River width and depth as key factors of diurnal activity energy expenditure allocation for wintering Spot-billed Ducks in the Xin'an River Basin

Rivers are important habitats for wintering waterbirds.However,they are easily influenced by natural and human activities.An important approach for waterbirds to adapt to habitats is adjusting the activity time and energy expenditure allocation of diurnal behavior.The compensatory foraging hypothesis predicts that increased energy expenditure leads to longer foraging time,which in turn increases food intake and helps maintain a constant energy balance.However,it is unclear whether human-disturbed habitats result in increased energy expenditure related to safety or foraging.In this study,the scan sample method was used to observe the diurnal behavior of the wintering Spot-billed Duck(Anas poecilorhyncha) in two rivers in the Xin’an River Basin from October 2021 to March 2022.The allocation of time and energy expenditure for activity in both normal and disturbed environments was calculated.The results showed that foraging accounted for the highest percentage of time and energy expenditure.Additionally,foraging decreased in the disturbed environment than that in the normal environment.Resting behavior showed the opposite trend,while other behaviors were similar in both environments.The total diurnal energy expenditure of ducks in the disturbed environment was greater than that in the normal environment,with decreased foraging and resting time percentage and increased behaviors related to immediate safety(swimming and alert) and comfort.These results oppose the compensatory foraging hypothesis in favor of increased security.The optimal diurnal energy expenditure model included river width and water depth,which had a positive relationship;an increase in either of these two factors resulted in an increase in energy expenditure.This study provides a better understanding of energy allocation strategies underlying the superficial time allocation of wintering waterbirds according to environmental conditions.Exploring these changes can help understand the maximum fitness of wintering waterbirds in response to nature and human influences.

An ethogram of Spot-billed Pelican(Pelecanus philippensis)

The Spot-billed Pelican(Pelecanus philippensis),a near threatened bird and one of eight pelican species in the world,can be found only in South and Southeast Asia over an area between 129000 and 181000 km 2 with strongholds in India,Sri Lanka,southern Cambodia and coastal areas of Sumatra.In India,it is presently distributed in southern and northeastern India with concentrations in Andhra Pradesh,Tamil Nadu,Karnataka and Assam states.An ethogram of the Spot-billed Pelican was presented and as many as 25 individual behaviors grouped under nine different categories were described:resting,alert,comfort/maintenance,locomotion,foraging,antagonistic,sexual,chick care and foraging,and vocalizations.Descriptions of behaviors of the Spot-billed Pelican in this paper would be immensely useful while preparing conservation and management plan for the species present both in the captive and wild condition.

Breeding biology of the Spot-billed Pelican(Pelecanus philippensis)in Karaivetti Bird Sanctuary,Tamil Nadu,India

The breeding biology of the Spot-billed Pelican(Pelecanus philippensis)was investigated from September 2007 to September 2010 in Karaivetti Lake,Tamil Nadu,India.The Spot-billed Pelican breeds between November and April at the Karaivetti Lake.It also breeds roughly during the same period at other breeding sites in Tamil Nadu,except for the Vedanthangal and Karikili bird sanctuaries,where pelicans arrives much earlier and their breeding activities start and end to some extent ahead of the other sites,i.e.,from September to March.In essence,the breeding season starts after the onset of the northeast monsoon in Tamil Nadu.A few days after their arrival,pelicans perform courtship display,form pairs,start nest construction and lay eggs.Courtship display is not as attractive and impressive as in other waterbirds.The clutch size varies from two to three eggs and the incubation period from 25 to 36 days.The fledging period varies from a minimum of 90 to a maximum of 102 days.The nest success rate of the Spot-billed Pelican at Karaivetti was 90.28% during the study period.

A review on the spot-billed pelican Pelecanus philippensis literature

Literature on spot-billed pelican has not been reviewed lately which could provide a critique of the emerging data. We have now chosen it as a key species through which we suggest a conservation action plan which will benefit several waterbird species. The information provided here is scholastic in nature and is meant to focus on aspects that require attention and help plan future work for applied conservation. All known information on this species is brought together in this review which will also provide an update of its biology. Notes on the breeding biology of the species first published in the Journal of the Bombay Natural History Society. So far, 380 works have appeared on the species; of these, 36 contain material reported in earlier works or appeared as papers subsequently. Most appeared as articles in journals, both national and regional, a few international journals, newsletters/bulletins （48.2%）, 4 dissertations, 76 reports and 6 popular science articles in magazines. This review on the species will provide an insight into different factors that can be weighed and combined while making a decision in investing resources in species conservation, i.e. importance of the species, level of threat and the time frame over which results are to be achieved.