Adoption or infanticide: options of replacement males in the European starling

The behaviour of a male bird towards a potential mate and her clutch may depend both on his expected paternity and on the likelihood that she will produce a replacement clutch if he commits infanticide. In this study we evaluate the choices made by replacement male European starlings Sturnus vulgaris. By removing males before and during laying, we induced other males, mainly neighbours, to mate with the reproductively active females. When the original male was removed before laying, a new male adopted the subsequent clutch in 14 out of 15 cases. When ten females were widowed during their laying period, replacement males never adopted their clutches. The paternity of replacement males was a function of when they replaced the former male. When replacement occurred more than 3 days before egglaying, the new male fathered nearly all offspring; when it occurred the day before laying, the new male still fathered more than every second young. When the original male was removed during his mate’s laying period, in five out of ten cases a replacement male committed infanticide by throwing out the eggs, but this only occurred in one out of 15 cases when removal took place before laying. The evidence for infanticide actually being committed by the replacement male was circumstantial. Four out of six of the females affected by apparent infanticide produced replacement clutches in which the male presumably had higher paternity than in the original clutch. In all cases, the male adopted the replacement clutch. In five cases when the original male was removed during laying, the neighbours neither adopted the brood nor committed infanticide, although they sometimes were seen courting the widowed female and copulating with her. These cases occurred later during laying than those were males comitted infanticide. The time from infanticide to the laying of the replacement clutch tended to increase as infanticide was committed later in the laying sequence. We conclude that strategies of potential replacement males are influenced by their expected paternity in the current brood and the probability that the female will produce an early replacement clutch. Received: 10 March 1995 / Accepted after revision: 28 October 1995     

Chemical and biological characterization of emissions from small residential stoves burning wood and charcoal

Emissions from a small residential wood stove and a newly developed residential stove burning charcoal have been characterized by chemical analysis and mutagenicity testing (Ames Salmonella test). For wood burning the samples were taken under normal and starved air conditions burning birch and spruce separately. The burning conditions in the stove seemed to influence the emissions to a larger extent than the type of wood.The emissions of aldehydes, benzene and polycyclic aromatic hydrocarbons from the charcoal-burning stove are lower by a factor of 25–1000 as compared to the wood stove. The mutagenicity of the emissions showed a similar trend.     

Evolution of variation in male secondary sexual characteristics

Summary The male pied flycatcher Ficedula hypoleuca exhibits sexual dimorphism in its plumage colour, varying from a female-like brown to jet black. The evoltution of this variation in male plumage colour can be explained by at least eight hypotheses viz., (I) neutral mutation; (II) individual recognition; (III) three forms of inter-sexual selection; (IIIa) mate selection for phenotypes, (IIIb) Fisherian selection, (IIIc) handicap selection; (IV) intrasexual selection; (V) delayed maturation; and (VI) female mimicry. The assumptions and predictions derived from all these hypotheses were tested by analysing the observed variation in male plumage colour in relation to age, body size, physical condition, survival rate, aggressivity in territorial defence, territorial quality, female choice of mate, sex ratio, and reproductive success. We found that: males became blacker with age; black males were larger than browner ones; however, browner males survived better between breeding seasons than did blacker ones; black males were more aggressive against black than brown intruders; blacker males occupied better territories; blacker males were paired earlier than browner males; and finally blacker males produced heavier offspring than did brown males. A reasonable conclusion from the results of these analyses is that four of the hypotheses considered, viz. mate selection for phenotypes (IIIa), Fisherian selection (IIIb), handicap selection (IIIc), and intra-sexual selection (IV) could not be rejected. We therefore suggest that the evolution of the observed variation in the secondary sexual characteristics of the male pied flycatcher can be explained by a combination of these hypotheses.     

The role of risk perception and other risk-related judgements in transportation mode use

AimsThe core aim of the present study was to examine the role of risk perception in use of private and public modes of transportation. An additional aim was to examine the relative importance of perception of transport risks with risk perception of non-transport factors and also to investigate differences in worry, perceived control of transportation modes, as well as trust in authorities’ risk handling, safety motivation, and attitudes towards transport safety.SampleThe results are based on a mailed self-completion questionnaire survey carried out among a representative sample of the Norwegian public aged from 18 to 65 years (n = 1864). Data collection was carried out during October–December 2008.ResultsPerceived control related to private modes of transportation, knowledge about safety and trust in authorities were found to be significantly different among respondents who often used private modes of transportation compared to those who most often used public modes. It was no significant difference in severity of consequences due to which transport modes that the respondents used most frequently.ConclusionIt may be that conclusions of previous research about the role of consequence judgement for precautionary action and demand for risk reduction are misleading when generalised to decisions about transport mode use.     

ISO 14001 in environmental supply chain practices

This paper focuses on the role of ISO 14001 in environmental supply management practices in Swedish companies. It discusses the existing and potential role of ISO 14001 for three key operational tasks of environmental supply chain management: to communicate the requirements to the supplier, to motivate and enable the supplier, and to verify that the supplier follows the requirements. The study used three different research methods: interviews with environmental managers, focus group discussions and a survey of two multinational companies and their operating units in several countries.It concludes that cooperation between the purchasing and environmental functions within a company is frequently not sufficiently achieved in implementation of ISO 14001; this makes the communication of customer requirements to suppliers less efficient. Building close relationships with suppliers is important to overcome initial difficulties, but this often conflicts with having a large supplier base. For the supplier to have an ISO 14001 certificate is seldom an absolute requirement, however, preference is often given to such suppliers. The value of the ISO 14001 certificate, as a proof of environmental performance, is a combination of the supplier's environmental ambitions, the advancement of supply chain practices of the customer and the ambitions of the certification bodies. Supplier audits are not commonly used as they are resource-consuming. Monitoring and verification approaches need further development.     

