Showing papers on "Territoriality published in 1976"

Schooling as a mechanism for circumventing the territoriality of competitors

Abstract: The herbivorous striped parrotfish Scarus croicensis exhibits pronounced within- site variability in its social behavior: some individuals hold permanent feeding territories while others form feeding schools. Members of both of these classes are subordinate to the omnivo- rous damselfish Eupomacentrus planifrons which strongly inhibits the feeding of parrotfish in its own feeding territories. To a lesser degree, territorial S. croicensis, whose territories are superimposed on those of E. planifrons, also inhibit the feeding of nonterritorial conspecifics. Data show that nonterritorial S. croicensis in schools feed at higher rates, and are attacked by territory owners less often than nonschooling nonterritorials. This supports the hypothesis that schooling enables those individuals to circumvent the territoriality of their competitors. Non- territorial S. croicensis apparently constitute that proportion of the population that cannot obtain feeding territories, probably primarily as a result of the aggressive activities of E. planifrons, and schooling thus promotes the coexistence of these territorial and nonterritorial forms. A number of other teleost species, benthic-browsing omnivores, and herbivores, that associate with S. croicensis schools and are subject to strong aggression from E. planifrons, derive benefits from this association in the same way as the schooling parrotfish do. Predators that associate with S. croicensis schools, and that are little attacked by E. planifrons, benefit instead by feeding on organisms disturbed by the feeding school.

Regulation of food supply by feeding territoriality in the rufous hummingbird

Abstract: This field study of female and immature migratory rufous hummingbirds (Selasphorus rufus) reveals that their feeding territories are closely regulated in size to maintain environmental reserves of ...

A Critique of Interspecific Territoriality and Character Convergence

Abstract: Cody (1969) suggested that species may converge in appearance or voice because similarities increase interspecific aggressiveness, which leads to the individuals of two species maintaining mutually exclusive territories in a common habitat. The advantage of such behavior is that it results in the exclusion of food competitors within the individuals' territories. Thus, according to Cody, interspecific territoriality is adaptive. In 1971 I published an interpretation of observed cases of interspecific territoriality, in which I assumed that interspecific territoriality was aggression that evolved in intraspecific contexts but was misdirected toward individuals of other species which possessed similar features that normally stimulated intraspecific territorial aggression (Murray 1971). I argued that mutual interspecific territoriality is maladaptive for at least one of the species because the subordinate species would eventually be excluded from otherwise optimal habitat, but I did not exclude the possibility of the existence of cases of adaptive interspecific territoriality. The two hypotheses, then, seem contradictory. The first assumes that cases of mutual interspecific territoriality are adaptive, while the second assumes that they are not. Some authors studying birds (Barlow et al. 1970, Brown and Orians 1970, Cheke 1971, Rohwer 1972, 1973, Kroodsma 1973, Emlen et al. 1975), fishes (Myrberg and Thresher 1974), hermit crabs (Hazlett 1972 a, b), and flowers (Levin and Schaal 1970) have found Cody's hypothesis reasonable. It has appeared as an annual review article (Cody 1973) and as a portion of a book (Cody 1974), and has been described in at least two ecology textbooks (Ricklefs 1973, Smith 1974). Because Cody's hypothesis is widely accepted and is contradictory to my own, I wish to examine it and the evidence for it in some detail.

The Psychological Role of Property Rights in Human Behavior

Abstract: A number of psychologists are turning their interests to the problems of property rights in human behavior. This is a recent development, and the relevant work is found in studies of territoriality. A number of basic theories of territoriality are summarized here, with comments on the problems of defining the term. It has further been proposed that territories affect humans at three levels of analysis, including interaction with social rank distinction, reduction of disorder and complexity, and chaining individual behavior acts. From a subjective point of view territories are probably connected with a personal sense of security, control, self-determination, identity, and continuity.

The Behaviour of Males of the Solitary Bee Osmia r uFa (Megachilidae) Searching for Females

Abstract: I. Most O. rufa males make general searches for females near nests and flowers. 2. A few males spend most of their time in the nesting area and defend individual resting places from other males. 3. Males detect females more readily the closer the latter are to nests, but they pounce on other males and insects of similar size as well. 4. Males can mate several times, but females mate only once. 5. The behaviour of O. rufa males searching for females is regarded as intermediate between the general searching of some megachilid species and the territoriality of others.

Theoretical and Empirical Issues with Regard to Privacy, Territoriality, Personal Space and Crowding

Abstract: one which concentrates on the transformations from animal to human spatial experiences. This approach argues that man’s spatial behavior is hierarchically structured vis-6-vis the varying levels of evolutionary development reflected in his CNS. An outline of this hierarchical structure and an attempt to relate it to the conceptual effort in this special issue are related below. Table 1a outlines various spatial experiences and their hypothetical evolutionary levels (Esser, 1973). Table 1 b is a preliminary attempt to outline how these transformations might be expressed on the human level.

