Nearby Territories Research Articles

Migration and accumulation of heavy metals in disturbed landscapes in developing ore deposits, East Kazakhstan

This paper studied the contents of heavy metals and their accumulation in the disturbed landscapes in ore deposits of East Kazakhstan. A total of 14 sites were examined in Zyrynovsky and Tishinsk deposits and Ridder town, and 50 soil samples were taken. Results indicated that the contents of heavy metals in the soil reached the maximum permissible concentration. Emissions of the zinc plant negatively affected the soil of nearby territories. In the remediated areas, a high concentration of heavy metals was observed at a depth where the bulk soil borders the rock. Accumulation of heavy metals on the surface of the remediated areas occurred due to biological accumulation in the plant. Plants transmitted heavy elements through the root system to the upper vegetative organs, making them accumulate in the upper layers of the soil. The heavy metals migrated and accumulated from the lower layers to the surface layers of the soil. The absence of soil meso-fauna resulted in the contamination of soil by heavy metals. The analysis of water samples, taken from the waste storages and the waste waters with heavy metals in the Zyryanovsk deposit and Ridder town, revealed severe water contamination.

Influence of phenotypic and social traits on dispersal in a family living, tropical bird

Individual variation in natal dispersal behaviors has extensive ecological and evolutionary consequences. Traits such as offspring sex, age, and body condition may influence dispersal, resulting in a potentially complex suite of associations in traits that can affect fitness. Conceivably, individuals with particular phenotypes may breed in different habitats, thus potentiating the development of geographic variation. Moreover, studies typically underestimate dispersal distance owing to sampling issues and rarely consider the direction of movement, limiting understanding of this important life history stage. I examined the influence of phenotypic and social traits on dispersal distance and direction in a family living bird, the western slaty antshrike (Thamnophilus atrinucha). When accounting for detection probability, juveniles dispersed 1–14 territories and 46–1268 m. The age at dispersal and body mass upon leaving the nest influenced dispersal distance and direction. Older and heavier individuals dispersed shorter distances. Younger individuals dispersed towards comparatively younger forest with a higher density of antshrike territories. Older and heavier offspring may be more competitive and/or have increased experience with the local habitat, increasing their probability of acquiring nearby territories. Contrary to other studies, sex-biased dispersal distance was not observed. Instead, the sexes dispersed in different directions, potentially to reduce the risk of inbreeding. This study revealed the importance of age at dispersal and body mass on variation in dispersal behaviors and highlighted the need to investigate sex biases in dispersal direction. Key wor ds: baker method, family living, inbreeding avoidance, intraspecific competition, social species, tropical. [Behav Ecol]

High Apparent Annual Survival and Stable Territory Dynamics of Chestnut-Backed Antbird (Myrmeciza exsul) in a Large Costa Rican Rain Forest Preserve

Antbirds (Thamnophilidae) are a diverse component of neotropical forest avifaunas, and are particularly vulnerable to population declines and extirpations in fragmented landscapes. We lack estimates of apparent survival and dispersal for the majority of species, despite their value in effectively managing populations of understory birds. We studied a population of Chestnut-backed Antbird (Myrmeciza exsul) from 2004 to 2009 in a large rain forest preserve in northern Costa Rica to generate estimates of apparent annual survival (ϕ), and breeding dispersal (i.e., movement from one breeding territory to another) in continuous forest. Estimates of ϕ (± SE) of adults based on weighted model averages were high (males: 0.794 ± 0.037; females: 0.798 ± 0.050) compared to independent juveniles (males: 0.629 ± 0.159; females: 0.629 ± 0.168). Detection (recapture/reobservation) probabilities (p) were higher for males (adults: 0.916 ± 0.034; juveniles: 0.915 ± 0.049) than for females (adults: 0.544 ± 0.104; juveniles: 0.540 ± 0.115). Overall annual turnover (disappearing from the study area territory switching) was comparable to other antbirds (∼32%). Territory switching was rare, and generally limited to short movements to adjacent or nearby territories (mean distance moved = 372 m, range = 145–840 m, n = 9). Our results suggest Chestnut-backed Antbirds: (1) have relatively high adult annual survival, and (2) have limited breeding dispersal, even in a large, forested study area.

