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Recent data about the fish consumption of great Cormorant in the area of Hortobágy Fish Farm Co
75-80Views:196The cormorant (Phalacrocorax carbo) is a bird species that nests sporadically but in colonies, besides larger fishponds and rivers in Hungary. The number of its individuals has been increasing during the last two decades. The species eats solely fish, therefore it can cause serious depredation of the fish stocks in fishponds of intensive system and after the freezing of the ponds, in larger rivers, which are not yet frozen. The aim of our research was to reveal the damages the birds can cause on the studied areas and the extent of the losses the Hortobágy Fish Farm Co. has to realize.
Our studies were carried out between April 2012 and November 2014. During cleaning, the investigation of the craw contents of the birds and their biometric studies were conducted. The results revealed the diverse food base of the species. In the samples, we have determined 379 fish individuals; in 368 cases, the exact fish species were determined, too. Significant differences were found between the consumed fish species rations of the units (P=0.05% beside). We have also found significant difference in the fish consumptions of adult males and females.
Under the ever harder fish production conditions, the presence and thus the permanent predation of the birds affect the fishermen. In favour of maintaining ecological balance as well as to hold the income of the fish farmers, elaboration of adequate protective and preventive methods will be needed in near future.
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Population date of Great Cormorant at the area of the Hortobágy Fish Farm Co.
51-54Views:223Hungary’s great cormorant stock did not use to be a considerable one before the 1980s. After that, their number has been rising significantly. The size of the stock now is rather stagnating or slightly growing. The presence of cormorants has been significant around ponds of the Hortobágy Fish Farm in the past few years. Due to considerable fish consumption of cormorants it is essential to know which and what kinds of units of the ponds (spawning, supply, and market) are preferred by the birds in order to see to adequate protection. The aim of our research was to discover any differences in the number of cormorants present at particular units of the fishpond system and certain ponds of equal kinds within them.
Our observations were in line with the methods used in ornithological researches. The experiment took place between April and October 2012 on a monthly basis. According to the results we found relevant differences in the number of cormorants based on the seasons and months as well. This fact was supported by statistical data. During the autumn and winter birds prefer supply and market purpose ponds while their presence here is vanishing during the summer. Relevant presence of cormorants around the area of the Old Fishponds (70 to 200 specimens) might be due to lack of disturbance and large sizes of the ponds.
Our research has great scientific relevance since it is vital to be aware of the preferred periods and areas in order to maintain effective protection; this way alerting activities can be applied in a more harmonized way. By keeping our research up as a monitoring activity, we will be able to receive more precise data later on.
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Fish consumption of the great cormorant in the area of Hortobágy Fish Farm
81-84Views:125The cormorant (Phalacrocorax carbo) is a bird species that nests sporadically but in colonies, besides larger fishponds and rivers in Hungary. The number of its individuals has been increasing during the last two decades. The species eats solely fish, therefore it can cause serious depredation of the fish stocks in fishponds of intensive system and after the freezing of the ponds, in larger rivers, which are not yet frozen. The aim of our research is to reveal the damages the birds can cause on the studied areas and the extent of the losses the Hortobágy Fish Farm Co. has to realize.
Our studies were carried out between April 2012 and November 2013. During cleaning, the investigation of the crop contents of the birds and their biometric studies were conducted. The results revealed the diverse nutrition base of the species. In the samples, we have determined 300 identified fish individuals; in 289 cases, the exact fish species were determined, too. Although statistical differences were found between the given pond unit and the consuming of the corresponding fish species (P=0.05% beside), this cannot be considered as absolutely certain.
Our investigation is of considerable significance in terms of nature preservation and not least, it has substantial financial concerns too. Under the ever harder fish production conditions, the presence and thus the permanent nutrition of the bird affect the fishermen. In favour of the maintaining of the natural ecological balance and the income of the fishers, the elaboration of adequate protective and efficient preventive processes will be necessary in the near future.
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The Number and Species of Migrating Wild Geese in Hortobágy
22-25Views:94This paper presents the total number and annual distribution of wild geese population on Puszta Hortobágy. Two migrating goose species, White-fronted Goose (Anser albifrons) and Bean Goose (Anser fabalis) contribute most to the total number of geese population. Feeding place selection of goose depend on the season. In autumn and winter, croplands largely provided food for geese. Due to selections among fields and parts of the field, sometimes relatively high grazing pressure for the whole area may be severely multiplied in some cases resulting potentially 100% shoot defoliation on the frequented sites of a wheat field.
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The Role of Grasslands in the Diet of Geese
19-21Views:84A feeding trial was conducted with 4 weeks old growing geese. Feeding treatments were different proportion of chopped grass and grain pellets. Daily DM intake, weekly live weight gains and final live weight was measured. It is concluded that 25% of chopped grass in the diet has similar result as only grain pellet diet. This is good for the economy of goose production.
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Nest-site preference of Hooded Crow (Corvus cornix L.) in Debrecen, Hungary
13-17Views:117In the past decade, the population of the Hooded Crow has shown significant growth in Debrecen, Hungary. The aim of this study was to become acquainted with the nest-site selection behavior of Hooded Crows in urban spaces. While our research revealed that the Hooded Crow is not particular when it comes to selecting among tree species for nesting, we did notice differences regarding nesting height. Hooded Crows living in the city build their nests higher up than those living outside Debrecen’s city limits. We also discovered a slight, insignificant difference between nesting heights and tree species, which is probably due to the different characteristics of the given tree species. As for nesting heights, we found that in typical urban habitats there were no relevant differences. However, when we compared these habitats in pairs, it came to light that nesting heights -when comparing solitary trees - wood segments and tree rows - wooded segments- did show significant differences, which can be explained by the various conditions provided by the habitats mentioned.
In summary, the following results emerged from our research:
1. The Hooded Crow prefers approximately the same nesting heights in all kinds of habitats, urban environment and tree species.
2. The nesting height does not significantly depend on the habitat itself or on the tree species. -
Goose Production Responses to Grass-Based Diets
26-28Views:100A feeding trial with 4 week-old goslings was conducted in 2003 using different proportions of chopped grass and grain pellets in the diet. Proportions of chopped grass and grain pellets in diets for Treatments 1, 2, 3 and 4 were 25:75; 50:50; 75:25 and 0:100, respectively. Weekly and final live weights of geese and the feather quality were measured. Treatments with higher grain contents produced higher live weights, and better feather quality.
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Nest-site selection of Hooded Crow (Corvus cornix) in urban environment
35-39Views:156In the past decade Hooded Crows showed a significant growth in Debrecen. The aim of this study was to become acquainted with Hooded Crows nest-site selection in urban circumstances. The research revealed that Hooded Crows are not choosy when it comes to selecting the species of the trees, but we noticed differences regarding nesting height - Hooded Crows living in the city build their nests in higher regions than those living in places outside Debrecen. We discovered a significant difference between nesting heights and the tree species, which is probably due to the different characteristics shown by the given tree species. As for nesting heights, we found that in typical urban habitats there were no relevant differences shown. Samet the situation, when we compared these habitats in pairs, it came to light that nesting heights - when comparing lonely trees - wood segments and tree raws – wood segments - did not show significant differences too, which can be explained by the various conditions provided by the habitats mentioned.
To sum up, during our research the following results emerged:
1. Hooded Crows prefer approximately the same nesting heights in all kinds of habitats, urban environment and tree species.
2. Nesting height depends on the tree species but independent from habitat.