• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.1
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• pp.1-8
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• 1996

The objective of this study is to obtain the basic data for investigating the effects of organic reserves on winter survial or regrowth yield. Forage rape (Brussicu napus L.) was sown at 10 day> interval from Sep. I to Nov. 1. Field-grown palnts were sampled on the before wintering (Dec. 4) and on the wintering period (Jan. 16) to analyze the nitrogen and non-structural cahohydrate reserves. The rate of winter survival and regrowth yield were also measured in the spring of next year. On the before wintering, the dry matter yields from the plots sown on Sep. 1, Sep.11 and Sep. 21 were 860, 596 and 260 kg/lOa, respectively. No. harvest was canied out on the plots sown after Oct. 1 because the growth state was not enough to cut. Both of nitrogen and starch contents per plant significantly increased as the seeding date was later. On the wintering period, the contents of nitrogen reserves in roots were 176.8. 120.1, 71.7, 84.0, 72.1, 45.3 and 33.3 mg/plant, those of starch reserves were 199.0. 55.8, 21.8, 92.6, 86.5, 36.4 and 29.0 mglplant, resepctively, in the plots sown on Sep. 1, Sep. 11, Sep. 21, Oct. I, Oct. 11, Oct. 21 and Nov. 1. The rates of winter survival were 40, 36, 33, 85, 87, 59 and 49% and regrowth yields were 161, 86, 65, 520, 451, 121 and 33 kgD.M/lOa, respectively, in each plots. 'Ihese results clearly showed that seeding date has a close influence on the level of organic reserves and forage yield, and that the possibility of continuous utilization on the before and alter wintering is extremely limited by seeding date.

• Korean Journal of Veterinary Service
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• v.30 no.3
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• pp.467-472
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• 2007

Eurasian black vulture (Aegypius monachus) belongs to family Accipitridae and is a raptor preying small birds and mammals. It is a wintering bird residing from the mid of November to the late of March in Korea. Although Eurasian black vulture population wintering at Korea is gradually increased, the efficient rescue and treatment for injured Eurasian black vultures are still problematic, due to lack of basic data. Therefore, in this survey, to obtain basic resources for establishing more efficient rescue system, we surveyed the number of Eurasian black vultures wintering at Gangwon province, wintering ecology and injury state of Eurasian black vulture. Survey area was Togyo reservoir at Cheorwon, Seonan basin at Yangoo and Wolsong reservoir at Chuncheon from November 2004 to March 2005. From 12 rescued Eurasian black vultures, physical examination, total plasma protein (TPP) and packed cell volume (PCV) were measured. To survey injury state of Eurasian black vultures wintering at Gangwon province, we surveyed the cause, morbidity and mortality from 103 Eurasian black vultures, based on medical records from animal rescue teams. The number of eurasian black vultures were gradually increased from November, peaked at Feburary, then steeply decreased at March. Eurasian black vultures showed the most vigorous activity around 1 PM within a day. In physical examination, mean body weight was $9.6{\pm}1.22kg$, body length was $1130{\pm}45.4mm$. No statistically significant difference in body weight and length between male and female eurasian black vultures was observed. Mean PCV was $40.2{\pm}2.7%$, while mean TPP was $5.86{\pm}0.8mg/dl$. The most common cause of injury and mortality was intoxication, while that of morbidity was fatigue.

• Korean Journal of Environment and Ecology
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• v.34 no.3
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• pp.191-197
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• 2020

The purpose of this was to examine the differences of large whopper swan (Cygnus cygnus) in wintering habitat preference among bridge sections of the lower Nakdong River of the Nakdong River Estuary, the largest whopper swan's wintering habitat in Korea. This species is designated and protected as Natural Monument in Korea. The survey was conducted in six time-series during the 2018~2019 wintering season, and it found up to 500 whopper swans were wintering in the lower Nakdong River. For the survey, a seven sections were set up based on the bridges across the river. Whopper swans were rarely observed in five narrow sections where the distance between bridges was less than 2 km. The stable population of the whopper swan was observed only in two broader sections where the distance between bridges was is over 4 km. As these sections were relatively little affected by artificial interference, the distance from the mouth of the Nakdong River was not a factor. Securing a stable space is considered as one of the most important factors for wintering of whopper swans, which are an endangered species. The survey results indicate that the distance between bridges should be at least 4 km to secure the whopper swan's stable habitat. These results are expected to be a reference to the development or restoration of the river ecosystems, especially bridge construction.

