Filarial nematodes belonging to the superorders Diplotriaenoidea and Aproctoidea from wild and captive birds in Japan

Eight species of filarial nematodes of the superorders Diplotriaenoidea and Aproctoidea were collected from the lung, air sac, abdominal cavity, and subdermal layer of the neck of wild and captive birds in Japan. The species of the filarial nematodes were identified as Diplotriaena bargusinica, D. henryi, Serratospiculum kwangsiensis, S. tendo, Hamatospiculum accipitris, H. cylindricum, H. quadridens, and Lissonema noctuae based on morphometry and pathogenicity. D. henryi from Poecile varius, H. accipitris from Accipiter gentilis, H. cylindricum from Lanius bucephalus and H. quadridens from Otus flammeolus represent the first host records worldwide. Moreover, D. henryi, S. kwangsiensis, H. cylindricum, and L. noctuae were the first geographical records from Japan

Nest and roost characteristics of the Ruddy-breasted Crake Porzana fusca on Minami-daito Island

We found five Ruddy-breasted Crake Porzana fusca nests in a swamp among emergent vegetation, and one in a dry sugarcane field more than 500 m (radius) from any swamp or pond, on Minami-daito Island. Nests were saucer-shaped. All of the nests in the swamp fledged chicks. It is assumed that nesting in such habitat renders nests safe from ground predators such as introduced weasels and feral cats. Roosts were similar in structure to nests, but lacked lining. It is inferred from one observation that males and females roost together at night before the egg-laying period

Sex and age-class differences in feather mite loads in white wagtails Motacilla alba lugens suggest self-regulation of feather mites by birds

In order to investigate the relationship between feather mites and their hosts taking into account host ecology I examined relationships among feather mite load, and sex, age, wing length and body-condition in the white wagtail Motacilla alba lugens. I captured 288 wagtails in January (the first period) 2002 at a communal roost in Osaka, central Japan. All the wagtails were ringed individually, aged as yearlings (first-winter) or adults (older) and sexed. I measured wing length, tarsus length and body mass, calculated a body condition index (BCI) and determined the feather mite loads (FML) of each individual by visual examination of the flight feathers of one wing, giving a score using the range 0-5. I recaptured 121 wagtails after an average of 45 days (the second period), and redetermined their FML. FML was not correlated with wing length or body-condition. Yearlings had higher FML than adults in both periods. Males had greater FML than females in the second period. No significant differences in FML between the first and second periods were detected among yearling females, or adult males, but adult females had significantly lower FML and yearling males had significantly higher FML than the other age-sex classes in the second period. The sexual difference was caused by the lower FML of adult females and the higher FML of yearling males. The BCI of yearling males was the lowest among the four combinations of sex and age-class. I conclude that wagtails may be able to prevent overpopulation of feather mites on their own plumage. The ability to control mite populations may be related to the condition of the host

Distinctive features of the skull of the Ryukyu Scops Owl from Minami-daito Island, revealed by computed tomography scanning

Morphological differentiation of island-dwelling organisms provides model systems for studying evolution. Computed tomography (CT) scanning is an entirely non-destructive technique that provides detailed three-dimensional (3D) images of physical structures. Geometric morphometrics has been increasingly used in avian morphology studies by analyzing 3D data obtained from CT scans. We used geometric morphometrics to evaluate the morphological details of the skulls of three, genetically distinct, island populations of the Ryukyu Scops Owl Otus elegans: O. e. elegans from the northern part of the Ryukyu Archipelago, O. e. elegans from the southern part of the Ryukyu Archipelago, and O. e. interpositus from Minami-daito Island. Skulls were scanned using an X-ray CT system and the digitized 3D coordinates of 16 landmarks for each skull were analyzed in order to describe geometric morphometric features. O. e. interpositus was found to have a significantly smaller skull than either population of O. e. elegans. From principle component analysis of shape variation, we also found that the skull shape of O. e. interpositus differed significantly from both the northern and southern groups of O. e. elegans. This difference was in terms of PC1, which mainly represented relative anteroposterior length, and angle of the orbit. We inferred that the small skull of O. e. interpositus is partly a consequence of the particular founders of the population, or evolutionary selection that has taken place on Minami-daito Island and that the distinctive shape of the skull of O. e. interpositus is partly a consequence of adaptations for foraging efficiency, or of morphological integration