No description available.

Mate-guarding is performed by many monogamous species, a method used by individuals to physically prevent competitors of the same sex from mating with their partners. This behaviour is most often displayed during the fertile period (i.e. when females can be fertilized). In this study I focused on the genetically and socially monogamous species, the Siberian jay (Perisoreus infaustus), in which I observed mate-guarding behaviour. The Siberian jays did change their behaviour and increased their aggression in the fertile period, a sign of mate-guarding. This result also suggests that even socially and genetically monogamous species do increase their aggression during the fertile period. This indicates that fidelity still requires an investment in mate-guarding to limit extra-pair mating opportunities. Mate-guarding should then be possible to find in species where there is at least a theoretical opportunity for extra-pair matings. / Mate-guarding är en metod använd utav många monogama arter, metoden används för att fysiskt hålla konkurrenter utav samma kön borta ifrån sin partner för att försäkra sin egen parning. Denna metod beskådas oftast under tiden honan är fertil. I denna studie fokuserade jag på den genetiska och sociala monogama arten Lavskrika(Perisoreus infaustus) där jag observerade mate-guarding beteende. Lavskrikans beteende förändrades mellan perioden då honan icke var receptiv och hon var fertil, aggressionen ökade för båda könen under den fertila perioden vilket är ett tecken utav mate-guarding beteende. Detta resultat föreslår att socialt och genetiskt monogama arter ökar sin aggression under tiden honan är fertil, det föreslår även att trofasthet fortfarande kräver hög investering utav mate-guarding för att minska riskerna utav otrohet. Mate-guarding beteende borde då finnas hos arter med en teoretisk möjlighet för otrohet.

Proefschrift--Letteren--Katholieke Universiteit Nijmegen, 2000. / Notes bibliogr. Index.

Texte remanié de: Habilitationsschrift--Theologische FakultätcFreiburg im Breisgau--Albert-Ludwigs-Universität, 2001. / Bibliogr. p. 756-817.

Thesis (Ph. D.)--Ludwig-Maximilians-Universität zu München, 1970. / Vita. Includes bibliographical references (p. 110-111).

Thesis (Ph. D.)--University of Florida, 1984. / Description based on print version record. Typescript. Vita. Includes bibliographical references (leaves 211-224).

No description available.

The purpose of the present series of experiments was to examine in some detail the characteristics of short-term memory in object discrimination learning set ( ODLS ) -experienced bluejays (Cyanocitt a Cristata ) . ODLS consists of the presentation of a series of two -choice simultaneous discrimination problems. Typically, non-correction procedures are used with position irrelevant throughout. Each new problem is defined by the introduction of a new pair of discriminative stimuli ODLS acquisition is defined as an increase in the speed of solving new problems accompanying experience with problem solving. Most comparative research performed with ODLS as the basic paradigm has concentrated on demonstration of ODLS acquisition . The only exceptions to this have been a large number of experiments with primates as subjects , particularly rhesus and other macaque species. The present experiment was designed to provide more analytic information about ODLS behavior in a species vastly different from the rhesus monkey.

No description available.

In the depleting density experiment it was found that the jays did respond to prey depletion and that the jays appear to use a hunting by expectation rule. These data suggest that the rule a predator uses depends on the distribution of prey.