Egretta ibis
Rare visitor: recorded only occasionally in this country
Cattle Egret (Egretta ibis) is a compact white heron represented in the catalogue under an alternative scientific combination, with buff breeding plumes and a short stout bill. Body shape, bill structure, plumage pattern and voice provide the strongest field characters. Age, sex and season may alter its appearance, so identification should combine several features and careful direct field comparisons with similar species in the same habitat (Wikipedia, general species account).
It feeds mainly on land around livestock and agricultural machinery, seizing insects and small vertebrates flushed from grass, and gathers colonially to roost and breed. Its movements and social behaviour vary through the year, with breeding birds generally more dispersed and non-breeding birds gathering where food is concentrated. Japanese records place it within the country's documented avifauna as a resident, migrant or visitor (Wikipedia, general species account; Wildlife of Japan occurrence records).