Differences in risk perception,priorities, worry and demand for risk mitigation in transport among Norwegians in 2004 and 2008

The present study aimed to investigate differences in risk perception, the demand for risk mitigation, priorities and worry related to transport among the Norwegian public in 2004 and 2008. Age, gender, education, driver licence and number of injuries in transport were controlled for. The comparison was carried out with questionnaire surveys among representative samples of the Norwegian public in 2004 (n = 1730) and 2008 (n = 1864). The results showed that the perceived probabilities of transport accidents decreased, whereas the perceived severity of consequences increased during this period. Both samples estimated higher probabilities of accidents by private means of transport. The demand for risk mitigation and priorities related to transport safety increased significantly in the same period. The 2008 sample also reported more worry regarding accidents by private transport. Results were discussed in relation to transport safety campaigns, safety measures and significant accidents which occurred in this period.     

Association of reproductive traits with captive- versus wild-sourced birds in trade

The wildlife trade is a billion-dollar global business, involving millions of people, thousands of species, and hundreds of millions of individual organisms. Unravelling whether trade targets reproductively distinct species and whether this preference varies between captive- and wild-sourced species is a crucial question. We used a comprehensive list of all bird species traded, trade listings and records kept in compliance with the Convention on International Trade in Endangered Species (CITES), and a suite of avian reproductive parameters to examine whether wildlife trade is associated with particular facets of life history and to examine the association between life-history traits and captive- and wild-sourced traded volumes over time. Across all trade, CITES listing, and CITES trade, large birds were more likely to be traded and listed, but their longevity and age at maturity were not associated with CITES listing or trade. We found species across almost the full range of trait values in both captive and wild trade between 2000 and 2020. Captive trade volumes clearly associated with relatively longer lived and early-maturing species; these associations remained stable and largely unchanged over time. Trait–volume associations in wild-sourced trade were more uncertain. Only body mass had a clear association, and it varied from negative to positive over time. Although reproductive traits were important in captive-sourced trade, species-level variation dominated trade, with even congeneric species varying greatly in volume despite similar traits. The collection and incorporation of trait data into sustainability assessments of captive breeding facilities are crucial to ensure accurate quotas and guard against laundering.     

Brood sex ratios, female harem status and resources for nestling provisioning in the great reed warbler (Acrocephalus arundinaceus)

The theory of parental investment and brood sex ratio manipulation predicts that parents should invest in the more costly sex during conditions when resources are abundant. In the polygynous great reed warbler, Acrocephalus arundinaceus, females of primary harem status have more resources for nestling provisioning than secondary females, because polygynous males predominantly assist the primary female whereas the secondary female has to feed her young alone. Sons weigh significantly more than daughters, and are hence likely to be the more costly sex. In the present study, we measured the brood sex ratio when the chicks were 9 days old, i.e. the fledging sex ratio. As expected from theory, we found that female great reed warblers of primary status had a higher proportion of sons in their broods than females of lower (secondary) harem status. This pattern is in accordance with the results from two other species of marsh-nesting polygynous birds, the oriental reed warbler, Acrocephalus orientalis, and the yellow-headed blackbird Xanthocephalus xanthocephalus. As in the oriental reed warbler, we found that great reed warbler males increased their share of parental care as the proportion of sons in the brood increased. We did not find any difference in fitness of sons and daughters raised in primary and secondary nests. The occurrence of adaptive sex ratio manipulations in birds has been questioned, and it is therefore important that three studies of polygynous bird species, including our own, have demonstrated the same pattern of a male-biased offspring sex ratio in primary compared with secondary nests. Received: 1 June 1999 / Received in revised form: 10 January 2000 / Accepted: 12 February 2000     

Effect of scale on trait predictors of species responses to agriculture

Species persistence in human‐altered landscapes can depend on factors operating at multiple spatial scales. To understand anthropogenic impacts on biodiversity, it is useful to examine relationships between species traits and their responses to land‐use change. A key knowledge gap concerns whether these relationships vary depending on the scale of response under consideration. We examined how local‐ and large‐scale habitat variables influence the occupancy dynamics of a bird community in cloud forest zones in the Colombian Chocó‐Andes. Using data collected across a continuum of forest and agriculture, we examined which traits best predict species responses to local variation in farmland and which traits best predict species responses to isolation from contiguous forest. Global range size was a strong predictor of species responses to agriculture at both scales; widespread species were less likely to decline as local habitat cover decreased and as distance from forest increased. Habitat specialization was a strong predictor of species responses only at the local scale. Open‐habitat species were particularly likely to increase as pasture increased, but they were relatively insensitive to variation in distance to forest. Foraging plasticity and flocking behavior were strong predictors of species responses to distance from forest, but not their responses to local habitat. Species with lower plasticity in foraging behaviors and obligate flock‐following species were more likely to decline as distance from contiguous forest increased. For species exhibiting these latter traits, persistence in tropical landscapes may depend on the protection of larger contiguous blocks of forest, rather than the integration of smaller‐scale woodland areas within farmland. Species listed as threatened or near threatened on the International Union for Conservation of Nature Red List were also more likely to decline in response to both local habitat quality and isolation from forest relative to least‐concern species, underlining the importance of contiguous forests for threatened taxa.