Demography of a ground nesting bird in an urban system: are populations self-sustaining?

Urbanization poses threats to earth’s biota, and retention of remnant native habitat in protected areas within expanding urban boundaries may help alleviate threats to wildlife. However, it is unclear for nearly all nonsynanthropic (i.e., not benefiting from an association with humans) species whether vital rates in urban habitats can sustain populations or if populations persist only through immigration from outside the urban boundary. We conducted a three-year study of spotted towhees (Aves: Pipilo maculatus) breeding in four undeveloped parks in Portland, OR, USA, to measure park-specific seasonal reproductive output (F) and annual adult survival (S_A). We developed a stochastic model that combined F and S_A with an estimate of first-year survival to measure population growth rate (λ) in all parks assumed to be closed to immigration. F differed among parks but S_A did not. Relatively high F was possible because many pairs raised >1 brood/season. When combined with empirical estimates of survival through the 30-day period of post-fledging parental care (S_D = 0.645), only 2 of 4 parks were self-sustaining (i.e., λ > 1.0). However, S_D reflected substantial loss of fledglings to domestic cats (Felis catus). Assuming no loss to cats and either partial compensatory or additive mortality of fledglings substantially improved prospects of population persistence for declining (sink) populations. Moreover, allowing low levels of immigration to sinks reversed population declines in most parks even when vital rates were insufficient to maintain populations. Our results suggest that nonsynanthropic bird species can persist in urban landscapes, but also that offspring mortality in the post-fledging period may be a critical determinant of population viability.     

Assessing the diversity of the benthic oligochaete communities in urban and woodland ponds in an industrial landscape (Upper Silesia,southern Poland)

Studies were carried out in two mining pond complexes in an industrial landscape. The first complex (consisting of six ponds) was located in an urban area and the second one (consisting of six ponds) in a woodland area. The aims of the study were to assess the diversity of benthic oligochaetes and to evaluate which environmental variables are most important in determining variations in the community structure in ponds of varying location. In total, 21 oligochaete species were recorded (7–11 in the urban ponds, 11–15 in the woodland ponds). Aulodrilus pluriseta, Aulodrilus japonicus and Ophidonais serpentina were only found in the woodland ponds, while Potamothrix bavaricus only occurred in the urban ponds. Limnodrilus hoffmeisteri, Limnodrilus claparedeanus, Chaetogaster diaphanus and Ophidonais serpentina dominated in the woodland ponds, whereas Limnodrilus hoffmeisteri, Limnodrilus claparedeanus, Potamothrix bavaricus and Tubifex tubifex prevailed in the urban ponds. The total density of oligochaetes was higher in the urban ponds thought the values of the diversity indices were higher in the woodland ponds. The local diversity of the ponds was high, while the among-site diversity made only a small contribution to the regional diversity. Nonetheless, a cluster analysis divided all of the ponds into two distinct groups depending on their location. CCA analysis showed that conductivity, pH, total hardness, alkalinity, the concentration of chlorides and the content of organic matter in the bottom sediments were most associated with the distribution of some oligochaete species among the ponds studied.     

Does urbanization affect the seasonal dynamics of bird communities in urban parks?

The environmental factors affecting the spatial dynamics of bird communities in urban parks are well understood, but much less attention has been paid to the seasonal dynamics of bird communities. Since migrant and resident human commensal birds might have contrasting responses to environmental factors of urban parks, we expected different seasonal dynamics among parks. On the other hand, because bird species can have different habitat relationships throughout the year, we also expected different responses of bird richness to environmental variables between breeding and non-breeding seasons. Bird surveys were conducted in 14 small urban parks (1–4 Ha) of Mar del Plata city (Argentina) for one full annual cycle. Bird richness changed between seasons, but bird abundance remained constant. Bird community composition did not vary between seasons, but urban parks near the urban center, with the highest pedestrian traffic and isolation to other green areas had the least seasonal change of composition. During the breeding season, bird richness was negatively affected by the percentage cover of high buildings surrounding the immediate limits of parks, whereas during the non-breeding season bird richness was not related with any environmental variable. Bird composition variation among parks was affected by the distance to the urban center during both seasons. Results showed that urbanization promotes a seasonal homogenization of bird communities in urban parks, probably by affecting the presence of migrant species and promoting the temporal stability of human commensal species.     

Social Skills in Children Adopted From Socially-Emotionally Depriving Institutions

This study assessed social skills in post-institutionalized (PI) children with respect to age at adoption, age at assessment, and gender. Parent ratings of social skills (Social Skills Rating System) and behavior problems (Child Behavior Checklist) were obtained for 214 children and 127 adolescents who were adopted from socially-emotionally depriving Russian institutions. Results showed that children adopted before 18 months of age have better social skills than those adopted after this age; those assessed in childhood demonstrate better social skills than those assessed in adolescence. PI females, especially later-adopted adolescents, have particularly poor social skills. Children with poor social skills tend to have higher rates of behavior problems.     

Fighting words? Joning as conflict talk and identity performance among African American preadolescents

This study examines how preadolescent African American students in Washington, D.C., used a linguistic practice called ‘joning,’ a style of verbal play similar to ritual insults, in peer interactions. Sociolinguists have focused on how children socialize each other into vernacular styles appropriate for peer group use but often assume that they disalign with social and linguistic norms for classroom behavior. Drawing from a nine‐month ethnographic study that the author conducted in an after‐school program, this article analyzes the structure and function of joning as a vernacular style of African American Vernacular English and its uses in constructing classroom identities. Joning often facilitated student learning, but it was perceived as a socially and physically risky linguistic practice because of its uses as conflict talk in the local community. Focusing on preadolescence as a key stage of language socialization, this article shows how minority students modify peer‐learned linguistic practices to pursue academic success on their own terms.     

Wiki-worthy: collective judgment of candidate notability

The use of socio-technical data to predict elections is a growing research area. We argue that election prediction research suffers from under-specified theoretical models that do not properly distinguish between ‘poll-like’ and ‘prediction market-like’ mechanisms understand findings. More specifically, we argue that, in systems with strong norms and reputational feedback mechanisms, individuals have market-like incentives to bias content creation toward candidates they expect will win. We provide evidence for the merits of this approach using the creation of Wikipedia pages for candidates in the 2010 US and UK national legislative elections. We find that Wikipedia editors are more likely to create Wikipedia pages for challengers who have a better chance of defeating their incumbent opponent and that the timing of these page creations coincides with periods when collective expectations for the candidate's success are relatively high.