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Intraspecific and intraclutch variability of avian egg
Králová, Barbora ; Jelínek, Václav (advisor) ; Sedláček, Ondřej (referee)
Egg-laying birds have a huge variation between species in terms of number, size, pigmentation, but also in the speckled nature of the eggs. Bird eggs vary not only between species, but also within species, even within a clutch. It is only recently that more speculation has begun about the possible causes of intraspecific variation. Hypotheses about intraclutch variation started to emerge even later. This thesis presents and describes some of the hypotheses dealing with egg variability. One of the most significant factors affecting intraspecific variability is food availability, which in turn affects female fitness. For intraclutch variability, most studies focus on the difference between the last egg and other eggs within the clutch. In many cases, the last egg has a size difference, but also a different amount of pigment compared to the other eggs in the clutch, which are not significantly different from each other.
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Surviving of Northern Lapwing (Vanellus vanellus) chicks in agriculture landscape
Kubelka, Vojtěch ; Šálek, Miroslav (advisor) ; Cepák, Jaroslav (referee)
The variability of egg-size within a bird species reflects different reproductive investments and, besides the intrinsic constraints and particular female quality, it can be affected by environmental factors, too. Moreover, the egg-size predetermines the chick performance. The knowledge of factors influencing precocial chick survival is crucial for better understanding of life-history strategies as well as for endangered species conservation. The Northern Lapwing (Vanellus vanellus) represents a suitable model species for investigation of climate variables effects on egg-size and also to study factors influencing chick survival. Eggs in a total of 714 nests were measured during 13 breeding seasons over period 1988-2014 in South Bohemia and 293 lapwing chicks from 100 broods in 37 localities were monitored in 2013-2014. The mean egg-size through the whole season is positively affected by March precipitation, March clutches also negatively by minus temperatures in March. The higher intensity of rainfall there is during March, the bigger eggs are laid in March and the steeper is slope of decline in mean egg-size during season. This decline is more profound with lower rainfall in April. The effect of habitat is not significant. The body mass and condition of hatchlings is positively correlated with the...
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Surviving of Northern Lapwing (Vanellus vanellus) chicks in agriculture landscape
Kubelka, Vojtěch ; Šálek, Miroslav (advisor) ; Cepák, Jaroslav (referee)
The variability of egg-size within a bird species reflects different reproductive investments and, besides the intrinsic constraints and particular female quality, it can be affected by environmental factors, too. Moreover, the egg-size predetermines the chick performance. The knowledge of factors influencing precocial chick survival is crucial for better understanding of life-history strategies as well as for endangered species conservation. The Northern Lapwing (Vanellus vanellus) represents a suitable model species for investigation of climate variables effects on egg-size and also to study factors influencing chick survival. Eggs in a total of 714 nests were measured during 13 breeding seasons over period 1988-2014 in South Bohemia and 293 lapwing chicks from 100 broods in 37 localities were monitored in 2013-2014. The mean egg-size through the whole season is positively affected by March precipitation, March clutches also negatively by minus temperatures in March. The higher intensity of rainfall there is during March, the bigger eggs are laid in March and the steeper is slope of decline in mean egg-size during season. This decline is more profound with lower rainfall in April. The effect of habitat is not significant. The body mass and condition of hatchlings is positively correlated with the...
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