Naturalists for many years have known that birds sing most at dawn and at dusk, but to which of many physical variables they are responding has not been completely determined. This problem has taken on importance in the field of wildlife management because calling rate has been used as an index of abundance for numerous game birds, namely the Pheasant, Phasianus colchicus( Kimball, 1949); the Mourning Dove, Zenaidura macroura (McClure, 1939); the Bobwhite Quail, Colinus virginianus (Bennitt, 1951; Rosene, 1957): and the Woodcock, Philohela minor (Pitelka, 1943). Of the possible variables which can influence calling in birds, light intensity has received the most attention. Haecker (1916), using a crude optical light meter, found a definite and high correlation between time of beginning morning song and light intensity. In 1924 he published findings with the same conclusion after measuring light intensity photometrically. Dorno (1924), in repeating part of Haecker's work, came to the conclusion that light was significant, but that the variation in the time of beginning morning song; and sunrise was due to differences in dispersal of light rays rather than actual light intensity. This dispersal was due, in his opinion, to latitude and season of the year. Since that time many workers have been concerned with the problem . The first American to deal with light intensity as the factor that governs time of morning calling was Craig (1926). He found a close correlation between early morning song of the Eastern Wood Pewee ( Contopus virens) and the curve of civil twilight. Walker (1928) found that the length of time before sunrise a bird sings is probably dependent on the total amount of light present, but that weather factors influence song to a great extent. In agreement with these findings were those of Lutz (1931) studying singing in the House Wren (Troglodytes musculus). He found that one individual began to sing at almost the same time on each of 24 mornings. If the morning was bright, song came earlier; if couldy, it came later, but time never varies more than 15 minutes. Wiens (1960) stated that the song of the Cardinal (Richmondena cardinalis) was closely associated with sunrise during April. He recorded calls beginning 10 minutes )plus or minus 3 minutes) before sunrise during this month. Eynon (1960), in compiling field notes of the late Aldo Leopold, showed that the first morning songs of several passerine and game birds are closely associated with very low light intensities that occur during the twilight before sunrise. Studies showing effect of light intensity on animal activity are not limited to birds. Alexander and Moore (1958), studying singing in two species of Cicada (insects), found that both are sensitive to changes in light intensity. Singing increased as the sun came up and decreased as the sun passed behind a cloud. They attempted to stimulate singing with taped song under cloudy conditions, but only one species responded.Steven (1959) showed that schools of fish occurring during daylight hours break up as light falls below 0.1 foot-candle. He stated that there was no sudden change from day to night behavior patters at an level of light; the change was progressive. Other factors which have been shown to affect time and rate of bird calling are temperature, wind, and rain. Groebbels (1925) believed that early morning singing was a direct response to prevailing low temperatures. This study measure the composite and individual effects of time of day, season, light intensity, wind, rain, and temperature on calling. An attempt was made to apply correction factors to make possible more standardized calling counts. Observations were made on penned Chukars to relate sex and social organization to rally calling.

The diploma paper aims to appraise the composition of menu offered to pupils aged seven to twelve attending the Elementary School (ES) based in Suché Vrbné, a quarter of České Budějovice. The menu was assessed for its contents of macronutrients and a range of chosen micronutrients considered to meet nutritional demands of school children. The research covered 64 examinees (of both sexes) from the second, fourth and sixth grades, and was organized as a test of their dietary habits and physical a tivities. The paper deals with: -Nutritional quality of school lunches; -Weights and statures of children from the relevant grades measured at the beginning and the end of the appraised span of time, with the observed changes evaluated; -Average cost spent to prepare one lunch; -Variety of the food and the numbers of specific dishes taken in a month; -Adherence to the recommended alimentary basket; -Weights of the different components of lunches; -Nutritional test designed to examine dietary habits and physical activities of c ildren aged 7 to 12; -Changes in the diet of children moving up to the senior stage of the Elementary School; -Formulating hypotheses focused on drinking regimen, Body Mass Index (BMI) and physical activities. Percentage of nutrients derived from lunch, represent the proportion of recommended daily intake for the day. The ideal figure of 35 % of the recommended daily energy intake was achieved only in girls of the 4th grade. The other categories of boys and girls ranged between 5 % and 9 %. As regards proteins, these were supplied in the above-the-limit quantities to the 2nd and 4th graders, while the 6th graders received 79,65 % to 82% of the recommended daily intake. Fats kept at the optimal level of 30 % to 35 %. Saccharides stayed at the low level of 19 % to 24,69 % for the entire time of monitoring. Fiber was found to maintain the acceptable level of 29 % to 37,41 %. As regards the macroelements, calcium supply was insufficient - at 15,0 % to 18,46 % only a small portion of what is desirable. Magnesium intake was at 41,86 % to 59,1 %. Potassium reached on average 53,6 % to 59,66 %. As to microelements, iron was supplied at 42,37 % to 48,91 %; zinc at 41,15 % to 52,91 %; selenium at 59,1 % to 175,21 %. Vitamin A reached 60,78% to 89,23 %; vitamin E was at 38,66 % to 55.1%, and vitamin C at 58,81 % to 66,0 %. Vitamin B6 was supplied in the quantity of 38,50 % o 47,83 %. Vitamins B6 and B12 were supplied in above-the-standard quantities for the whole monitored period. Measurements of weights and statures were related to the age and then used to calculated the BMI - thus one 2nd grade girl was found overweight and one boy and another girl of the same grade were found obese. Pupils of the 4th grade kept within the optimal figures. In the 6th grade two girls and four boys registered overweight. Expressed in percentages, the research has showed that in the 7 to 12 age bracket 3.2% of children were obese and 9.15 overweight. The average cost of lunch preparation was 42 CZK. The numbers of specific dishes were revealed inadequate for pulses and fish. The share of fruit was duly met while vegetables were insufficient. Low was observed also the proportion of milk and sweet & meatless dishes. Conversely, the frequency of dishes made of chicken and pork was excessive. Yeast and pulse soups were served optimally, as suggested by the Ministry of Health. Inspection carried out in view of the alimentary basket specified in Decree 107/2005 disclosed these values as average for the entire period of interest: meat 92,9 %; fish 69,4%; milk 54.8 %; milk products 72.9 %. Fats were supplied at the level of 69,3 %; sugar 46 %; vegetables 59.9%; fruit 124%; potatoes 87,4 %; and pulses 54,4 %.