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Barnett, Denise; Kemp, Nan

doi:10.1007/978-1-4899-7100-5_19

Cited by 3 publications

(9 citation statements)

References 2 publications

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“…Mortality and injury in these colonies, regardless of their particular constitution or history, was almost confined to males (cf. Barnett, 1951). I n the whole series of experiments ( Table 1) only five female R. norvegicus died : one died from no known cause in each of experiments 2, 5, and 34 ; the other two were newcomers to colony 18 and were killed by a male which behaved atypically (section 9.4).…”

Section: In Undisturbed Coloniesmentioning

confidence: 98%

“…In some instances, after the rats were weighed at the end of the main part of the experiment, some or all were returned to the cage for further study, in particular of the effects of the introduction of strange rats. I n other instances the male rats were killed and their adrenal and thyroid glands were removed ; observations on these organs are reported separately (Barnett 1958(Barnett , 1958a.…”

Section: The Ratsmentioning

confidence: 99%

“…The building was quiet at these times and the rats were active. All the main types of adult behaviour observed were filmed (Barnett, b, 1956 c), sometimes at high speed so that movements could be studied in slow Water was provided in inverted bottles. motion.…”

Section: The Cages and Coloniesmentioning

confidence: 99%

“…Detailed observations of behaviour have not been described. Barnett (1951) found that adult rats, previously strangers to each other, when placed in an unfamiliar enclosure, showed a high initial mortality, even in the presence of a great excess of cereal food. Deaths occurred principally among the males, and after a few weeks few males remained.…”

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confidence: 98%

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An Analysis of Social Behaviour in Wild Rats

Barnett

1958

Proceedings of the Zoological Society of London

210

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SUMMARY Wild rats (Battus norvegicus Berkenhout and R. rattus L.) were kept in large cages fitted with nest boxes and supplied with excess food and water. Colonies varied in size from four to twenty rats, and were usually maintained for at least nine weeks. The rats were individually identified and their behaviour studied in detail. Rattus norvegicus. In all‐male colonies there was a low mortality and most of the rats increased in weight. In colonies containing both males and females, mortality was high among the males, very low among the females; most of the males declined in weight, though some grew well. There was however no fighting for females. It is suggested that the extra fighting which took place in these colonies resembled displacement behaviour and was due to excitement evoked by the presence of females combined with frequent frustration. There were no deaths in all‐female colonies, or in colonies of litter mates. Unless parturient, normal females did not display aggressive behaviour except in ‘play’. Males, but not females, added to established colonies, were attacked by resident males and usually died, sometimes within a few hours and often without visible injury. At the beginning of an experiment there was much exploration, both of the cage and of the other rats. Social relationships were established early. Male members of the colonies fell into three classes: (i) alphas, which were the equals or superiors of other males in the colony, and attacked newcomers; (ii) betas, which adapted themselves to a subordinate role, and were ingratiating towards newcomers; (iii) omegas, which were persecuted by one or more alphas and soon died. Alphas and betas gained in weight; omegas lost weight. There were more omegas in male‐female colonies than in those consisting only of males. Amicable behaviour (apart from coitus and care of young) was shown by both sexes and was based mainly on contact ‘releasing’ stimuli: the most specific of a number of amicable responses was crawling under the belly of another rat. Fighting involved a series of stereotyped acts, including tooth chattering and a characteristic threat posture; there was much wild leaping, but biting produced only superficial damage. Rattus rattus. A small number of experiments with R. rattus showed that this species possesses all the components of amicable and aggressive behaviour observed in R. norvegicus, but that it is less fierce and more agile. There was no evidence of extra conflict in male‐female colonies. All‐male colonies containing both species were usually peaceful. R. rattus of either sex added to norvegicus colonies were usually attacked, but not with such intensity or consistency as were male norvegicus; if attacked, they died. R. norvegicus males added to rattus colonies were sometimes attacked, but they did not die. Displacement behaviour and abnormaľ sexual and aggressive behaviour were observed in both species. General. There is no reason to think that dominance hierarchies ever develop in wild rat colonies. Members of a single famil...

