|
|
Influence of the intensity of begging on the rate of predation in the common sandpiper and common cuckoo
ČAPEK, Jan
In this research, I examined whether the louder calls of the common cuckoo (Cuculus canorus), a nest parasite, would increase the rate of predation on the nest of the red-backed shrike (Lanius collurio), whose nestlings call at a lower volume. The experiment was conducted during both the nesting season of the red-backed shrike, primarily in June, and in the autumn of 2023. During the spring trials, nests were situated within bushes, whereas in the autumn trials, they were positioned on the ground. Each experiment involved three nests, each subjected to a distinct audio recording: one featuring the vocalizations of a young common cuckoo, another with those of nestlings of the red-backed shrike, and a third serving as a silent control. Predation rates were assessed across these nests to determine whether certain recordings elicited higher predation rates compared to others.
|
|
|
Red-backed shrike (\kur{Lanius collurio}) versus Common cuckoo (\kur{Cuculus canorus}): Clutch variability and egg recognition
KRAUSOVÁ, Ladislava
In this work, using photography, I tested the red-backed shrike (Lanius collurio) intraclutch egg variability and compared it with the interclutch egg variability. The effect of colour, size, volume and maculation as well as chromatic and achromatic contrasts were evaluated. Moreover, I tested ability of the red-backed shrike to recognize artificial cuckoo eggs and artificial shrike eggs, evaluate the rejection rate of these eggs, and compare it with the rejection rate of conspecific eggs. I showed that shrikes have low intraclutch variability and high interclutch variability in all measured parameters. Such variability might be an adaptation against brood parasitism. In addition, I found out that the shrikes' ability to recognize and reject a parasitic egg is significantly higher than expected.
|
|
| |
|
|
The role of the face and the body size in predators' recognition by untrained birds
Fišer, Ondřej ; Fuchs, Roman (advisor) ; Petrusková, Tereza (referee)
The face plays an extremely important role in human communication. It enables individual recognition and provides other information about the person, such as social or emotional information. Human psychology has shown that face recognition uses a specific cognitive process called holistic processing. In recent decades, it has been shown to play an important role in animal communication as well. In the first part of my thesis, I tested whether changing the uniform configuration of a bird's face would affect the ability of the red-backed shrike (Lanius collurio) to recognize a potential predator. Due to unfavourable conditions in both breeding seasons when the experiments were conducted, no firm conclusions can be drawn from the results. They only suggest that the shrike perceives the configuration changes. An essential characteristic of all predators is their size, which affects the ability of prey to defend themselves. Several studies have already found that birds discriminate between different predators of different sizes. In the second part of my thesis, I evaluated experiments in which shrikes were exposed to dummies of two predator species with modified size. The shrikes responded with less aggression to the enlarged jays, whereas aggression increased only slightly to the shrunken crows. Thus,...
|
|
|
Antipredační chování pěnice vlašské (\kur{Sylvia nisoria})
BURŠÍKOVÁ, Markéta
My study was aimed to describe the antipredator behaviour of Barred Warbler against five avian mounted dummies differing in the level of threat they represent for the Barred Warbler: Eurasian Sparrowhawk (Accipiter nisus), Eurasian Jay (Garrulus glandarius), Black-billed Magpie (Pica pica), Red-backed Shrike (Lanius collurio), and Domastic Pigeon (Columba livia f. domestica) using the experiments carried in the vicinity of the nests with fledglings of Barred Warbler. The next goal of my study was to discover the relationship between the Barred Warbler and the Red-backed Shrike nesting together.
|
|
| |
|
| |
|
| |
|
|
Antipredator defence of Red-backed Shrike (\kur{Lanius collurio})
VLAŠÁNKOVÁ, Anna
I studied the antipredation behavior of the Red-backed Shrike (Lanius collurio) in one breeding season. In random sequence I placed imitation of Eurasian Jay (Garrulus glandarius) in three distances from the Shrike´s nest - 2, 4 and 10 meters. I compared dofferences in Shrikes reactions. I also tested influence of others factors of environment on mobbing intensity - age of breeds, size of clutch, sex, amount of surrounding shrubs and size of nest shrub
|
|
|
Antipredation behaviour of the Red-Backed Shrike (\kur{Lanius collurio}) against corvids
NĚMEC, Michal
In previous studies with stuffed dummies, we found interesting difference in nest defence of Red-Backed Shrike (Lanius collurio) against two similar nest predators: Jay (Garrulus glandarius) and Magpie (Pica pica). Jay was attacked very intensively, whereas Magpie almost wasn´t hited and Shrikes seemed to keep in cover. Here, I describe the antipredation behavior of the Red Backed Shrike against another stuffed corvids presented closely to Shrikes nests: Jay (Garrulus glandarius), Common Nutcracker (Nucifraga caryocatactes), Rook (Corvus frugilegus), Crow (Corvus corone) and Raven (Corvus corax). I found Jay and Nutcracker to be attacked by Shrikes very strongly, whereas Rook, Crow and Raven were attacked rarely (Shrikes only flied around them or sit at a distance, watching the dummy, sometimes accompanied with alarm-calls). Shrikes response is affected mainly by kind of predator, by age of youngs and by quality of concealment of nest. More - www.mn.ic.cz
|
guest ::
