No abstract

Dementia is a disease that brings with it various limitations in the afflicted person's communication with others. The purpose of this study is to explore, not the limitations, but the capacity of the demented person to communicate under conditions that differ from the everyday life of the care institution. Group dance therapy sessions with elderly, demented persons were video-taped and analysed with a focus on how verbal and non-verbal modes of communication were used by the participants. The ways the demented persons use body movements, free dance movements, speech and singing in different combinations is described and discussed in terms of different expressive modes, where body movements are used to substitute or support speech as well as to express thoughts, memories and emotions. The results from the study indicate that under conditions that allow for different modes of expression, the communication of the demented person can be found to be rich and varied in expression and content.

Observations of freshwater drinking in Eiders feeding primarily on mussels led us to hypothesize that the highly saline sea water enclosed in mussels could cause salt‐related dehydration problems in the ducks, since they consume entire mussels. The proportion of sea water increases with increasing mussel size. Smaller duck species are more sensitive to the higher salt content of larger mussels than are larger ducks; however, salt stress may be avoided by feeding in habitats with lower salinity, by feeding on less salty food items, by utilizing smaller mussels, by drinking fresh water, or by employing low energy foraging techniques. A possible evolutionary strategy for solving the salt problem might be to increase body mass, enabling ducks to utilize larger mussels without passing an upper salt consumption limit. At the same time, foraging on larger mussels is more economical. Although large size facilitates the utilization of brackish and marine environments, it may be selected against in ducks breeding in fresh water, where fish competition may reduce optimal food item size. In conclusion, salinity is an important habitat barrier in both breeding and overwintering diving ducks, but there are various ways of crossing this barrier. To understand better how ducks utilize their habitats, however, it is necessary to measure habitat salinity levels and the size of both ducks and their preferred and less‐preferred food types.

Early-arriving small male willow warblers (Phylloscopus trochilus) in good body condition were relatively successful at defending their territories. Later arriving neighbouring males tended to be larger but had poorer body condition. When males arrived, food resources were limited but increasing. The song rate varied among males during the period before pair formation and was positively correlated with the male body condition index. Song phrase length and song rate decreased after the performance of other activities, which suggests that singing was energy demanding. The sequence of pairing correlated well with male arrival, song rate, and food abundance. Females apparently take food abundance into account when selecting a mate. A model is presented to explain the adaptation of male and female willow warblers to the avaikbility of food resources in time and space and the role of the male in securing a high-quality breeding territory.RCsumC : Les petits miles en bonne condition physique du Pouillot fitis, Phylloscopus trochilus qui arrivent t6t sont relativement efficaces dans la defense de leur territoire. Les miles avoisinants qui arrivent plus tard ont tendance a etre plus gros, mais sont en moins bonne condition physique. A I'arrivCe des miles, les ressources alimentaires sont limitees mais en croissance. La frequence des chants varie chez les miles au cours de la formation des couples et est directement reliee au coefficient d'embonpoint des miles. La longueur des phrases et la frequence des chants diminuent aprks les autres activites, ce qui semble indiquer que l'emission des chants est une activite exigeante du point de vue energktique. La sequence de la formation des couples est en correlation positive avec l'arrivee des miles, la frequence de leurs chants et l'abondance de la nourriture. Les femelles tiennent apparemment compte de l'abondance de la nourriture lors de leur choix d'un partenaire. On trouvera ici un modkle capable d'expliquer l'adaptation des pouillots miles et femelles a la disponibilite des ressources alimentaires dans le temps et dans l'espace et le r61e joue par les miles lors du choix d'un territoire de reproduction de haute qualite. [Traduit par la Redaction]

1 . On sex-specific foraging behaviour in the Willow Warbler, Phylloscopus trochilus. Can. J. Zool. 69: 462-470. The foraging behaviour of Willow Warblers (Phylloscopus trochilus) in relation to the availability of their insect prey was studied at the Tovetorp Field Station and at the Royal Park of Djurgirden, Stockholm, Sweden, from 1985 through 1989. The numbers and types of arthropods available to Willow Warblers fluctuated throughout the breeding season. In general, most arthropods were found on the underside of the leaves. Males spent more time gleaning and less time hovering and fly catching when preying chiefly on aphid nymphs then when foraging on other arthropods on birch before budbreak. They performed more fly-catching behaviour and tended to forage in taller trees than did females. Dissimilarities in foraging behaviour between the sexes were attributed to differences in wing length and wing shape. Because females are smaller and have less pointed wings they are better adapted for hovering than males. Consequently, females were better at capturing prey on the underside of birch and willow leaves, which was abundant during the egg-laying and brood-rearing periods. Thus, in birch and willow, females hovered more frequently than males, but there was no difference between males and females foraging in spruce, pine, and oak.