Foraging behavior of the Greater White-fronted Goose (Anser albifrons) wintering at Shengjin Lake: diet shifts and habitat use

Abstract

Background: The habitat use and foraging behaviors of waterbirds are closely related to the distribution and abundance of their food resources. Reductions in food supply can cause waterbirds to shift their habitats and adjust their foraging behaviors to meet their nutritional requirements and increase fitness. Seasonal withdraw of the water levels in the river-connected lakes in the middle and lower Yangtze River floodplain provides abundant food resources for the wintering Greater White-fronted Goose (Anser albifrons). Sedge (Carex) meadows are critical foraging habitats for herbivorous waterbirds in the hydro-fluctuation belt, which changes with hydrological conditions and climate. This study aimed to examine the behavioral responses of the Greater White-fronted Goose to temporal-spatial changes of food availability in the Sedge meadows. Methods: Fields surveys were carried out at Shengjin Lake from November 2017 to April 2018. According to the phenology of Shengjin Lake, we divided the wintering season into three periods. The food density, minimum temperature, food items, grass height, and number of foraging geese were surveyed, and samples of the foraging behavior were collected. We analyzed the relationship of the foraging behavior and habitat use relative to the food resources, using correlation and linear regression analyses. Results: Along with the temporal-spatial variation and exploitation of food resources, the food abundance and items varied widely among the foraging sites. Over the whole wintering period, the foraging habitat with the highest utilization rate was the meadows, followed by the paddy fields, and then mudflats. Furthermore, the utilization of the meadows showed a bimodal distribution trend, while the paddy fields showed a unimodal trend, and a decreasing trend was seen in the mudflats over the whole wintering period. The results of the generalized linear model showed that the foraging rate was related to the food density and grass height, with a linearly increasing trend during the winter. Conclusions: With the change of food resources in the three habitats, the habitats used by the Greater White-fronted Geese shifted from meadows in the hydro-fluctuation belt to the paddy fields, and then back to the meadows. The time budget for foraging activities increased correspondingly, and there was an increase in the foraging rate to compensate for food shortages.

Effect of conspecific neighbors on the foraging activity levels of the wintering Oriental Storks (Ciconia boyciana): Benefits of social information

“…During the whole observation, if a stork caught a fish with its bill and then swallowed it, this meant they had foraging success. Through field observations and relevant literature, we used three variables to characterize foraging activity levels: foraging rate (the total number of pecks within a 1‐min period), foraging effort (the ratio of the total amount of time spent searching for and processing food and the activity time budget), and foraging success rate (the percentage of times that foraging was successful as a percentage of the total number of foraging behaviors; Amano, Ushiyama, Fujita, & Higuchi, 2006; Fan, Zhou, Cheng, Song, & Xu, 2020; Kuwae, Miyoshi, Sassa, & Watabe, 2010; Wan, Zhou, & Song, 2016). We defined the foraging activity intensity of neighbors as (a) the ratio of neighbors foraging, NFR = the number of neighbors foraging/the total number of neighbors × 100% and (b) foraging activity levels of neighbors.…”

Spatiotemporal Variation of Siberian Crane Habitats and the Response to Water Level in Poyang Lake Wetland, China

“…The aggregation structure of the non-habitat areas of the Siberian cranes was partly strengthened, whereas the variety of the "Lake Enclosed in Autumn" regions was clearly enhanced. Thus, under extremely low to average water levels, the stability and variety of the crane habitats simultaneously decreased as water level increased, and the aggregation structure of the crane habitats was weakened, which is likely related to the habitat landscape and food resource changes induced by changing water levels [16,21,59].…”

“…Many previous studies have explored the ecological habits and habitat selection of migratory birds, such as suitable habitats [18][19][20], foraging behaviors [21][22][23][24], and overnight accommodation [25]. In terms of the environmental health assessment of migratory bird habitats, previous approaches have investigated spatiotemporal variations of habitats [26][27][28][29], amount characteristics and migration patterns [30,31], vegetation structure [32][33][34], biodiversity [35][36][37], etc.…”

Spring diet and energy intake of whooper swans (Cygnus cygnus) at the Yellow River National Wetland in Baotou, China

“…Wetlands are important ecological systems that aid in preventing floods and droughts, purifying water quality, and regulating climate [ 1 ]. Waterbirds typically depend on wetlands for their abundant food availability and habitat suitability [ 2 ]. Abundance and distribution of waterbirds can reflect the structure and functions of wetlands, making them important bio-indicators for wetland health [ 3 ].…”