Pour une modélisation du cycle annuel de nomadisation des chasseurs-cueilleurs : données ethnographiques et conditions d’applications archéologiques

Changes in the social morphology of hunter-gatherer groups during their annual nomadic cycle can be reduced to three categories : a group in residential short or long-term camps (nomadic or semi-sedentary) ; an aggregate of several residential groups ; and the division of a residential group. Each of these categories refers to the organization of the group according to rules and socioeconomic standards unchanged by the departure or arrival of mere individuals. The residential group is made up of domestic units also forming interconnected domestic groups. It is materialized in the residential camp. The aggregate brings together residential groups exploiting the same territory or nearby territories. The aggregate camp is a place in which social and religious intensity is revealed, thus signalling that the residential groups belong to the same regional band. The phenomenon of division occurs when an age – and often a gender – group leaves the residential camp in order to supply it. This change in the sociological composition of the whole residential group turns the residential camp into a base camp. This third category of socioeconomic organization is thus materialized in two forms : the logistic expedition camp(s) of those who leave and in parallel a base camp. We shall illustrate these categories through three examples : Ammassalimiuts (Greenland), Nunamiuts (Alaska) and Akas (central Africa). In order to gain an archaeological perception of this phenomenon, we have to start with its materialisation. We then encounter two levels of analysis : the first is that of the different categories of settlement patterns corresponding to the sociological change and the second is that of production and consumption activities carried out in those settlements. In order to pass from the first level to the second, the settlement categories are compared with the availability of natural resources. Scattered nomadic residential groups would indicate easy access to plentiful and diversified resources ; logistic expeditions would point to the difficult acquisition of scattered game ; and, finally, the aggregate would not necessarily correspond to the exploitation of a located and plentiful resource, but would often occur during times of supply difficulties. While our categories do not thus belong exclusively to the economic domain, a possibility of apprehending them in terms of availability and exploitation of resource types nevertheless emerges. The possibility of bringing out tendencies by adopting a type of settlement according to the distribution of resources highlights the economic role of these settlements. The remains of operational sequences (“ chaîne opératoire ”) in the acquisition, treatment, consumption, preservation or transport of the resources found on a site allow the complementary nature of their economic links with other sites to be felt. Without taphonomic disturbances on a wide scale, intrasite spatial analysis, the type of structure recorded as well as their association with the distribution of remains, provides information about the location of activities, the contemporaneousness of the structures, their nature and their number. The aggregate and residential sites should show evidence of the daily activities of production and consumption. For the aggregate site, artefacts emblematic of social or symbolic activities should be expected. A logistic expedition site materializes the acquisition of a specific resource and its transport ; the resource may sometimes have been treated in order to facilitate its transport. The operational sequence of the activity started on the spot will be incomplete and will occur without any other types of activity. The typological discrimination then slips from the sociologic to the economic field, more within the reach of archaeology. However, even when there are not any important natural taphonomical disruptions, the determination of functions according to the site can be hindered for two reasons : the way the artefacts have been accumulated may involve a mixing of settlement patterns, and the disappearance of remains can go as far as the obliteration of some settlement categories.

The effect of vibrations in the Zhigulevskii Hydropower Structure on soils in the nearby territories of Tolyatti City

The Zhigulevskii Hydropower Structure is used as an example to study the vibration impact of a dam on the soils of the coastal zone in the upper and lower pools. The effect of vibration of the hydropower structure on soils composing the shore in the nearby territory was evaluated on the qualitative level. The analysis of seismic monitoring data allowed the authors to conclude that the specific features of the seismic regime of the territory both during spring releases and in dry period are governed by the regime of hydropower structure operation.

Solos, duets and choruses: vocal behaviour of the Rufous-naped Wren (Campylorhynchus rufinucha), a cooperatively breeding neotropical songbird

Vocal communication in duetting and chorusing birds is a growing area of study in avian ecology, yet much remains unknown about temporal and population-level variation in these complex vocal signals. In this study, we describe the acoustic structure and temporal variation in solos, duets, and choruses in the Rufous-naped Wren (Campylorhynchus rufinucha), a cooperatively breeding neotropical passerine. We collected focal recordings of 19 groups to assess both diel and seasonal variation in vocal output, as well as population-wide sharing of vocal signals. We found that birds produce a complex array of vocalisations, including tonal, frequency-modulated syllables grouped into phrases, as well as stereotyped, atonal sounds. Songs are produced as solos or combined into duets and choruses. Solo and duet songs show a dawn chorus effect. Solo song rate, but not duet or chorus rate, varied across breeding stages. The majority of phrases are shared amongst groups, significantly more amongst groups in nearby territories. We suggest that chorus songs may be an important indicator of group identity and may play a role in maintaining group territories, but do not play a role in relation to the breeding cycle. The degree of population-wide phrase-sharing suggests either short-distance dispersal or delayed song learning. This paper is the first fine-scale description of vocal behaviour in this species and enhances our understanding of group-singing in a complex social environment.

