COMMON KESTREL Falco tinnunuculus ENERGETICS
INTRODUCTION
In my MSc on the Rock Kestrel Falco tinnunculus rupicolus in South Africa
(Van Zyl 1993), life-history differences between South African birds
and Dutch birds could be explained by a possible three factors (or a combination thereof), namely:
- Differences in ecology
- Differences in genetics
- Differences in size
In this section, I will expand on the first of the three points. Diet was very different between South
African and European Kestrels (Van Zyl 1994). This was probably due to
differences in food availability. However, it also affected other behaviour such as the method of
hunting. Both behaviour (energy expenditure) and diet (intake of energy) are related to kestrel
energetics.
This posed the question, is there any difference between kestrel energetics over latitudes? Clearly, the
differences in behaviour and diet already indicate differences, but before I investigate those possibilities,
the differences in basal metabolic rate differences must first be investigated. In a collaborative venture
with Prof. Sergé Daan of the Biological Centre of the
Rijksuniversiteit of Groningen, we measured the resting metabolic rate of kestrels from South Africa, The
Netherlands and Finland. These measurements were done in Groningen during November and December.
A second set of measurements are being currently taken by
Erik Crins. A brief outline of our results follow:
METHODS
RESULTS
DISCUSSION
CURRENT PROBLEMS
REFERENCES
Van Zyl, A.J. 1993. Some ecological aspects of the biology of the Southern African Kestrel Falco
tinnunculus rupicolus. Unpublished MSc Thesis, Univeristy of Cape Town, Rondebosch, South Africa.
Van Zyl, A.J. 1994. A comparison of the diet of the Common Kestrel Falco tinnunculus in South
Africa and Europe. Bird Study 41: 124-130. Abstract.
Any comments on this research are welcome, especially if you have any ideas, or criticisms on the methods,
interpretation, etc. Please mail me!