• Korean Journal of Ecology and Environment
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• v.50 no.2
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• pp.266-274
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• 2017

We surveyed the habitat use and food materials of the endangered Swan Goose (Anser cygnoides) during the wintering period at the Seocheon tidal flat. The bird wintered about six months from October 2014 to early April 2015 at the flat. They showed a remarkable change in choosing their feeding habitat and prey. They stayed entirely at sedge grass patches on Songrim tidal flat during the early wintering period (October), while after November they gradually moved to Janggu bay and used rice paddy fields as well as sedge patches on the tidal flats as their feeding site. The dietary analysis showed the sedge grass (Bolboschoenus sp., Cyperaceae) was the main dietary source during the entire wintering period. Interestingly, the proportion of Cyperaceae on feces decreased slightly over wintering time, while the proportion of Fabaceae increased relatively since November. These results suggest that the Swan Geese switched their habitat and food sources in response to the change of food availability. The Seocheon tidal flat area is the important wintering site for Swan Geese and sedge grass patches in the area need to be managed as the main feeding area for the wintering Swan Geese.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.375-383
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• 2009

The aims of this study were wintering individuals, usage of foraging sites, potential food availability, daily activity and disturbance factors of White-naped Cranes Grus vipio on the wintering site, Han-river estuary, Goyang and Gimpo city, Korea. We want to provide basic data to conserve the cranes. Maxium population was identified 162 individuals at the middle of February in the river side and mud flat of this study area. Spring migration for breeding was started at the first week of March and finished for two weeks later. White-naped Cranes were used four feeding sites in winter; agricultural area in Hongdopyong, Yihwa-dong, Pyong-dong and Songpo-dong. Expected carrying capacity (ECC) was 334 days (121~909 days). White-naped Cranes departed from roosting site to feeding site at every morning for foraging. If they were disturbed by some factors at feeding sites, they moved to mud flat in the Han river to forage and take a rest. Daily activity was consisted of six category; feeding, alert, locomotion, preening, comfort, social and other behaviors. Feeding was the highest portion among behaviors in the wintering area. Feeding, alert, locomotion and preening in daily activities significantly differed among feeding sites. We watched total 348 times of disturbances in the wintering sites. Artificial disturbances were vehicles, humans, bicycles and motorcycles. Natural disturbances were noises, animals and others. Disturbances in all wintering sites were highest in Yihwa-dong (134 times) and followed by Hongdopyong (109 times), Songpo-dong (64 times) and then Pyong-dong (44 times). And artificial disturbances (228 times) were more than natural disturbances (120 times). Especially, vehicle was one of the most checked factor in the wintering area.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.354-361
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• 2012

This study was conducted to evaluate on the freezing tolerance of introduced blueberry cultivars in Korea and to investigate availability of portable timber moisture meter for simple and rapid diagnosis of blueberry-shoot damage by freezing during wintering. Frost tolerance of blueberry cultivars showed big difference that rates of blueberry-shoot death were widely distributed from about 0% to 100% after wintering. Optical density in TTC reduction of blueberry twig treated low temperature was low in order of $-40^{\circ}C$ < $-21^{\circ}C$ < $4^{\circ}C$. Hardiness evaluation of visible injury in the cross-sectional surface color did not agree with that of rates of blueberry-shoot death during wintering. Lowest water content of blueberry stem measured by timber moisture tester during wintering was about 15%. During wintering, water contents of blueberry stems were higher at lower part of tree, but were low at end part of stems, and then when the blueberry grew again for spring, the water content gradually increased to 20~40%. Water content of blueberry stem with freezing injury during wintering decreased to under 5% by desiccation. Therefore it is assummed that the moisture content of blueberry stem injured by freezing during wintering was about under 14%, and it is expected that portable timber moisture meter could be available for rapid diagnosis of blueberry freezing injury in field.