Factors affecting the evolution of group territories in babblers (Turdoides) and long-tailed tits

Abstract: The thesis is divided into three parts. In part I the ecology and behaviour of the Jungle Babbler Turdoides striatus are described and in part II comparable data on the Common Babbler T.caudatus are given. In part III some observations on other species of Turdoides and on the Long-tailed Tit Aegithalos caudatus are described and a general model for the evolution of group territoriality and co-operative breeding is presented. A description of the habitat in which Turdoides studies were carried out is given in an introduction which includes data on seasonal cycles and a brief outline of the ecology of the resident avifauna. A summary is also given of the biology of Turdoides species, which live in permanent exclusive groups of 2-20 birds, holding common territories throughout the year. In most cases only one pair breeds during the season, but many non-breeding group members take part in nesting activities, particularly feeding the nestlings. The aims of the study are summarised in two questions: "What circumstances make it advantageous for more than two birds to share a territory?" "What circumstances make it advantageous for birds to assist in rearing conspecifics which are not their own offspring?" Part I contains four chapters. The first deals with the population dynamics of the Jungle Babblers within the main study area on the outskirts of Delhi, India. Methods used to estimate recruitment, survival, interchange between groups, group structure and the degree of relatedness between group members are described. Territories are classified into three types on the basis of the vegetation that they contain and differences are found between these categories in the number of young reared and the number of birds per group. Large groups, which occupy territories mainly in woodland, probably produce most of the recruitment into the adult population. Birds from these groups may move into territories outside woodland to breed, but breeders in woodland territories are probably recruited from territories of a similar type. Although woodland groups are large and have a high breeding success there is no evidence that the number of non-breeders in the group influences the reproductive success of the breeding pair directly. In Chapter 2 the territorial behaviour of the Jungle Babbler is described. Groups do not cover their home ranges evenly, but tend to concentrate their activities in a small portion, usually comprising closed-canopy woodland with a dense understorey, known as the 'core area'. This was arbitrarily defined as the area within which 50% of the observations of a particular group were made and it comprised about 17% of the total home range recorded. Use of different parts of the home range varies with the time of year and territorially appears to be most marked at the start of the two peaks of breeding activity. During the winter groups often forage together for periods of several hours. The size of core areas is correlated with the number of birds in the group. Groups which changed their numbers from one season to the next showed corresponding changes in the extent and quality of their core area. Taken in conjunction with evidence from Chapter 1, this suggests that large groups tend to be stable and persistent, while small groups are vulnerable to encroachment by others and hence tend to be ephermeral. Chapter 3 describes five aspects of intra-group behaviour in relation to the age, sex and breeding status of the participants. These are allo- preening, sentinel behaviour, leadership, play and roosting. A rough concordance was found between hierarchies based on participation in allo- preening, sentinel and leadership behaviour, but among non-breeding adults differences were found between the sexes. If these three behaviour patterns function partly to express the social status of the participants then differences between males and females are probably related to their respective breeding strategies; males striving to become breeder in their natal group, while females normally move elsewhere to breed. Play behaviour occurs mainly among first year birds, particularly between 2-4 months after fledging, and may be-associated with the establishment of dominance relations among siblings. At the same age they show various signs of social indiscipline which may contribute to the unsettled behaviour shown by some groups while going to roost. The behaviour of non-breeding birds during nesting is described in Chapter 4. All non-breeders more than one year old contribute to feeding the nestlings and driving off potential predators, but a greater share is taken by males than by females. Like the differences in other aspects of behaviour, this difference between the sexes may be attributable to differences in their strategies for breeding. Non-breeders also take some part in incubation, but do not participate in nest-building. The introduction to part II explains how limitations on the visibility of Common Babblers in the field led to an emphasis on different aspects of their behaviour. Chapter 5 covers population dynamics and movements, and also deals with seasonal weight changes. These suggest that some birds which were trapped in mid-winter may have been close to the minimum weight guaranteeing survival and it is possible that the availability of food at this season may be a factor controlling the population. The proportion of unrelated birds found in groups of Common Babblers appears to be higher than estimated for Jungle Babblers. Females leave their natal groups in their first summer and a few males were observed to breed at one year old. The population of Common Babblers in the study area declined throughout the period of the study and this may have affected observed rates of immigration. In some Common Babbler groups only one pair nests during the season, but in others the same male nests successively with two different females and in a third situation two pairs nest simultaneously. There are significant differences between groups exhibiting these three patterns in the number of birds per group and in the density of birds within the territory. In Chapter 6 the relationship between group size, population density and territorial area is described for the main study area and also for populations in the Salt Range, Pakistan. The results of some inconclusive removal experiments are described. Behaviour at the nest was studied in greater detail for the Common Babbler than for the Jungle Babbler and the results are described in Chapter7. Incubation is carried out mainly by the breeding female. Non-breeding females do not usually participate in feeding the nestlings, being driven from the vicinity of the nest by the breeding female. A correlation was found between the number of non-breeders assisting at the nest and the number of nestlings in the nest on day nine, but a causal relationship could not be established. In part III, Chapter 8, brief observations on five other species of Turdoides are described. A comparison between population densities and group sizes for all the populations of Turdoides studied reveals that there is a close correlation between these parameters. The variance in group size within populations is also similar, suggesting that factors controlling group size operate in a similar way on populations in different habitats and at a wide range of densities. The behaviour and ecology of the Long-tailed Tit, studied over a period of nine months in Wytham Wood, Oxford, are described in Chapter 9. In winter stable groups of 10-25 birds hold territories. In February these groups break up into pairs during the day although members of the same winter group continue to roost together. Pairs nest within their winter territory in most cases, although there is some movement between territories, mainly by females. Non-breeding birds contributed to feeding the nestlings at six out of the ten nests where young survived at least seven days. Three single 'helpers' of known sex included two males and a female and these may have have been non-breeders, which were estimated to constitute 9% of the population. In one case a pair which had failed in its nesting attempt was apparently involved in helping. In Chapter 10 the factors considered to play a major part in the evolution of group territories are described. It is assumed that groups form by the retention of offspring within the parental territory and the development of tolerance by the adults is considered crucial in the origin of group territories. It is suggested that high adult survival in a situation where the habitat is fully saturated with territory holders creates the optimal conditions for group territoriality, but other important factors are also described. Arguments are put forward to suggest that the advantages of group territory are likely to be greater for non-breeding group members than for the breeders, and this inequality is proposed as an important factor in the origin of co-operative breeding. In situations where remaining in the parental territory increases the inclusive fitness of the non-breeder, but does not increase that of the breeders, then non-breeders may be able to make their presence acceptable to the breeders by assisting their reproduction. This hypothesis explains the observation that positive assistance by non- breeders occurs mainly in species where co-operative breeding appears to be of relatively recent origin. In situations where group territoriality is well developed it is proposed that competition created by the addition of new members to the group is sufficient to offset possible advantages accruing to the non-breeder through kin selection, and hence no positive assistance occurs.

