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Table 1 Comparing daily energy intake of Swan Goose feeding on the Vallisneria natans tuber buried at different sediment layers at Shengjin Lake, China

From: Wintering Swan Geese maximize energy intake through substrate foraging depth when feeding on buried Vallisneria natans tubers

Sediment layers

Mean tuber dry weight (g)

a

Total daily feeding time (min)

b

Number of tubers

Tuber intake rate (tubers per min)

c

Tubers consumed per day

d = b × c

Total tuber dry weight consumed per day

e = a × d

Tuber energy content (dry weight)

(kJ per g)

f

Total daily intake (kJ per day)

g = e × f

Layer 1 (1–10 cm)

0.15 ± 0.018 (86)

442.2

87

1.40

619.08

92.86

14.77 ± 0.14 (4)

1371.57

Layer 2 (11–20 cm)

0.26 ± 0.029 (97)

104

1.67

738.47

192.00

2835.89

Layer 3 (21–30 cm)

0.35 ± 0.100 (17)

18

0.29

128.24

44.88

662.93

  1. Mean tuber dry weight of each layer was calculated based on tuber dry weight. The total daily feeding time and tuber energy content were obtained from Fox et al. (2011), whereas the tuber intake rate was calculated from Fox et al. (2011) using the percentage of tubers at each layer (including number of burned tubers). Values indicate means ± 95% confidence intervals. Numbers in parentheses indicate sample size
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Avian Research

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