Habitat structure modulates nestling diet composition and fitness of Blue Tits Cyanistes caeruleus in the Mediterranean region

Capsule: The nestling diet of Blue Tits Cyanistes caeruleus is influenced by parental effort and habitat type, and consequently has an impact on breeding success.

Aims: In a three-year study, we compared the nestling diet of Blue Tits in two Mediterranean forests (pinewood and oakwood) and tested its implications for breeding success.

Methods: Adults were captured at the nest to obtain morphological measurements, and provisioning behaviour was recorded when chicks were 11 days old. Nestling tarsus length and body mass were measured on day 13 after hatching.

Results: Caterpillars constituted the largest proportion of nestling diet in both habitats, however, higher numbers and biomass of noctuid, as well as higher numbers of tortricid larvae, were provided to nestlings in the pinewood. Furthermore, females provided tortricids more often than males, whereas males supplied more geometrid larvae and spiders. We found a more generalist diet for nestlings raised in the pinewood. Also, a greater number of young fledged when their diet included more tortricids and was more generalist, and Blue Tit nestlings raised on a diet with a higher number of spiders were in better body condition.

Conclusion: Differences in nestling diet between habitat types contribute to explain variance in breeding performance and therefore demonstrate diverse foraging behaviour strategies among populations.     

Can changes in fishery landings explain long-term population trends in gulls?

Capsule: Long-term population trends of gulls on the Isle of Canna, Scotland, showed a correlation to fish tonnage landed in a nearby port.

Aims: To assess whether gull numbers and breeding success at Canna have been influenced by the amount of fish discarded in the area.

Methods: We examined data on gull breeding numbers, breeding success and diet studied at Canna from 1969 to 2014, and data on fish landings at the nearby port of Mallaig for 1985 to 2014. We examined correlations between gull and fishery data, and performed a detrended analysis of Herring Gull Larus argentatus numbers in relation to demersal fish catch (the latter as a proxy for discard volumes).

Results: Gulls fed extensively on discards. Gull breeding numbers declined at Canna, especially between 2000 and 2006, the decline being more pronounced than seen in national totals. Gull breeding numbers correlated with demersal landings, even after detrending for long-term decreases in both.

Conclusions: Correlation between detrended Herring Gull breeding numbers and detrended demersal fish landings provided strong evidence for a causal link between fishery discarding and gull breeding numbers.     

Future breeding and foraging sites of a southern edge population of the locally endangered Black Guillemot Cepphus grylle

Capsule: One of the southernmost populations of the Black Guillemot Cepphus grylle is currently endangered, and the risk may be exacerbated by climate change.

Aims: We evaluated the future vulnerability of the Black Guillemot by predicting the impact of climate change on the geographic distribution of its breeding and foraging range in the Baltic Sea.

Methods: We used MaxEnt, a species distribution modelling technique, to predict the current and future breeding grounds and foraging sites.

Results: We found that although the foraging range is expected to increase in the southern Baltic Sea in future, these areas will no longer be suitable as breeding grounds due to a changing climate, creating a spatial mismatch.

Conclusion: Our predictions indicate where threats to the species may be most severe and can be used to guide conservation planning. We advocate conservation measures which integrate potential future threats and focus on breeding sites across the current and future potential geographic range of the Black Guillemot.     

Assessing the impact of extreme flooding on survival in a southern European population of White-throated Dippers Cinclus cinclus

Capsule: There were only weak effects of winter flooding episodes on apparent annual survival of a White-throated Dipper breeding population in northern Iberia.

Aims: To test whether extreme winter flooding episodes affected survival in a breeding population of White-throated Dippers Cinclus cinclus.

Methods: Dippers were ringed during the breeding seasons of seven consecutive years on rivers in northern Iberia. Cormack–Jolly–Seber models were used to estimate apparent annual survival in relation to flooding during the winter periods.

Results: We obtained weak evidence for an effect of flooding during the winter on the surveyed population. Two of the six winters were characterized by having an exceptionally high discharge. Our models showed that survival in the subsequent breeding period tended to be lower, although models assuming constant survival were equally well supported.

Conclusion: Extreme flooding in winter may affect survival of some White-throated Dippers in northern Iberia, but its impact at the population level seems to be weak.     