Theoretical and Empirical Issues with Regard to Privacy, Territoriality, Personal Space, and Crowding

Abstract: Less then ten years ago, Edward Hall could accurately acclaim that space was indeed a &dquo;hidden dimension&dquo; (Hall, 1966). Since the early work of Hall (1966), Sommer (1969), and others, considerable research has ensued in an attempt to unravel some of the complexities of spatial behavior. While the spatial dimension is no longer a hidden one, considerable theoretical ambiguity and methodologi~;al difficulty remain in our attempts to understand spatial aspects of the human-environment interface. Recent reviews of crowding (Stokols, this volume), personal space (Evans & Howard, 1973), human territoriality (Edney, this volume), and spatial behavior in general (Esser, 1971; Altman, 1975) have consistently pointed out that our understanding of spatial behavior, especially with regard to humans, is at a very early stage. In particular three problematic areas have been identified. First, there is a striking paucity of hypothetical and theoretical analysis in much proxemic research. Second, efforts to address inconsistencies among data and develop linkages between related theoretical constructs generally have been lacking. Third, it is necessary to delineate more adequate measurement techniques taking into account the

Some observations on social organisation and behaviour of springbok in the Jack Scott Nature Reserve

Abstract: Aspects of social organisation and behaviour of springbok were observed in a small population in the Jack Scott Nature Reserve, Transvaal. Single adult males were frequently sighted in particular localities, usually either alone or with a female or nursery herd. Observations of intolerant behaviour on the part of such males towards other male springbok suggested territoriality. In one instance a new adult male was observed in an area where a known adult male had been seen repeatedly, and the latter was seen elsewhere. A few notes on reproductive behaviour and mother-young relationships are presented.

Wintering Avifauna in Ramnagar, North-western India

Abstract: 1. I stayed from 31st Oct. to 6th Dec. 1973 at Ramnagar, Jamu and Kashimir, north-western India, and investigated the wintering birds. The relationships between habitat structure and feeding behaviors of wintering birds were observed and discussed. 2. The study area is situated in the mountain rural village and has the artificial vegetations. The environment of birds may be divided into eight habitats, i.e., pine woods, deciduous woods, Leguminosae thin woods, bushy area, grassland, river, paddy field, and human habitation. Each habitat has a characteristic species composition and relative abundance corresponding to the structure of the habitat. 3. Of the wintering birds of Ramnagar, the commonest are the birds of Turdinae. Each species of this group is separated into the characteristic living spaces. There are three types, 1) ground attacking without watching posts, 2) ground attacking from watching posts on bush, and 3) flycatching to the space between trees from watching posts. In winter in Ramnagar, the living space of typical Muscicapinae is left vacant. But some species of the Turdinae enter into the lower space of the Muscicapinae's space. 4. There are three types of aggregation in birds; 1) mobbing assembly, 2) hunting party, and 3) chorus group. The mood of noise attracts some birds from their specific living space and promotes to the more available space exploitations. Such assemblies suggest the creation of the biological space by birds. 5. Conspicuous winter territories were observed. Especially, some species of the Turdinae have solitary territories, for example, the flycatching members and the ground attackers in openland. However, all observed cases are of intra-sexual territoriality. The males of Plumbeus Redstart are territorial, but the females are the non-territorial solitary. In the Blue-headed Redstart, both males and females are intra-sexually territorial, but had no inter-sexual territoriality.