During the autumn migration of many waterfowls, body mass is lowest upon arrival at the wintering area and gradually increases during the winter. Consequently, body mass is highest before the spring migration. We studied the
pattern of body mass changes in the Black-Headed Gull (Larus ridibundus) from December 2010 to December 2016 in the Shinhama area of Chiba, Japan. Based on 327 captured animals, body mass increased during the
wintering period, but tended to decrease before migration. In 2014–2016, a muscle mass reduction in females was observed, explaining the change in body mass. However, the observed weight loss may be caused by many factors, which
may be related to the migratory ecology of the regional population.
鳥類の性別は,野外での生態・分布調査のみならず(成田 1999) ,希少種の飼育下繁殖(Hayama et minami-cho, Musashino-shi, Tokyo 180-8602, Japan. 加藤卓也 ₁ ₁ 〒180-8602 東京都武蔵野市境南町1-7-1 日本獣医生命科学大学 疾病予防獣医学分野 野生動物学部門野生動 物学研究室 Takuya Kato ₁ ₁ Center for Wildlife Conser vation and Management, Nippon veterinar y and life science university. 1-7-1 Sakaiminami-cho, Musashino-shi, Tokyo 180-8602, Japan.羽山伸一 ₁ ₁ 〒180-8602 東京都武蔵野市境南町1-7-1 日本獣医生命科学大学 疾病予防獣医学分野 野生動物学部門野生動 物学研究室 Shin-ichi Hayama ₁ ₁ Center for Wildlife Conser vation and Management, Nippon veterinar y and life science university. 1-7-1 Sakaiminami-cho, Musashino-shi, Tokyo 180-8602, Japan.
ABSTRACTSex identification in Japanese birds using droppings as a source of DNA Nana USHINE * , Takuya KATO and Shin-ichi HAYAMA In order to establish the minimum adverse effect of the sex identification method in birds, the droppings of 11 orders of 42 species of Japanese birds were collected for DNA analysis. The chromosomes used for sex identification were the protein-encoding spindlin gene (SPIN), presumptive pseudogene (EE0.6), and chromo helicase DNA-binding gene (CHD). The CHD gene was reported to be conclusive in gender discrimination and was amplified using the polymerase chain reaction (PCR) by changing the primer and temperature conditions for each species. As a result, although sexing in some species and samples was not confirmed, the amplification of specific gene regions for sexing was confirmed in 10 orders of 36 species of birds. In species and samples where amplification was not confirmed, selection of adequate extraction procedures for sex identification using bird droppings was needed. Nine species that confirmed the amplification of regions for sexing, from the number of tested samples and the population in which amplification was confirmed, determined that this method was practical for sex identification. This method can also be used for sex identification using the droppings from chicks. Thus, this method not only reduced the burden on the birds compared to conventional methods but also suggested that the sexing condition was wide.
In order to elucidate the relationship between migration period and immunity related to susceptibility, we conducted research on Black-headed gulls
(
Chroicocephalus ridibundus
). We captured 260 gulls and collected their peripheral blood. Their leukocyte (WBC) count, percentages of
heterophils (Het) and lymphocytes (Lym), heterophil and lymphocyte ratio (H/L ratio), and CD4 and CD8α expression levels (CD4 and CD8α, respectively) were
quantitatively analyzed over three migration periods (Autumn migration, Wintering, Spring migration). In Adult gulls, WBC counts and CD4 levels significantly
increased. Moreover, the Het and H/L ratio decreased from the Autumn migration to Wintering. Conversely, only WBC counts and CD4 levels measurements
significantly decreased from Wintering to Spring migration (
P
<0.05). The tested parameters of the Tokyo-bay population show a greater
significant difference than the measurements of immunity of the Mikawa-bay population. This study suggests that the migratory period has a negative effect on an
aspect of the immune system. Including the period-difference in the immune systems in the local population, it is necessary to investigate the relationship
between the ecology of migratory birds and their immunity.
Few studies have evaluated immunosuppression due to lead accumulation below the overt
toxicity threshold. If low levels of lead accumulation cause immunosuppression in birds,
those birds could become more susceptible to pathogens. We aimed to determine if low
levels of lead accumulation lead to immunosuppression in Black-headed gulls
(
Chroicocephalus ridibundus
). Gulls were captured in Tokyo-bay and
Mikawa-bay from January to April 2019. Their blood samples were analyzed for eight items.
The data were analyzed to evaluate the correlation between lead concentrations and the
variables from each bay. Lead was positively correlated with the percentage of heterophils
and heterophil and lymphocyte ratio and negatively with lymphocytes. Thus, low lead
accumulation levels may induce changes in percentage of the heterophils and
lymphocyte.
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