Co-occurrence and commensal feeding between Little Egrets Egretta garzetta and Eurasian Spoonbills Platalea leucorodia

Capsule: The spatial distribution and feeding efficiency of Little Egrets Egretta garzetta wintering in the gulf of Gabès, Tunisia, are affected by a commensal association with the Eurasian Spoonbills Platalea leucorodia.

Aims: To investigate the role of the interspecific interaction between Little Egrets and Eurasian Spoonbills in shaping the spatial distribution and feeding efficiency of Little Egrets.

Methods: Using count and behavioural data, we examined the co-occurrence of these species in flocks, and compared the foraging efficiency of Little Egrets feeding with Eurasian Spoonbills with that of solitary Little Egrets.

Results: We found that the presence of Eurasian Spoonbills doubled the chance of Little Egrets being present. Within mixed flocks, the number of Little Egrets increased with the number of Spoonbills. Moreover, Little Egrets foraging in association with Eurasian Spoonbills took fewer steps, had higher pecking rates and higher prey intake rates than solitary Little Egrets.

Conclusion: Little Egrets appear to obtain foraging efficiency benefits by following Eurasian Spoonbills. This interaction seems to play a role in determining the spatial distribution of Little Egrets.     

Environmental correlates of breeding abundance and population change of Eurasian Curlew Numenius arquata in Britain

Capsule: Across Britain, breeding Eurasian Curlew Numenius arquata are less numerous and have shown greater population declines in areas with more arable farming, woodland cover and higher generalist predator abundance.

Aims: We present the first national-scale analysis of the potential drivers of Curlew population change in Britain, which is needed to guide conservation action for this globally near-threatened, declining species.

Methods: Breeding Bird Survey data and environmental predictors were used to model variation in Curlew abundance in 1995–99 and 2007–11, and population change between these periods.

Results: Arable farming and woodland cover were negatively associated with Curlew abundance and population declines. Curlew abundance was positively associated with extent of protected area coverage and gamebird numbers. Abundance and population change were positively associated with cooler temperatures and higher summer rainfall, but negatively associated with numbers of generalist predators.

Conclusions: We found support for the negative effects of intensive agriculture, forestry, increases in generalist predator populations and climate warming on Curlew abundance and population change. Effective site protection and measures to reduce generalist predator abundance may be important conservation measures, together with improving breeding habitat quality in the wider countryside.     

Seasonal and spatial variation of the Montagu’s Harrier’s Circus pygargus diet in Eastern Poland

Capsule: The diet of the Montagu’s Harrier Circus pygargus is variable and comprises the most available prey at a given time of the season. We found no evidence for a relationship between diet and land-use in the core foraging zone.

Aims: We investigated whether the diet of the Montagu’s Harrier reflects the available prey and how it changes across the breeding season and in relation to land-use.

Methods: We analysed pellets collected at nests between 2007 and 2011. We looked for nonlinear patterns in the occurrence of prey categories in the pellets as a nonlinear function of the Julian date. Moreover, we tested whether the diet is affected by land-use within a radius of 2299 m from the nest.

Results: Four thousand four hundred and sixty-five prey items were found in 880 pellets and 76 prey remains collected at 63 sites. The diet did not depend on the land-use structure but showed a significant temporal variation.

Conclusions: The diet of the Montagu’s Harrier follows the availability of the prey in the foraging habitat. We conclude that the type of land-use in the vicinity of the nesting habitat has a rather weak effect on the diet of the Montagu’s Harrier.     

Trophic strategies of Yellow-legged Gull Larus michahellis on oceanic islands surrounded by deep waters

Capsule: The diet of Yellow-legged Gulls Larus michahellis on an oceanic island, surrounded by deep waters without a wide shelf, was mainly composed of terrestrial invertebrates.

Aims: To study the trophic ecology of Yellow-legged Gulls on an island surrounded by deep waters, to quantify the importance of terrestrial prey items and their availability, and to evaluate the relative importance of nutritional values of terrestrial and marine resources.

Methods: Diet was monitored for one year. We assessed the relative contribution of the main prey items and their macronutrients through the study of pellets and faeces.

Results: Terrestrial invertebrates were the most frequently consumed prey items (frequency of occurrence (FO) 67%), followed by marine fish (Osteichthyes FO 33%). Coleoptera and Orthoptera were the most consumed terrestrial invertebrates and provided a high nutritional value. The rate of consumption of terrestrial invertebrates varied in synchrony with the breeding season, being higher in spring, indicating their potential importance for reproduction.