• Korean Journal of Environment and Ecology
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• v.23 no.3
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• pp.250-257
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• 2009

This study was conducted to investigate the habitat use of White-naped Cranes Grus vipio in Han river estuary during the wintering period from 2006 to 2008 (October$\sim$March). The average numbers of wintering White-naped Cranes were 106.6$\pm$21.7 (Mean$\pm$SD) individuals, and the highest number of 140 individuals were recorded in the early January, 2008. The wintering habitat use of White-naped Cranes between rice field and mudflat was not significantly different (Mann-Whitney test. p=0.40) during the wintering period. However, White-naped Cranes spent more time on the rice field in the early winter (p<0.01), and on the mudflat in the late winter(p<0.01). There was not a difference of the habitat use rate on middle winter. White-naped cranes used four different sites of rice field: Hongdopyoung, Pyoungdong, Ihwadong and Janghang rice fields. Among them, Hongdopyoung was the main foraging site. There was significant differences of habitat use ratio in the early and mid winter ((Kruskal-wallis test. p<0.01). White-naped Cranes used mudflat area from Gimpo Daegyo to Nusanri of Han river estuary. Especially, they preferred four sites from Gimpo Daegyo to Ilsan Daegyo more than the other sites. Habitat use rate of mud flats were significantly different among each site during the wintering period (Kruskal-wallis test. p<0.01)

• Journal of Korean Society on Water Environment
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• v.26 no.2
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• pp.311-316
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• 2010

We estimated the nitrogen and phosphorus loads of wintering waterfowl feces in Lake Paldang. The average number of individual birds that belonged to Anatidae species was 2,852.5 from 2005 to 2008 in Lake Paldang. The number of Anatidae reached 97.4% of the total number of individual birds. For evaluating the loading amounts of N and P by waterfowl to Lake Paldang, the feces dry weight (g/day) of each Anatidae species was estimated by multiplying the body weight of the each bird by 2.25% and assumed that N and P in feces contain 1.46% and 0.33%, respectively. We assigned probability 1/3 to the nutrient decomposition of the bird feces in water. The nitrogen loading by wintering waterfowl feces was 0.06 ton/year and the phosphorus loading was 0.001 ton/year. These amounts were 0.0002% of all N loadings and 0.0001% of all P loadings. Therefore the wintering waterfowl might have little impact on the water quality in terms of eutrophication in Lake Paldang.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.291-299
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• 2012

This experiment was conducted to investigate the effects of the addition of wintering waterfowl's feces prior to planting rice on nutrient dynamics, rice growth, and decomposition of rice straws in a controlled mesocosm. Waterfowl's feces and rice straws were placed on paddy soils in a mesocosm and the water level maintained at 5 cm. The amounts of supplied feces were 0 (control), 222, and 444 g/$m^2$. While the addition of feces showed no immediate effects, nutrients in the surface water increased in the month following treatment. Nutrients increased to a greater degree in the treatments with more feces added. Simultaneously, the decomposition of rice straws was promoted, indicating that more nutrients would be made available over time. The rice showed high productivity in the period during which nutrient level was increased, when rice needs more nutrients for the tillering stage. Therefore, the wintering waterfowl's feces could be associated with increased productivity during the growing season of rice through promoting nutrient supply and rapid decomposition of rice residue.

• Animal cells and systems
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• v.1 no.4
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• pp.571-576
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• 1997

The playas of the Southern High Plains (SHP) of Texas, USA are an important habitat for over one million wintering waterfowl. However, the recent trend toward the modification of playas for agricultural use is threatening winter habitat of waterfowl in this region. Diurnal activity budgets of wintering mallards (Anas platyrhynchos) were conducted from 1 October to 31 March, 1983-1984, and 1984-1985) at three habitat types; steep-sided pits, terraced pits, and open lakes. All seven activity patterns (feeding, locomotion, resting, comfort, courtship, alert, and agonistic) were different (P<0.05) among the three habitat types for wintering mallards on the SHP of Texas. Terraced pits supported more feeding activity (27.8%) (P<0.001) than steep-sided pits (11.2%) or open lakes (2.6%) due to their abundance of natural seeds and aquatic invertebrates. Hens (17.5%) fed more than drakes (11.7%) (P<0.05). Locomotion (32.2%) and alert (2.8%) behavior across the three habitat types showed the highest level during the early morning (6:00-9:00 AM). Paired mallards rested more (37.9%) than unpaired mallards (25.8%) (P<0.05). Agonistic activity was highest (2.4%) in terraced pits throughout the season.