hamilton DJ. 2012. Variability in foraging behavior and implications for diet breadth among Semipalmated sandpipers staging in the upper bay of Fyndy. Condor, 114(1):135-144

Masatomi H. 2004. Individual (non-social) behavioral acts of Hooded Cranes (Grus monacha) wintering in Izumi, Japan. J Ethol, 22:69-83

Michelena P, Deneubourg JL. 2011. How group size affects vigilance dynamics and time allocation patterns: the key role of imitation and tempo. PLoS One, 6(4):1-9

Nystrand M. 2006. Influence of age, kinship, and large-scale habitat quality on local foraging choices of Siberian Jays. Behav Ecol, 17:503-509

Santangeli A, Dolman PM. 2011. Density and habitat preferences of male little bustard across contrasting agro-pastoral landscapes in Sardinia (Italy). Eur J Wildl Res, 57(4):805-815

Severcan Ç, Yamac E. 2011. The effects of flock size and human presence on vigilance and feeding behavior in the Eurasian Coot (Fulica atra) during breeding season. Acta Ethol, 14(1):51-56

Sirot E, Maes P, Gélinaud G. 2012. Movements and conflicts in a flock of foraging Black-Tailed Godwits (Limosa limosa): the influence of feeding rates on behavioural decisions. Ethology, 118(2):127-134

Terence PB, Sandra MC, Robert GW. 2004. Landsat TM inventory and assessment of waterbird habitat in the southern altiplano of South America. Wetland Ecol Manage, 12:563-573

Wang QS. 1988. The Hooded Cranes. Chin J zool, 23(4):30-34

Wang K, Yang XJ, Zhao JL, Yu HZ, Min L. 2009. Relations of daily activity patterns of age and flock of wintering Black-necked Crane (Grus nigricollis) at Napa Lake, Shangri-La in Yunnan. Zool Res, 30:74-82

Wang Z, Li ZQ, Beauchamp G, Jiang ZG. 2011. Flock size and human disturbance affect vigilance of endangered red-crowned cranes (Grus japonensis). Biolog Conserv, 144(1):101-105

Wood C, Qiao Y, Li P, Ding P, Lu BZ, Xi YM. 2010. Implications of rice agriculture for wild birds in China. Waterbirds, 33(1):30-43

Xu LL, Xu WB, Sun QY, Zhou ZZ, Shen J, Zhao XX. 2008. Flora and vegetation in Shengjin Lake. J Wuhan Bot Res, 27(3):264-270

Xu F, Ma M, Yang WK, Blank D, Ding P, Zhang T. 2013. Vigilance in Black -Necked Cranes: effects of predation vulnerability and flock size. Wilson J Ornithol, 125(1):208-212

Yasué M. 2005. The effects of human presence, flock size and prey density on shorebird foraging rates. J Ethol, 23(2):199-204

Yasué M, Quinn JL, Cresswell W. 2003. Multiple effects of weather on the starvation and predation risk tradeoff in choice of feeding location in redshanks. Funct Ecol, 17:727-736

Zhao FT, Zhou LZ, Xu WB. 2013. Habitat utilization and resource partitioning of wintering Hooded Cranes and three goose species at Shengjin Lake. Chinese Birds, 4(4):281-290

Zhou B, Zhou LZ, Chen JY, Xu WB, Cheng YQ. 2009. Assemblage dynamics and territorial behavior of Hooded Cranes wintering in Shengjin Lake. Chin Wildlife, 30(3):133-136

Zhou B, Zhou LZ, Chen JY, Cheng YQ, Xu WB. 2010. Diurnal time-activity budgets of wintering Hooded Cranes (Grus monacha) in Shengjin Lake, China. Waterbirds, 33(1):110-115

Publication history
Copyright
Acknowledgements
Rights and permissions

Publication history

Received: 02 March 2015
Accepted: 02 June 2015
Published: 12 August 2015
Issue date: January 2015

Copyright

© 2015 Yang et al.

Acknowledgements

The work was supported by the staff of the Shengjin Lake National Nature Reserve. We express appreciation to the National Natural Science Foundation of China (Grant no. 31172117, 31472020) and the Graduate Student Innovation Research Projects of Anhui University (YQH100270) for financial support. We thank Meng Zheng and Dr. Chunlin Li for their helpful comments and suggestions for this study.

Rights and permissions

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Return