Conclusion: It is unusual that terrestrial invertebrates constitute a large proportion of the diet of large gulls, but they seemed to cover their trophic energy requirements during the reproductive period.     

Density-dependent regulation of breeding success in the Red-crested Pochard Netta rufina

Capsule: Numbers of breeding Red-crested Pochard Netta rufina in the Czech Republic were positively correlated with reproductive success in the previous year, yet annual productivity, declined with increasing numbers of females at the beginning of the breeding season, suggesting local limiting factors on this population.

Aims: To test the hypothesis that long-term increases in numbers of a breeding population of Red-crested Pochard Netta rufina can be explained by the productivity (numbers of ducklings fledged) in the previous year. We also test for the potential adverse effect of population size on population productivity in the current year.

Methods: Data from 2004 to 2016 from South Bohemia, Czech Republic, were analysed using TRends and Indices for Monitoring Data software to investigate changes in numbers of adults, numbers of females at the start of the breeding season and number of broods produced.

Results: There was a significant increase in the numbers of adults and females at the beginning of each breeding season. Numbers of adults in May positively correlated with productivity (numbers of ducklings fledged) in the previous breeding season, but relative productivity (broods per adult female) in the current year was negatively correlated with females abundance at the beginning of the breeding season.

Conclusions: The study identifies density-dependent regulation as a factor in the population productivity of Red-crested Pochards using intensively managed fishponds as a breeding ground.     

Differences in time and space use between two sympatric Acrocephalus warblers with similar diets

Capsule: We found high diet overlap and different uses of space and time between Moustached Warblers Acrocephalus melanopogon and Reed Warblers Acrocephalus scirpaceus breeding in sympatry at a marshland in Spain.

Aims: To study the degree of diet overlap between both species, their space use on a local scale and their breeding phenologies.

Methods: We studied the breeding phenologies of the two species by standardized ringing activity. Spatial distribution was investigated by point counts. We determined diet composition from emetic samples and we collected invertebrates by standardized sweep-netting to estimate food availability.

Results: Diet and prey selection were similar among species. Conversely, spatial overlap was relatively small (<50%) and breeding phenologies were not synchronized. Both food availability and the overall abundance of the two species increased throughout the breeding season.

Conclusion: The two species are potential competitors for food and the observed differences in spatial and temporal niches may represent a way to lower competition for trophic resources: Moustached Warblers could reduce competition by breeding early, while Reed Warblers could avoid settling in areas occupied by the other species.     

Changes in upland bird abundances show associations with moorland management

Capsule: Changes in abundance of six bird species showed associations with moorland management.

Aims: To assess responses of breeding birds to moorland management over a 14-year period.

Methods: Vegetation and birds were surveyed at 2–3-year intervals and changes examined in relation to sheep and cattle grazing, vegetation burning and cutting.

Results: Seven correlations between change in management and change in bird abundance were detected, and six between change in vegetation and change in bird abundance. On plots where sheep numbers declined, Golden Plover Pluvialis apricaria and Northern Wheatear Oenanthe oenanthe declined. Where a greater area was burned, Golden Plover increased in the initial post-burning period but Red Grouse Lagopus lagopus scotica declined. Eurasian Curlew Numenius arquata and Sky Lark Alauda arvensis increased where a greater area of moorland vegetation was cut. Whinchat Saxicola rubetra declined with increasing cattle numbers on a plot.

Conclusions: Bird populations respond to changes in moorland management, but these changes are not always associated with detectable changes in vegetation. These responses of moorland breeding birds to management could help refine agri-environment options and other conservation interventions on moorland. Responses differed between bird species, ideally requiring site-specific planning where managing for multiple species is a goal.     

Vegetation structure influences foraging decisions in a declining grassland bird: the importance of fine-scale habitat and grazing regime

Capsule: Whinchat Saxicola rubetra foraging behaviour was significantly influenced by habitat structure and grazing.

Aims: To assess how foraging habitats selected by breeding Whinchats differed from wider territory attributes under contrasting grazing management in multiple upland areas in Scotland: principally sheep grazed, Red Deer grazed or ungrazed, and to identify how differing land use may limit suitable foraging areas.

Methods: We compared fine-scale vegetation structure in patches chosen for foraging by Whinchats in contrasting grazing management regimes.