Parallel evolution of facial stripe patterns in the Neolamprologus brichardi/pulcher species complex endemic to Lake Tanganyika

Colour pattern diversity can be due to random processes or to natural or sexual selection. Consequently, similarities in colour patterns are not always correlated with common ancestry, but may result from convergent evolution under shared selection pressures or drift. Neolamprologus brichardi and Neolamprologus pulcher have been described as two distinct species based on differences in the arrangement of two dark bars on the operculum. Our study uses DNA sequences of the mitochondrial control region to show that relatedness of haplotypes disagrees with species assignment based on head colour pattern. This suggests repeated parallel evolution of particular stripe patterns. The complete lack of shared haplotypes between populations of the same or different phenotypes reflects strong philopatric behaviour, possibly induced by the cooperative breeding mode in which offspring remain in their natal territory and serve as helpers until they disperse to nearby territories or take over a breeding position. Concordant phylogeographic patterns between N. brichardi/N. pulcher populations and other rock-dwelling cichlids suggest that the same colonization routes have been taken by sympatric species and that these routes were affected by lake level fluctuations in the past.

Tesoro o monete sparse? A proposito di un gruzzolo di bronzi della zecca di Flavia Neapolis (Samaria)

In 1997 a hoard of 37 copper coins appeared on the antique market, coined in the mint of Flavia Neapolis and associated with the iconography of the temple of Zeus Hypsistos and of Mount Gerizim. Among the Emperors present on the coins: Elagabalus (25 coins), Alexander Severus (8 coins), Trebonianus Gallus (1 coin). Elagabalus’ group belongs to the light series; eleven of these specimens have a countermark used to establish a different and more valuable quota than the precedent, during Alexander Severus’ reign. Among the coins of this Emperor we can note two particularities. The first (cat. n. 32) concerns a legend of obverse, different to the ones known by the repertories. The second (cat. n. 33), due to its radiating head, allows us to recognize a new type of nominal and the probable formation of a relationship between two emissions in copper, similar to that between the dupondius and the as, found at that time in the western part of the empire. The coins of Flavia Neapolis, with the reverse side related to the Samaritan tradition, are coins that are highly sought after by collectors. It seems very unlikely therefore that such a numerous group of specimens could have been gathered and conserved for such a long period. By means of a comparison with similar coin findings in archaeological contexts it is hypothesized that the hoard was formed following a “thematic” selection of a larger treasure trove, probably discovered in Samaria or in the nearby territories, where it was hidden towards the first half of the 3rd century.

Fertilization success and UV ornamentation in blue tits Cyanistes caeruleus: correlational and experimental evidence

Cases where less ornamented males are favored through sexual selection are rare among birds. Here we show, based on data from 3 consecutive breeding seasons, that male blue tits with less ultraviolet (UV)-ornamented crown feathers sire more offspring. This pattern was mainly driven by the higher success of older, less UV-ornamented males at siring extrapair offspring. The reason behind this relationship is unclear although we hypothesize that being less UV-ornamented may enable adult males to intrude into nearby territories by mimicking juveniles. To test causality, we experimentally manipulated male crown coloration creating 2 groups, one with higher (UV(+) treatment) and one with lower UV reflectance (UV(−) treatment). Contrary to our expectations, UV(−) males were less likely to sire extrapair offspring than UV(+) males. The treatment had no effect on the likelihood of losing paternity in a male's own nest. Because the experimental evidence does not support the observational data, a direct effect of male crown color on extrapair success cannot be confirmed. However, potential pitfalls of this and other such color manipulation experiments, like fading of treatment with time and mismatches between behavior and coloration, call for new improved manipulation techniques and detailed behavioral observations to conclusively test for the effect of blue tit crown coloration on male extrapair success.