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Section: In Undisturbed Coloniesmentioning

confidence: 98%

Section: The Ratsmentioning

confidence: 99%

Section: The Cages and Coloniesmentioning

confidence: 99%

mentioning

confidence: 98%

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An Analysis of Social Behaviour in Wild Rats

Barnett

1958

Proceedings of the Zoological Society of London

210

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“…Finally, both mechanisms might not only affect the reproductive rate but also the survival of the adult birds themselves. The restless behaviour of the non-breeding population, arising from the fact that they are chased continuously by territory-holding birds, may produce the so-called Selye stress syndrome (Barnett 1958), with an increased mortality rate in both breeding and non-breeding individuals. The emigration to sub-optimal habitats may also affect the mortality rate of adults due, for example, to lack of adequate food or to insufficient cover from predators, etc., two factors which might besides also affect the non-breeding birds (cf.…”

Section: Iris 107mentioning

confidence: 99%

A POPULATION STUDY OF SKYLARKS ALAUDA ARVENSIS

Delius¹

1965

Ibis

123

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SUMMARY A population of colour‐ringed Skylarks Alauda arvensis was studied intensely over two and less thoroughly over another five breeding seasons in Kavenglass, Cumberland. The breeding season extends from mid‐April to early July, but the onset, which is well synchronized, varies from year to year, probably depending on the spring temperature. One‐year‐olds lay the first clutch about a week later than older birds. Within a group of females there is a constancy in the laying order of first clutches from year to year. The rank of any given female seems to depend on an individual temperature threshold, which is reached four to seven days before laying, but other factors must play a role. The interval between the disappearance of a clutch or brood and the laying of the next clutch varies from four to six days depending on the stage at which the previous brood was lost. Beyond the 17th or 18th day of life the chicks of one brood no longer prevent the laying of a new clutch. No factors influencing the end of the season could be found. On average, Skylarks lay 2.7 clutches per year (range 1–5). Three successful broods seems to be the maximum. Average c/size is 3.69 eggs (range 3–5). The c/size varies with successive clutches, from 3.3 for first, to 4.0 for third clutches. Individual females tend to lay clutches of a characteristic size. No difference could be found between the clutches of one‐year and older birds, Females which retain the same territory from year to year show more consistency in clutch size than those which change territories. Data from different geographical locations in Europe suggest a cline from northwest to southeast of increasing clutch size. Clutch size does not seem to be affected by temperature. The variability of egg size and shape is discussed. 68% of the eggs laid hatched (incubation period 11 days) and 67% of the young hatched left the nest on the 8th day. About 90% of the eggs and young lost were taken by predators. No consistent seasonal differences in nest mortality could be found, nor between c/3 and c/4. An incidental experiment suggests that predation of Skylark nests is density dependent. The success of one‐year‐old females in rearing nest‐leaving young is lower than that of older birds (15% compared with 51%). From observations of the feeding behaviour of the parents it is estimated that about 25% of the young survived to flying age (16th day of life), and about 10% reached independence (30th day). Skylarks, males more than females, exhibit a strong site‐tenacity. One‐year‐old birds tend to return to the birthplace area. Associated with site‐tenacity the Skylarks show mate‐faithfulness. Of 36 pairs 17 remained faithful from one year to the next. During a breeding season mate‐faithfulness is practically absolute. There is a correlation between the breeding success of a pair and the likelihood of the pair remaining together the following year. Mean annual adult mortality was 33.5%, with little variation except in 1962/63 (47%‐the result of a hard winter). After reaching independenc...

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Evaluación del impacto ambiental del cultivo de la pitahaya, Cantón Palora, Ecuador

Diéguez-Santana

Zabala-Velin

Villarroel-Quijano

et al. 2020

TecnoL.

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La fruta pitahaya (Selenicereus megalanthus) es una fruta subtropical exótica con piel amarilla, de pulpa con sabor agridulce, que contiene niveles de ácidos grasos esenciales como los ácidos oleico y linoleico. Su cultivo, en los últimos años, se ha convertido en una de las principales actividades económicas de la provincia Morona-Santiago. El objetivo de este trabajo fue determinar el impacto ambiental que genera el cultivo de pitahaya, y proponer estrategias de manejo que permitan mitigar los efectos sobre el medio ambiente. Se realizó la caracterización de los medios físico, biótico, socioeconómico y cultural de plantaciones del Cantón Palora, según los criterios de las normativas ambientales nacionales. La metodología empleada estuvo conformada por el uso de: listas de chequeo y la matriz de Leopold, las cuales se fundamentan en el análisis de las interacciones existentes entre las etapas del cultivo y los factores ambientales impactados. Los principales resultados en la finca evaluada muestran impactos negativos como la pérdida de biodiversidad, degradación de suelos, del medio físico, asociados principalmente por el uso de agroquímicos, el desbroce de ecosistemas boscosos, así como la apertura de caminos de acceso. El plan de manejo muestra estrategias encaminadas a mitigar y compensar los impactos más severos, y dar cumplimiento a las leyes ambientales vigentes.

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S

Cited by 3 publications

References 2 publications

An Analysis of Social Behaviour in Wild Rats

An Analysis of Social Behaviour in Wild Rats

A POPULATION STUDY OF SKYLARKS ALAUDA ARVENSIS

Evaluación del impacto ambiental del cultivo de la pitahaya, Cantón Palora, Ecuador

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