Results: Whinchats were less likely to forage in patches with a greater cover of bracken and tall non-bracken vegetation, regardless of grazing regime. Grass cover influenced foraging behaviour in ungrazed habitats only, where Whinchats were less likely to forage in areas with high grass cover.

Conclusion: Whinchats appear to require a mosaic or range of sward structures within breeding territories, highlighting the importance of establishing how vegetation structure influences breeding birds at different spatial scales. Our results suggest that suitable foraging patches were plentiful within grazed habitats but potentially limited in ungrazed habitats. Further work is needed to identify management regimes and interventions to maintain conditions suitable for breeding Whinchats that are compatible with other land use and conservation objectives.     

Habitat structure influences the song characteristics within a population of Great Tits Parus major

Capsule: The structure of Great Tit Parus major songs is shaped by the acoustic properties of the habitat within the breeding territory of individuals.

Aim: To test whether the structure of the habitat influences song structure within a population of Great Tits P. major.

Methods: We recorded Great Tit songs from 42 territories on two different days and measured the habitat structure in each territory. We also trapped the males and estimated the breeding density around each territory, so were able to control the analysis by date, breeding density and male characteristics.

Results: Song pause length was positively affected by the ground cover, while the song rate and the minimum frequency were negatively affected by the shrub cover. Male size negatively affected the peak frequency of the songs, whereas the age of the males affected the frequency range; older males sang with a broader bandwidth.

Conclusion: This study suggests that Great Tits are capable of adjusting their vocalizations in each territory, presumably to enhance transmission owing to vocal plasticity.     

Age-related effects on breeding phenology and success of Common Guillemots Uria aalge at a North Sea colony

Capsule: Common Guillemots Uria aalge show delayed breeding and marked age-related changes in reproductive success consistent with improved performance with experience.

Aims: To determine age of first breeding and age-related effects on breeding phenology and success of Common Guillemots.

Methods: Resighting data from a long-term colour-ringing study of Common Guillemot chicks were combined with observations of breeding phenology and success to follow the recruitment process, breeding phenology and success of 62 birds at a major North Sea colony over a 30-year period.

Results: The median age of first breeding of Common Guillemots was 6.6 years. There were no detectable costs of first breeding on return rates or the likelihood of breeding the next season but first time breeders bred later and less successfully. Age of first breeding and lifetime breeding success both varied among individuals but there was no clear optimal age of first breeding and early first breeding was not associated with higher lifetime breeding success.

Conclusions: Common Guillemots in the Isle of May population delayed breeding for 3–4 years beyond physiological maturity. The marked increase in breeding success with age was consistent with improved performance with experience rather than selection for higher quality individuals. Findings from this study will inform population models by providing improved estimates of age of first breeding and age-related changes in reproductive performance.     

Limited prospecting behaviour of juvenile Eagle Owls Bubo bubo during natal dispersal: implications for conservation

Capsule Features of the breeding population and temporary settlement area influence the behaviour of Eagle Owls Bubo bubo prospecting for breeding sites during natal dispersal.

Aims To understand how prospecting behaviour during natal dispersal is affected by (i) the main characteristics of the breeding and dispersing portions of the population and (ii) main prey availability.

Methods We explored the ten-year dynamics and characteristics of radio-tagged breeders and dispersers of an Eagle Owl population.

Results During the first years following natal dispersal there was little prospecting behaviour of nesting sites and birds remained mainly within non-breeding settlement areas, bordering the sector occupied by the breeding population. Settlement areas had an abundant food supply, and low intraspecific competition and mortality. We suggest that these features of the settlement areas may reduce the willingness of individuals to search for breeding sites and may have the potential to impact on the viability of breeding populations.

Conclusion From a conservation perspective, the lengthy use of the temporary settlement areas by juvenile Eagle Owls suggests that the sites should be considered as important as the breeding areas when planning conservation strategies. Reducing juvenile mortality in settlement areas may represent an overlooked conservation strategy for long-lived species and may have a crucial effect on the viability some animal populations.     

Association of IL-10 (-819T/C, -592A/C and -1082A/G) and IL-6 -174G/C gene polymorphism and the risk of pneumonia-induced sepsis

Context: Association between inherited variants and the risks of sepsis is controversial.

Objective: To evaluate the risk of pneumonia-induced sepsis by examining its linkage with polymorphisms of IL-6 and IL-10.