No Evidence of Current Sexual Selection on Sexually Dimorphic Traits in a Bird with High Variance in Mating Success

Sexual dimorphism, particularly in ornamental traits, is likely to have arisen by sexual selection. Most empirical and theoretical studies of sexual dimorphism assume that ongoing sexual selection also maintains the dimorphism. Over four seasons, I measured the sexual selection acting on three sexually dimorphic attributes (epaulet size, body size, and the blackness of the body plumage) of male red-winged blackbirds and found no consistent directional or stabilizing selection on any of them. Correlational selection was also negligible. I used path analysis to explore potential relationships in more detail but found no direct or indirect effects of male traits on either within- or extrapair success. Males who were resident on the marsh for more years had higher within-pair success, primarily because they spent more of the season on their territory. Experimental manipulations of epaulet size and color and the extent of nonblack feathers in the black body plumage had no detectable effect on the number of within-pair mates, paternity, or the number of extrapair offspring sired in nearby territories. These results combine with data from other studies of red-winged blackbirds to suggest that, despite high variation in male mating success and hence a strong opportunity for sexual selection, several morphological attributes that differ between the sexes and vary among males are not under current sexual selection. The possible explanations for why add complexity to our understanding of how sexual selection operates.

Home range and territory of the Sardinian Warbler Sylvia melanocephala in Mediterranean shrubland

Capsule Singing territories were well separated. Aims To examine the spatial distribution of Sardinian Warbler males during the breeding period in Mediterranean shrubland and, specifically, their territories, home ranges and spatial overlaps. Methods We studied a 12-ha plot of Mediterranean shrubland in the 1997 to 1999 breeding seasons. Sardinian Warblers were captured using mist-nets, colour-ringed and their territories mapped. In 1999, seven breeding males were radiotracked in order to map home ranges. Results The Sardinian Warbler had an average of 7.3 breeding pairs/10 ha in the study plot. The mean territory size was 8779 m2 and the mean home range was 22 321 m2. A positive relationship was found between the area of the home range and singing territory. Home ranges of males born in 1998 were about half the size of those of the oldest males. Paired males who moved with a female had smaller home ranges than those that were either unpaired or whose mate was incubating. The degree of home range overlap was high with some overlap between neighbouring territories. The estimate of home range area increased by 10% when the information generated by a mapping method was added and the estimated territory area increased by 31% when data generated by radiotracking were added. Transmitters remained attached to birds for an average of 9.63 ± 3.46 days (mean ± se). Conclusions Singing territories were segregated to a considerable degree. In contrast, the wide overlaps among home ranges was best explained by the presence of food resources that the males exploit at the same time and also by the search for extra-pair copulation in nearby territories. We consider radiotracking in this species to be feasible and valid, with no evidence of negative effects on activity levels, weight or mortality.

Breeding biology, adult survival and territoriality of the White-browed Treecreeper (Climacteris affinis) in north-west Victoria, Australia

This is the first study to present empirical data describing the social organisation and breeding biology of the White-browed Treecreeper (Climacteris affinis). The species is typical of many small Australian passerines in that it has high annual survival (∼80%), small clutches (mean = 1.95 ± 0.05), long breeding seasons (eggs laid August to November) and long incubation (17–18 days) and nestling periods (25–26 days), corrected for body weight. Reproductive effort is modified in response to variation in climatic conditions by adjusting the commencement of breeding and number of clutches laid per season, which is facilitated by an extended breeding season. White-browed Treecreepers occupied relatively large (mean = 8.4 ± 0.8 ha), all-purpose territories throughout the year. However, unlike many group territorial birds, territory size was not related to the number of occupants. The role of food limitation and climatic variability in relation to territory dispersion and life-history traits is explored. Facultative cooperative breeding was confirmed. Cooperative groups were formed through male philopatry, with usually only one, but up to three, male helpers present in a moderate fraction (35%) of breeding units. Thus, all species of Climacteris are now confirmed as facultative cooperatively breeding species, which provides further evidence for the aggregation of cooperative breeders at the generic level in mixed (i.e. cooperative and pair breeders) phylogenetic clades. In C. affinis, males may attain breeding positions through inheritance of their natal territory or by filling vacancies in nearby territories. Females obtained breeding positions by ‘floating’ as non-breeding residents in established territories, waiting for a vacancy to arise.

Extrapair Paternity Increases Variability in Male Reproductive Success in the Chestnut-Sided Warbler (Dendroica Pensylvanica), A Socially Monogamous Songbird

Abstract A monogamous mating system that includes extrapair fertilization can potentially generate higher variability in male reproductive success than monogamy without extrapair fertilization. That increased variability could provide a correspondingly higher opportunity for sexual selection and, thus, for the origin and persistence of sexual dimorphism in monogamous species. To determine whether extrapair fertilization enhanced the opportunity for sexual selection in a sexually dimorphic, monogamous bird species, we used microsatellite DNA typing to assess the prevalence of extrapair fertilization and its effect on variation in male reproductive success in a population of Chestnut-sided Warblers (Dendroica pensylvanica). We found that the level of extrapair fertilization in our study population was at the upper end of the range reported for bird populations (47% of nestlings had extrapair fathers; 61% of broods contained extrapair offspring). We also discovered that almost all extrapair offspring were sired by paired males resident on nearby territories. In addition, we found that variation in male reproductive success was substantially higher than variation in female reproductive success, and that extrapair fertilizations made a significant contribution to variation in male reproductive success. Together, those findings suggest that extrapair fertilization creates an opportunity for sexual selection on male traits in this population.

