Oil spills have often impacted large numbers of neritic and coastal seabirds, especially during the second half of the 20th century. In the Japan Sea, a large heavy-oil spill from the Russian tanker 'Nakhodka' in January 1997 oiled many seabirds. A total of 1, 315 dead and emaciated birds was counted on beaches, and among them, about 90 birds were released after cleaning and rehabilitation. Oiled bird rehabilitation has a long history in some countries, and the total number of birds that has been rehabititated and released throughout the world is at least in the low tens of thousands. From a conservation biological perspective, the need for an evaluation of the population-level contribution of released birds has been recognized since the 1980's. Very recent studies using recoveries of ringed diving birds (Uria aalge, Aechmophorus occidentalis/A. clarkii, Melanitta fusca, Melanitta perspicillata) in sub-high-latitude ocean regions indicate that post-release survival of rehabilitated birds is extremely poor (e. g., the survival rate of English Uria aalge in the first year after release was 0.6%, and the life expectancy of North American Uria aalge was 9.6 days). A radiotelemetry study of pelicans (Pelecanus occidentalis), which are marine surface feeders along coastal areas in middle latitudes, indicates that rehabilitated pelicans do not appear to breed, though survival is slightly longer than for diving birds. In contrast, studies on marked penguins (Spheniscus demersus) in middlelatitude waters off South Africa have shown that about half of rehabilitated penguins survived in the critical first year after release, and afterwards had a survival rate nearly as high as non-oiled penguins. For this species, listed as "near-threatened" in the IUCN Red Data Book, rehabititation has probably slowed to some extent the decrease of local populations or, in some cases, perhaps slowed the decrease of the population of this species as a whole. If rehabilitaion techniques can be improved for other diving birds (the most vulnerable to oil spills in northern neritic and coastal waters) and for surface feeders so that post-release survival is increased, oiled bird rehabilitation could become a valuable tool for the conservation of endangered or seriously threatened species when impacted by oil spills.
We reviewed effects of external oiling and ingestion of oil by birds. According to our classification system, neritic and coastal diving birds-of which there are six orders, six families, 26 genera, and about 100 species-represent the group of waterbirds most vulnerable to oil spills among the five groups. Oil adhering to plumage destroys waterproofing and greatly upsets thermal balance in these birds, most of which spend all day at sea. This may be the most acute effect of oil pollution on aquatic birds and is occasionally fatal to this group, especially while on the water or when exposed to low temperatures. Ingestion of oil reduces the excretion of salt through the salt gland, by interfering with absorption of hypertonic water by the intestinal mucosa. This results in water and osmotic imbalances. Detoxification by the liver of exogenous chemical substances in ingested oil causes excessive hormone metabolization, leading to deficiency of corticosterone hormones which function in osmoregulation and anti-stress mechanism. Hemosiderosis in the liver and spleen, decreased amounts of erythrocytes, and the presence of Heinz bodies in erythrocytes are seen in oiled birds both in the laboratory and in the field. Hypertrophy of the adrenals, atrophy of lymphatic organs, and elevation of corticosterone have often been reported, and evidence of stress-relating phenomena has also been documented on several occations. However, most studies have not been sufficient to reach any firm conclusions, due to difficulties in analysis. Oil contaminations of eggs or breeding adults conspicuously affect reproduction. Toxicity effects of petroleum on reproduction in seabirds include decreased eggshell thickness, reduced clutchsize, reduced chick survival, and even onset of malformations in developing embryos. Toxicity effects in the egg are dependent upon embryonal age, with sensitivity decreasing with age.
There are seventeen Crested Ibises (Nipponia nippon) in Beijing Zoo. Randomly amplified polymorphic DNA (RAPD) was first used to research intraspecific genetic relationships of eight ibises of them. Twenty arbitrary primers were used to amplify genomic DNA of eight Ibises and seventeen primers have distinct RAPD patterns in each amplification. One hundred and sixty-eight amplified fragments were generated by RAPD and one hundred and two fragments were shared by eight Ibises. Hierachical Cluster analysis of the RAPD data was used to calculate the similarity coefficients by spss/pc+ program. Based on the correlation similarity coefficient matrix, a dendrogram was constructed. The dendrogram indicates the genetic relationship of eight Crested Ibises. This study is the basis of constructing the genetic relationships dendrogram of all individuals, which is helpful in working out a better Crested Ibis conservation plan.
The change in distribution of Blakiston's Fish Owls Ketupa blakistoni was investigated by using primarily obtained specimens from museums and supplemented with information from the literature and Ainu legends. Sixtynine of 104 specimens found in Japan (including discarded) contain some information about their collection sites. Here I present historical evidence for the occurrence of fish owls in even the southern-most part of Hokkaido in the 19th century. However, habitat loss caused a reduction of population size and the owls disappeared from the southern and northern parts of Hokkaido in 1950's and from the Ishikari plain in the early 1980's. Their distribution in Hokkaido is now restricted to the eastern part of the island. Between 1954 and 1995 the causes of death were known for 31 fish owls. All deaths were caused by humans. Drowning in the fish-stocked ponds was the main cause (36.8%) followed by traffic accidents (21.1%) and electrocution (13.2%). In order to conserve the owl species, population changes should be monitored continuously and their habitats should be preserved and restored.