Thesis on a specially studied subject
Predator-prey study of
avian predators and African Mastomys mice – prey composition analyses
of avian predator pellets
multimammate mouse, Mastomys natalensis
is an important rodent pest in sub-Saharan Africa. It acts as natural reservoir
in several human pathogens and cause severe damage to agricultural crops. Rodent
management today mainly rely on the use of rodenticides but this control method
in general suffers from lack of knowledge and has often resulted in large amount
of chemicals being distributed in the environment without the desired control
effects. Alternative control methods that are far more environmentally friendly
A few studies have indicated that predation is an important mortality factor in M.
natalensis populations and this has opened up for an interest in
understanding the biological effects of predators on M. natalensis
populations. A recently terminated study in central Tanzania in East Africa
therefore focused on the effects of applying different predation pressures to M.
natalensis populations in small, cultivated fields. In this study a large
amount of pellets regurgitated from avian predators were collected around perch
poles and under trees in a 60 ha area of mixed cultivated and fallow land. The
frequency of pellets collected over time shows that there is a markedly seasonal
fluctuation in the avian predation pressure, but further analyses of the pellet
material are needed to obtain more information on the prey animals.
Avian predators may prefer certain hunting habitats to others according to which
of their senses are involved in hunting. If sight is an important hunting sense,
the predator may prefer sparsely vegetated and open areas for hunting, but if
hearing is an important hunting sense, it may also hunt in more densely
The social structure in a rodent population may imply that certain individuals
are more exposed to predation risk than others. A social subordinate status, may
force the individual to forage in areas with high predation risk. Predators may
therefore selectively predate on such more exposed groups of prey individuals
and thereby affect the population structure. Selective predation can be related
to for example sex, age and size of the rodents.
The master study should focus on the prey composition of avian predators through
analyses of the pellet contents. The contents of the pellets should to be sorted
into prey groups; i.e. insects, birds, shrews and rodents, and for rodents be
identified to species when possible. Jaw measurements and tooth wear
measurements should be taken on M. natalensis prey material. In order to
determine whether predators selective predate on certain age or size classes of M.
natalensis, both the jaw measurements and the tooth wear measurements may be
correlated to M. natalensis size classes (body mass) and subsequently be
compared to the size composition of M.
natalensis in the surrounding habitat.
the project is of interest to you please contact:
DK-2800 Kgs. Lyngby
Tlf. 45 87 80 55, (reception) 89 99 39 01 (direkte)
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