O estudo de prevalência de deficiências e incapacidades como instrumento de planejamento das atividades de atenção à saúde e reabilitação no Programa Saúde da Família

São parcos os estudos acerca de prevalência de deficiências e incapacidades na América Latina e no Brasil. Entre os poucos existentes temos os estudos multicêntricos de prevalência patrocinados pelo Ministério da Saúde em 11 municípios brasileiros, com metodologia proposta pela Organização Panamericana de Saúde (OPS). Esses estudos, fundamentados na Classificação Internacional de Deficiências, Incapacidades e Desvantagens (CIDID), apresentam dificuldades na sua aplicação e no planejamento de ações em territórios adscritos, pois são realizados por amostragem. O atual artigo apresenta dados da experiência do estudo de prevalência do PSF/Fundação Zerbini, na região Sudeste do município de São Paulo, com coleta censitária nas famílias cadastradas. A coleta foi realizada por agentes comunitários de saúde das equipes de família (médico, enfermeiro, auxiliar de enfermagem) e equipe de reabilitação (fisioterapeuta, fonoaudiólogo e terapeuta ocupacional) do território estudado, buscando-se dessa forma, uma relação íntima dos pesquisadores com a realidade retratada. A própria enquete está sendo utilizada como um instrumento dos profissionais no planejamento das ações preventivas e na assistência à população em saúde e reabilitação. Como objetivo geral, o estudo pretende estabelecer um diagnóstico complexo, relacionando dados de prevalência, da caracterização do território e dados referentes à exclusão social dessa população visando o planejamento de ações de intervenção.

Case studies in the conservation of biodiversity: degradation and threats

The rating of biodiversity in arid and semiarid regions on the basis of ecological function and genetic traits of adaptation to severe environmental stresses produces significantly higher values, than that based solely on the commonly applied structural criteria of forms of life and levels of organization. The indirect driving forces of biodiversity impoverishment listed in the Global Biodiversity Strategy that are particularly effective in arid and semi-arid regions are (a) population growth, (b) economic systems and policies that fail to value the environment and its natural resources; (c) inequity in the ownership, management and flow of benefits from both the use and conservation of biological resources; and (d) weakness in legal and institutional systems. The most effective direct human impacts are (a) habitat destruction and fragmentation, (b) overexploitation of biological resources, (c) biological invasion, and (d) agriculture. The problem in arid and semiarid regions, particularly in developing countries, is exacerbated by the lack of knowledge and awareness, the paucity of research, and the diminishing number of competent systematists. This paper discusses the theoretical and practical aspects of each of the indirect driving forces, and the direct human impacts on biodiversity, and reviews case studies related to these impacts, with special reference to those carried out in arid and semiarid regions. These studies include monitoring of the human impact on land cover by remote sensing, effects of landuse on species diversity, impact of habitat fragmentation by summer resorts on coastal dunes, consequences of protection from grazing on biodiversity, comparison of biodiversity in nature reserves and the traditional ema system with that of nearby territories, and the impact of desertification on animal life and endangered species. Case studies also include the tools applied for biodiversity conservation in arid and semiarid lands with special emphasis on endangered species, restoration of degraded habitats and their biodiversity, the significance of nature reserves and captive breeding, the importance of conserving the populations below the species level throughout their geographical range of distribution, and ecotonal biodiversity.

Microsatellite identification of extrapair sires in a socially monogamous warbler

Few studies of avian mating systems have identified the sires of extrapair young, and hence it has been difficult to determine the scale at which reproductive interactions occur. For instance, females may be free to copulate with any male in the population (a ‘‘global’’ scale of interactions), or females may be restricted to copulating only with males on neighboring territories (a ‘‘local’’ scale). The scale of such interactions has important consequences for an understanding of the evolutionary causes and consequences of extrapair fertilizations. We used five hypervariable microsatellite loci and multilocus DNA fingerprinting to examine parentage of more than 400 nestling black-throated blue warblers (Dendroica caerulescens). Extrapair fertilizations were common, and the microsatellite markers allowed us to identify the sires for 89% of the young analyzed. Most identified extrapair sires were males on neighboring or nearby territories, and most nestlings for whom we could not identify a sire came from territories at the edge of the study plot. Thus, reproductive interactions appear to be more local than global in this population. Extrapair fertilizations contributed significantly to total variation in male reproductive success. However, the standardized variance in male reproductive success (0.68–0.74) was not substantially greater than that for females (0.53–0.60), and the contribution of extrapair fertilizations (9–14%) was much lower than the contribution of within-pair fertilizations (75–77%). This suggests that the local scale of reproductive interactions may limit variation in male reproductive success and hence the opportunity for selection.

