Age-related Difference in Bill Length of the Grey Heron Ardea cinerea jouyi and Estimation of Prey Size Using Bill Length

Maékawa, Shohei; Sawara, Yuji

doi:10.3838/jjo.45.183

Cited by 1 publication

(1 citation statement)

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“…Captured fish size was measured at 3 cm intervals by estimating the size relative to bill length (exposed culmen, ca. 12 cm) of grey herons to estimate biomass intake rate (Bayer 1985, Maekawa andSawara 1996). A volume index was used to estimate relative biomass of consumed fish and was calculated by squaring body length (Sato and Maruyama 1996).…”

Section: Age Effectmentioning

confidence: 99%

Factors affecting feeding activity of grey herons in a reservoir during the breeding season

Choi¹,

Yoo²

2011

J. Ecol. Environ.

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To examine factors affecting feeding efficiency of grey herons (Ardea cinerea), the foraging behavior was studied at a reservoir in Asan city, Chungcheongnam-do, South Korea during the breeding seasons (from April to July) of 2006 and 2007. Four factors (age of foraging birds, time of day, breeding stage, and microhabitat type) were analyzed. Adults were more efficient foragers than recently fledged juveniles, and they had a higher success rate than juveniles. About half of the adults caught large prey, whereas most juveniles caught only small prey. Adult grey herons had different feeding efficiency according to the breeding stage. Pecking and capture rates were high during the late period (fledging stage), and biomass intake rates were high during the early (incubating stage) and late periods. However, time of day had no significant effect on foraging activity of adult grey herons. Feeding activities of adult grey herons also showed significant variation among microhabitat types. Pecking and capture rates were higher in the submerged plants area, but capture success rate and biomass intake rate were not different according to microhabitat type.

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Section: Age Effectmentioning

confidence: 99%