Effectiveness of the species separation criteria was examined by observing 33 Marsh Tits Poecile palustris and 24 Willow Tits P. montanus from Hokkaido, Japan. As in Europe, the difference in bill marks was useful in Hokkaido, except when specimens still had their juvenile plumage. In fall-to-winter, a pale brown stain on the cheek area was also a useful criterion to identify Marsh Tits, but the “bib” was not useful. Reliability of all criteria based on feather color or length was low or none during breeding season and juvenile plumage. When mention about color of upper parts of both species, it should be necessary to consider about changes of feather color by wear and breach. Changes in feather color by wear and breach should be taken into consideration when color of upper parts are mentioned.

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We compared the leg structure of 174 Marsh Tits Poecile palustris and 95 Willow Tits P. montanus from Hokkaido, Japan. Overall, the Willow Tit had a significantly longer hind claw, middle claw, and tarsus than the Marsh Tit. In Marsh Tits, 99% of the hind claws were 7.1 mm long or less, and tended to have a strong curvature with a blunt tip. But in Willow Tits, 98% of the hind claws were 7.2 mm long or more, and tended to have a weak curvature with a sharp tip. Therefore, these hind claw characteristics are very effective as criteria for species separation, regardless of age or season.

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Body weight, maximum wing length, and tail length of Meadow BuntingsEmberiza cioides, Great Tits Parus minor, Pale Thrushes Turdus pallidus, and Japanese Bush Warblers Cettia diphone were measured from May 1993 to June 2017 at a coastal windbreak forest along Kanazawa, in Ishikawa prefecture, Japan. Statistically significant values were found for three species. Adult male Meadow Buntings had greater maximum wing and tail lengths than adult females during the spring season, and juvenile males were heavier than adult males in spring season. Adult male Great Tits had greater maximum wing and tail lengths than adult females in the spring season; in autumn season, juvenile males had greater maximum wing and tail lengths and heavier bodies than juvenile females; and adult males in autumn had heavier bodies than adult males in spring. Male Japanese Bush Warblers had greater maximum wing and tail lengths and heavier bodies than females in both adult/spring season and juvenile/autumn season comparisons. When examining body weight values for all individuals of each species, minimum and maximum values were 84.4% and 119.0% of mean value in male Meadow Buntings and were 78.9% and 118.8% of mean value in male Great Tits; and no individual had increased body weight rapidly and widely even during the migratory period.

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On 14 Nov. 2012, the first Manchurian Reed Warbler Acrocephalus tangorum ever recorded in Japan was ringed and released at Nobeoka, Miyazaki prefecture, in Japan. This specimen had a darkish yellow-brown upper part; whitish throat and belly; more pale yellow-brown sides, center of breast, and under tail-coverts; an obvious supercilium and its dark colored upper edge near the side of the head; and dark center with pale edge of tertials. The longest primary feather was the seventh primary (P7), its upper mandible had a black color and its lower mandible had a pink color with pale blackish tip. These characteristics indicate it was a Manchurian Reed Warbler.

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The color and shape of remiges of first-winter plumage of the Ruddy-breasted CrakePorzana fusca observed in Wakayama Prefecture, Japan in October 2016 were reported in this study. The color of remiges of first-winter plumage was darker than that of body feathers and wing-coverts. The shape of the end of the outer primaries was narrow and sharp. These features are the same as those of remiges of juvenile plumage, and support the findings that P. fusca does not molt remiges and wing-coverts in post-juvenile molt. Therefore, color comparison between remiges and wing-coverts might be a useful tool for estimating the age of P. fusca.

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