Breeding and Post-Breeding Habitat Use by Forest Migrant Songbirds in the Missouri Ozarks

Abstract We compared habitat use by forest migrant songbirds during the breeding and post-breeding periods in four Missouri Ozark habitats: mature upland forest, mature riparian forest, 9- to 10-year-old upland forest, and 3- to 4-year-old upland forest created by clearcutting. Adult forest-ground species showed a decrease in abundance in all habitats during the post-breeding period, but hatching-year birds of one of the two forest-ground species were most abundant in early-successional forest during this time. Adults of the two forest-canopy species tended to increase in abundance in 3- to 4-year-old forest from breeding season to post-breeding season. During the breeding season, some forest species were detected with mist-nets in the two early-successional habitats, but infrequently or not at all with point counts in those habitats. Forest birds captured in early-successional habitats during the breeding season may have been nonbreeding floaters, or may have been foraging there from nearby territories in mature forest. Dense shrubs or young trees in early-successional forest may provide habitat for nonbreeding and post-breeding forest migrant songbirds in the Missouri Ozarks.

BREEDING AND POST-BREEDING HABITAT USE BY FOREST MIGRANT SONGBIRDS IN THE MISSOURI OZARKS

Abstract We compared habitat use by forest migrant songbirds during the breeding and post-breeding periods in four Missouri Ozark habitats: mature upland forest, mature riparian forest, 9- to 10-year-old upland forest, and 3- to 4-year-old upland forest created by clearcutting. Adult forest-ground species showed a decrease in abundance in all habitats during the post-breeding period, but hatching-year birds of one of the two forest-ground species were most abundant in early-successional forest during this time. Adults of the two forest-canopy species tended to increase in abundance in 3- to 4-year-old forest from breeding season to post-breeding season. During the breeding season, some forest species were detected with mist-nets in the two early-successional habitats, but infrequently or not at all with point counts in those habitats. Forest birds captured in early-successional habitats during the breeding season may have been nonbreeding floaters, or may have been foraging there from nearby territories i...

Use of Space by Nesting Black-billed GullsLarus bulleri: Behavioural Changes During the Reproductive Cycle

Black-billed Gulls Larus bulleri nesting in seven colonies in braided rivers in New Zealand were studied in 1990. These habitats are subject to frequent floods following heavy rain or snow melts. While a colony contained only incubating birds, the gulls nested close together (mean nearest neighbour distance 45-80 cm in six colonies) but once chicks began to hatch and to wander into nearby territories, families required more space. Parents and families moved outside the original colony and, eventually, to the water's edge. Aggression levels were low for incubating birds, increased for parents with chicks still in the colony and decreased when parents with their chicks moved to the water's edge. Parents with territories at the water's edge benefitted from increased space, lower aggression rates, and decreased food piracy while they were feeding their chicks. For chicks, the advantages were decreased aggression from neighbours and the ability to escape to the water when a ground or aerial predator approached.

Tactic for bower acquisition by male cichlids,Cyathopharynx furcifer, in Lake Tanganyika

A tactic for bower acquisition by male cichlids,Cyathopharynx furcifer, was studied in Lake Tanganyika. Males held crater-shaped bowers of sand within their territories, which were located adjacent to each other. Females visited bowers to spawn eggs, subsequently brooding the eggs in their mouths. Some individuals held territories without bowers near those of males with bowers. Although only the males with bowers succeeded in reproduction, they were apparently exhausted by bower maintenance and reproduction, and often deserted their bowers. These were soon occupied by males which had held nearby territories without bowers, such males then engaging in reproductive activity. Although the construction of new bowers by males was observed, such was unsuccessful, probably because too much energy was required and/or the optimal space for bowers was limited. Direct aggression by males without bowers against bower-holding males to deprive the bowers was not observed, possibly due to the high costs of such competition. Therefore, waiting for bower desertion by other males may be the best bower acquisition tactic for males without bowers.