Materials and methods: Samples were obtained from 188 pneumonia-induced sepsis patients, 162 pneumonia patients and 200 healthy controls.

Results: Subjects with IL-10 -1082 AA genotypes and IL-6 -174?CC genotype had a higher risk of sepsis and increased mRNA levels.

Conclusion: The variants of IL-10 -1082 A allele and IL-6 -174 C allele contributed to an increased risk of pneumonia-induced sepsis.     

Evidence for deleterious effects of harness-mounted satellite transmitters on Saker Falcons Falco cherrug

Capsule This study identifies lethal and sub-lethal effects associated with the deployment of harness-mounted satellite transmitters on a large falcon species.

Aims We examined the effect of harness-mounted satellite transmitters and patagial tags on survival, behaviour and physical health of adult Saker Falcons.

Methods We compared breeding turnover of Saker Falcons deployed with harness-mounted satellite transmitters or patagial tags with unmarked birds identified by using genetic markers. In addition, observational data were recorded on the breeding behaviour and physical condition of birds with satellite transmitters.

Results This study found evidence of decreased survival, together with sub-lethal behavioural and physical effects, associated with the deployment of harness-mounted satellite transmitters on Saker Falcons. We found no effect of fitting patagial tags on breeding turnover, although the removal of patagial tags by several birds may have indicated they caused some degree of discomfort.

Conclusion Researchers using harness-mounted transmitters on this, and similar, falcon species need to assess how these deleterious effects may impact on species conservation, the welfare of individual birds and the interpretation of their studies.     

Circulating levels of apoptotic markers and oxidative stress parameters in women with polycystic ovary syndrome: a case-controlled descriptive study

Context: Apoptotic dysregulation plays a role in the pathogenesis of polycystic ovary syndrome (PCOS).

Objective: To evaluate circulatory apoptotic markers and oxidative stress in patients with PCOS.

Materials and methods: Forty-four women with PCOS, and 44 healthy women as controls were enrolled in the study. Oxidative stress parameters and caspases levels were measured in serum.

Results: The caspase 9 level was significantly lower and related with oxidant status in patients with PCOS, while the circulating levels of caspases 3 and 7 were statistically similar in both groups.

Discussion: This study is the first report demonstrating the circulating levels of apoptotic markers and their relationship with oxidant status in PCOS.

Conclusion: The circulating caspase 9 and oxidant status might contribute to apoptotic dysregulation in PCOS.     

Summer in the city: behaviour of large gulls visiting an urban area during the breeding season

Capsule: Large numbers of Herring Gulls Larus argentatus and Lesser Black-backed Gulls Larus fuscus from a traditional colony in the Netherlands visit an urban area for food in the chick rearing period, causing nuisance while doing so.

Aims: To assess the potential contribution of large gulls breeding in a traditional colony to gull–human conflicts in cities.

Methods: Colour-ringed gulls from a nearby colony were counted in the study area throughout the 2014 breeding season. The average numbers observed daily per species and sex were compared between different breeding phases.

Results: Fluctuations in numbers of both species could be explained by breeding phase. Numbers of females of both species and male Lesser Black-backed Gulls dropped significantly during laying and incubation. Numbers peaked post-hatching, coinciding with increased engagement in nuisance events and more frequent displacements within the study area.

Conclusion: Large gulls from a traditional colony frequently visited the urban study area, especially when food demand for chick provisioning was high, suggesting that city visits are motivated by accessibility of urban food. The proportion of rooftop breeding gulls in this area is low. Therefore, measures to avoid nuisance should focus on reducing food availability rather than controlling gull breeding.     

Validation of a protein panel for the noninvasive detection of recurrent non-muscle invasive bladder cancer

Context: About 50–70% of patients with non-muscle invasive bladder cancer (NMIBC) experience relapse of disease.

Objective: To establish a panel of protein biomarkers incorporated in a multiplexed microarray (BCa chip) and a classifier for diagnosing recurrent NMIBC.

Materials and methods: Urine samples from 45 patients were tested. Diagnostic performance was evaluated by receiver operating characteristic (ROC) analysis.

Results: A multi biomarker panel (ECadh, IL8, MMP9, EN2, VEGF, past recurrences, BCG therapies and stage at diagnosis) was identified yielding an area under the curve of 0.96.

Discussion and conclusion: This biomarker panel represents a potential diagnostic tool for noninvasive diagnosis of recurrent NMIBC.