Nestling begging strategies in Wilson's storm-petrels (Oceanites oceanicus): insights from a supplementary feeding experiment

Whether parents or their dependent offspring control provisioning and how resource allocation is mediated behaviourally are fundamental questions in the context of parent – offspring conflict. Vocalisations during feeding of chicks of a small long-lived seabird, the Wilson’s storm-petrel (Oceanites oceanicus), were recorded on King George Island, maritime Antarctic, to evaluate their information content and effects on regulating provisioning by the attending adult. A supplemental feeding experiment was conducted in order to verify empirical findings. During the control period chicks honestly signalled their nutritional need, they conveyed information about their body condition through the number and sound frequency of begging calls uttered during feeding sessions. Parents were responsive to the information communicated through solicitation behaviour and delivered larger meals to nestlings in a poorer state but within a certain range under the constraints of food availability. Adults attending artificial fed nestlings increased delivered meal sizes by 2 g, which equals one third of a usual feeding, as response to intensified begging of their supplemented chicks

Data from: Sleepless in town – drivers of the temporal shift in dawn song in urban European Blackbirds

Organisms living in urban environments are exposed to different environmental conditions compared to their rural conspecifics. Especially anthropogenic noise and artificial night light are closely linked to urbanization and pose new challenges to urban species. Songbirds are particularly affected by these factors, because they rely on the spread of acoustic information and adjust their behaviour to the rhythm of night and day, e.g. time their dawn song according to changing light intensities. Our aim was to clarify the specific contributions of artificial night light and traffic noise on the timing of dawn song of urban European Blackbirds (Turdus merula). We investigated the onset of blackbird dawn song along a steep urban gradient ranging from an urban forest to the city centre of Leipzig, Germany. This gradient of anthropogenic noise and artificial night light was reflected in the timing of dawn song. In the city centre, blackbirds started their dawn song up to 5 hours earlier compared to those in semi-natural habitats. We found traffic noise to be the driving factor of the shift of dawn song into true night, although it was not completely separable from the effects of ambient night light. We additionally included meteorological conditions into the analysis and found an effect on the song onset. Cloudy and cold weather delayed the onset, but cloud cover was assumed to reflect night light emissions, thus, amplified sky luminance and increased the effect of artificial night light. Beside these temporal effects, we also found differences in the spatial autocorrelation of dawn song onset showing a much higher variability in noisy city areas than in rural parks and forests. These findings indicate that urban hazards such as ambient noise and light pollution show a manifold interference with naturally evolved cycles and have significant effects on the activity patterns of urban blackbirds

Model selection results for the subsets and full dataset examining the influence of anthropogenic noise, artificial night light and weather components on the onset of blackbird dawn song.

<p>All models contain a correction factor for spatial autocorrelation and a random intercept to account for repeated measures of individual birds.</p>a<p>Noi – PCA factor noise, Ld – lamp density, Day – Julian date, Temp – temperature, Cloud – cloud cover, Moon – lunar phase; Habitat – habitat factor.</p><p>Model selection was based on Akaike’s information criteria (AIC). The parameter <i>df</i> indicates the residual degrees of freedom, <i>K</i> represents the number of parameters in the candidate model and ΔAIC the difference of AIC values to the top-ranking model. Only candidate models with ΔAIC <4 are presented, because they are considered to receive support, and included to calculate Akaike weights (<i>ω_i</i>).</p

Parameter estimates for the influence of explanatory variables on the onset of blackbird dawn song.

<p>The panels illustrate the best models of the (A) overall data set and (B) park/forest and city centre subsets. Negative values indicate an advancing effect on the song onset, positive values a delaying effect. Only explanatory variables included in the best models are shown here. Asterisks represent the levels of significance for the explanatory variables as follows ***P<0.001, **P<0.01, *P<0.05.</p

Onset of blackbird dawn song along an urbanisation gradient.

<p>If the notches of two boxes do not overlap it is strong evidence that their medians differ.</p

Number of blackbird song posts at the different study sites.

<p>Number of blackbird song posts at the different study sites.</p

Study area in Leipzig with artificial night light (A), noise from car traffic (B) and tramways (C).

<p>(<b>A</b>) represents the study area with its different sites (C1–P6). In the northeast of the study area are the inner city centre (C4) with adjacent tiny parks (C1) and green spaces (C2) and an urban fallow area (C3). To the southwest follows a series of public parks of different sizes (P2– P6) and the urban forest (P1). The whole study area covers 215 ha. The black and white points indicate blackbird song posts in the two seasons 2011 and 2012, respectively. One bird can use more than one song post. The inlay in (A) illustrates the street light densities of the study area and its close vicinity. Noise levels for car traffic (B) and tramways (C) at night are shown for the same area. Noise levels above 60 dB(A) are indicated by orange and red colour.</p

Proposed influence of anthropogenic noise and artificial night light on the song onset of blackbirds.

<p>The smoothing function of anthropogenic noise (here derived from the PCA-factor noise) is a linearly increasing effect on the song onset of blackbirds, whereas the smoothing function of artificial night light (street lamps per ha) approximates an asymptote. The smoothing functions are plotted with the 95% Confidence Interval.</p

Environmental monitoring and management proposals for the Fildes Region, King George Island, Antarctica

The Antarctic terrestrial environment is under increasing pressure from human activities. The Fildes Region is characterized by high biodiversity, but is also a major logistic centre for the northern Antarctic Peninsula. Different interests, from scientific research, nature conservation, protection of geological and historical values, station operations, transport logistics and tourism, regularly overlap in space and time. This has led to increasing conflict among the multiple uses of the region and breaches of the legal requirements for environmental protection that apply in the area. The aim of this study was to assess the impacts of human activities in the Fildes Region by monitoring the distribution of bird and seal breeding sites and recording human activities and their associated environmental impacts. Data from an initial monitoring period 200306 were compared with data from 200810. We observed similar or increased levels of air, land and ship traffic, but fewer violations of overflight limits near Antarctic Specially Protected Area No. 150 Ardley Island. Open waste dumping and oil contamination are still major environmental impacts. Scientific and outdoor leisure activities undertaken by station personnel are more frequent than tourist activities and are likely to have a commensurate level of environmental impact. Despite the initial success of some existing management measures, it is essential that scientific and environmental values continue to be safeguarded, otherwise environmental impacts will increase and the habitat will be further degraded. We argue that the Fildes Region should be considered for designation as an Antarctic Specially Managed Area, a measure that has proven effective for environmental management of vulnerable areas of the Antarctic.Keywords: human impact; Antarctic; Fildes Region; environmental management; Antarctic Specially Managed Area; protected area(Published: 18 May 2012)Citation: Polar Research 2012, 31, 18206, http://dx.doi.org/10.3402/polar.v31i0.1820