Conservation needs ethologv.

With the number of species and near-to-natural habitats rapidly dwindling, conservation has become an undebatable necessity. There have been some laudable, successful species conservation projects but there have also been many deplorable failures. The failures are exacerbated by limited funding. Conservationists depend on funding by national government organizations (NG0s) and by private sponsors, more than other practitioners of organismic biology do. To maximize their success, conservationists would be well advised to heed the messages resulting from animal behaviour study (i.e. ethology) and/or to involve ethologists in their projects. Here, I illustrate how ethology can benefit both in situ and ex situ conservation measures; the need for conservation-oriented behaviour research is paramount.

Is avian mortality preprogrammed?

The recent development of life history theory has led to an upsurge of interest in species-specific mortality patterns. Some recent findings on the geographic variation of avian mortality may help to bring more sharply into focus some fundamental issues of ageing (senescence). To say that a bird 'ages' is tantamount to saying that its likelihood of dying increases with age. To what extent are species life spans preprogrammed, to what extent are they the chance product of environmental hazards, and how do these factors interact with each other?

Animal decision-making and the 'Concorde fallacy'.

Both animals and humans appear to commit the 'Concorde Fallacy': they seem to gear their investment into a vital task to their past investment, though ideally they should gear it to the net expected future benefits (= benefits minus costs to complete the task)(1,2). By uncoupling past investment from expected benefits, animals have been variously shown to behave in a Concordian way, though in some cases alternative explanations are still possible. While there is no firm evidence that such behaviour is maladaptive, for instance due to cognitive constraints, there are at least two reasons why Concordian behaviour might be adaptive rather than 'fallacious'. One is that past investment lowers the prospects of future reproduction, thereby altering net expected benefits; the other is that past investment is indispensible to gathering the information necessary for deciding the least costly course of action, i.e. to reap the greatest benefit.

An anti-predator response in the great tit (Parus major): Is it tuned to predator risk?

Two semi-quantitative predictions about the intensity of defence against a predator based on the associated costs and benefits as a function of predator species, were examined in great tits (Parus major) feeding nestlings. One premise was that defence behaviour is adaptive. Defence comprised of vocalizing and homing in on a live raptor near the nest hole. The intensity of defence as judged by two measures of approaching (Minimum Distance, Average Distance) varies with the species of raptor, i.e. sparrowhawk ♀ (Accipiter nisus), pigmy owl (Glaucidium perlatum), and tawny owl (Strix aluco). With the exception of the response to the pigmy owl, defence intensities proved to conform to both predictions; the tits correctly assessed the relative overall risk from each predator ("predator pressure") i.e. its degree of specialization on great tits, and the immediate risk of defence. The failure to verify the predictions regarding the pigmy owl is thought to derive from our incomplete assessment of the cost function and/or from the response being mal-adaptive.The male takes a greater risk, exceeding the female's by an amount independent of the species of raptor. The sexual difference remains functionally unexplained.

Cultural transmission of enemy recognition: one function of mobbing.

There are at least ten suggested hypotheses for the function of mobbing predators by fish, birds, and mammals. Experiments with captive European black-birds support one of these-the "cultural transmission hypothesis." Perceiving a mobbing conspecific together with a novel, harmless bird induced blackbirds to mob the innocuous object. The mobbing response persisted during subsequent presentations of the novel bird alone, which was more effectively conditioned than an artificial control object. Enemy recognition could be culturally transmitted along a chain of at least six individuals.

[Selection of strays from the group by predators during prey]. / Untersuchungen zur Selektion durch Räuber gegen Vereinzelung der Beute

Equally sated three-spined sticklebacks (Gasterosteus aculeatus) that had a free view of stray individuals and of a swarm of Daphnia magna preferentially preyed upon the strays; the resulting risk to the strays increased with swarm density (a leads to c leads to e in Fig. 1). This applied also to situations with constant swarm numbers but varied density (a leads to b, d leads to e). The results from two experiments with equal swarm density (b/e, c/d) suggest selection to be affected also by swarm number and/or volume.