# Impacts of Food‐Based Flock Size on Foraging Patterns, Activity Time Budget and Foraging Efficiency: Flexible Behavioral Responses of the Wintering Oriental Storks (Ciconia boyciana) to Changes in Aquaculture at Shengjin Lake, China

## TL;DR

This study shows how wintering Oriental Storks adapt their foraging behavior in response to changes in aquaculture practices at Shengjin Lake, China.

## Contribution

The paper reveals how food availability and habitat fragmentation influence foraging strategies and activity budgets of storks in aquaculture settings.

## Key findings

- Storks in the pen culture period had a reduced range and population size due to habitat fragmentation.
- Foraging and locomotion time increased in the pen culture period compared to the non-pen culture period.
- Habitat connectivity after pen removal led to more flexible foraging patterns in storks.

## Abstract

Food resources, as key limiting factors for wintering waterbirds, influence their habitat selection patterns and foraging behaviors. Meanwhile, seasonal fluctuations in water levels and human exploitation of lake wetlands both affect the availability of food. Therefore, knowledge of the spatio‐temporal dynamics of habitat utilization and adaptive behavior strategies can provide insights into how animals adapt to habitat changes in wetlands and has important conservation implications. In this study, we examined the effect of dynamic food resource supply on the spatial patterns, activity budget, and foraging strategy of Oriental Storks (
Ciconia boyciana
) at Shengjin Lake in China during a period where extensive fishing nets were present limiting the movement and dispersal of waterbirds (“pen culture period, PP” in 2017 winter) and a period after the removal of these pens during wetland restoration (“non‐pen culture period, NPP” in 2018 winter). In comparing with the wintering storks in NPP, we demonstrated an overall loss of range and a significant reduction in population size in PP, which were probably due to habitat alteration and fragmentation triggered by pen culture. We reported that a higher overall time budget in foraging and locomotion and a comparatively lower in other behaviors with storks in PP. Net pens resulted in limited activity areas of the storks and a reduction in food availability due to habitat alteration and fragmentation, thus resulting in a more flexible and radical trend in the foraging patterns of the wintering storks was triggered by the combined effects of the net pens removal and habitat connectivity in NPP. Pen culture had resulted in a more conservative foraging strategy and a homogenization of behavioral composition for wintering storks at the lake. Our study highlighted the behavior‐based results may provide key information to conceive management and conservation plans for wintering waterbirds.

This paper provided a small‐scale but important case study, adding to our knowledge of Oriental Storks in aquaculture fisheries in the middle and lower Yangtze River floodplain, and analyzed the impacts of food‐underpinned flock size on activity time budget adjustments and foraging strategy adaptation of the wintering Oriental Storks. The results have implications for the conservation management of other endangered waterbirds facing pressures from culture‐based fisheries.