Kate Risely

Comparison of trends in butterfly populations between monitoring schemes

Butterflies are an important indicator of the impacts of environmental change. Butterfly monitoring schemes (BMS) have provided national and Europe-wide trends in their abundance and been widely used for research. Most schemes sample sites that are self-selected by contributors and therefore tend to cover locations that are rich in butterflies. To provide a more representative assessment of butterfly populations, the wider countryside butterfly survey (WCBS) was developed with a stratified-random sample of survey sites across the UK. We compare butterfly trends from the WCBS locations against those measured from traditional butterfly transects which are typically located in areas of good quality semi-natural habitats. Across the 26 species analysed, there was a significant positive relationship between trends measured from the two schemes between 2009 and 2013, the period when both schemes were operating fully. There was a tendency (17 out of 26 species analysed) for these changes to be greater within WCBS compared to traditional BMS transects, although this effect was not consistent across comparisons between pairs of consecutive years. When assessing these individual year-to-year changes, there was however a significant correlation between the two schemes in all cases. Over relatively short time periods, weather patterns are likely to dominate butterfly population fluctuations and lead to comparable trends across monitoring schemes. Over longer time periods, differences in land management may affect habitat condition differently for protected areas versus the wider countryside and it is therefore important to maintain comprehensive butterfly monitoring programmes to detect and interpret such effects.

Species traits explain variation in detectability of UK birds

Capsule Heterogeneous detectability amongst species may impact multi-species bird surveys and if not accounted for, may bias community level conclusions. Estimates of detectability were produced for 195 UK bird species, and detectability was significantly affected by bird size, diet and habitat specialization. Aims To estimate detectability and understand which species traits may impact detectability. Methods We estimated the detectability of 195 species of birds in the UK using distance sampling methods and examined the average detectability of genetically related groups. We tested the significance of species traits in describing variation in detectability, whilst controlling for phylogenetic relationships. Results Passeriformes had the lowest median detectability of 0.37 and Charadriiformes the highest median detectability of 0.65, of the seven largest orders considered. Species most associated with closed habitats such as woodland and urban areas had the lowest detectability. Smaller species had lower detectability than larger species. Conclusion Heterogeneity in species detectability could lead to biased conclusions, particularly when calculating multi-species indices such as species richness or diversity. Accounting for detectability will be most important in studies that cover a wide range of habitat types or a diverse spread of taxa.

Bird ringing in Britain and Ireland in 2004

This is the 68th annual report of the British Trust for Ornithologys Ringing Scheme, covering work carried out, and data received, in 2004. During the year, changes in bird survival in relation to winter weather were studied. In almost all cases, there was a greater influence of weather on first‐year than adult survival. A paper providing guidelines to help those setting up demographic monitoring schemes for waders was produced, with ringing as a key component. Concern about a reduction in reporting rates of ringed birds led to a study of the changes. Declines were found across nearly all taxonomic groups and may reflect a combination of changes in reporting behaviour, ringing behaviour or bird behaviour. A study of the timing of muirburning used the ringing dates of pulli in conjunction with nest record data to assess its possible effect on breeding birds. There appears to be little reason for differences in cut‐off dates for muirburning in different regions and at different altitudes, but further work is required to quantify more fully the effects on moorland birds. Data gathered as part of the Constant Effort Sites (CES) Scheme showed increases in the numbers of adults of several, mainly migrant, species, possibly as a result of high rainfall in Africa south of the Sahara. Productivity was good for most species. Cettis Warbler Cettia cetti was added to the list of species covered and a study of habitat on CE sites showed that vegetation management mitigates the effect of habitat progression on catching rates. Data for 117 Retrapping Adults for Survival (RAS) studies were submitted. Over 12,000 Swallows Hirundo rustica were ringed as part of the Swallow Roost Project. The total number of birds ringed (881, 920) was the highest ever, showing an 18% increase on the mean of the previous five years (1999–2003). The recovery total (11,930) also increased (by 9% compared to the mean of the previous five years). Recoveries of 154 BTO‐ringed birds and 102 ringed abroad are presented in the report. They include records that confirm suspected or known migration patterns as well as the more unexpected movements

Bird ringing in Britain and Ireland in 2005

This is the 69th annual report of the British Trust for Ornithologys Ringing Scheme, covering work carried out, and data received, in 2005. Important research on Oystercatchers Haematopus ostralegus in North Wales showed that survival of adults, recruitment of juveniles and mass of both adults and juveniles were lower during winters when there was mechanised dredging for shellfish. A study of weight changes of House Sparrows Passer domesticus in autumn and winter found that they spread their weight gain through the day, thus potentially decreasing their risk of predation, but increasing their risk of starvation. Data gathered as part of the Constant Effort Sites (CES) Scheme showed an annual increase in adult numbers for five species (one migrant and four residents) and an annual decrease for five species (four migrants and one resident). Productivity was variable with 11 species having above‐average productivity and 13 below‐average. Work began to develop methods to produce annual survival trends by integrating CES data from the 350 sites that have taken part in CES over the last 21 years. Data for 110 Retrapping Adults for Survival (RAS) studies were submitted. Over 13,000 Swallows were ringed as part of the Swallow Roost Project, which ran until 2006. The total number of birds ringed (873,581) was exceeded only in 2004 and was a 12% increase on the mean of the previous five years (2000–04). The recovery total (12,658) was the second highest in the last decade, being exceeded only in 2004, and was 9% higher than the mean of the previous five years. A total of 236 selected recoveries are presented in the report. They include unexpected movements and others that confirm suspected or known migration patterns.

Patterns and causes of covariation in bird and butterfly community structure

ContextVariation in biological communities is used to identify biodiversity responses to anthropogenic drivers, and to guide conservation responses. Often, such data are only available for a limited group of species, with uncertain applicability to unmonitored taxa.ObjectiveUsing equivalent data on the community structure of two contrasting taxa, we examine spatial co-variation in both communities, and test the extent to which any associations may result from large-scale latitudinal patterns, variation in habitat-type, or other factors.MethodsBirds and butterflies were surveyed using standard methods across a stratified random sample of 1-km2 squares across the UK. Four measures of community structure were calculated and used to examine their association between the two taxa, before accounting for effects of latitude, habitat-type and observer.ResultsSpecies richness, diversity and community specialisation were significantly correlated between birds and butterflies, but evenness was not. There were strong latitudinal gradients in bird community specialisation, and butterfly richness and diversity. Habitat diversity significantly affected bird communities, whilst butterfly evenness and specialisation was reduced on farmland and human-related habitats. Covariation in richness and diversity between taxa remained after including effects of latitude and habitat-type.ConclusionsSurrogacy approaches may be useful when considering fine-scale variation in species richness and diversity to inform site-based conservation and management decisions. However, limited covariance in evenness and specialisation metrics suggest that decisions based on the needs of rare or specialist species may be less relevant to other taxa.

Bird ringing in Britain and Ireland in 2006

This is the 70th annual report of the British Trust for Ornithologys Ringing Scheme, covering work carried out, and data received, in 2006. During the year recoveries of ringed birds were used to assess the possibility of highly pathogenic Avian Influenza H5N1being spread across Europe and into Britain by wild birds. Recovery reports were vital in understanding this risk and advising government. A study of wader survival using existing data showed that monitoring is possible, but is less effective in sites where there are low encounter rates. Constant Effort Site (CES) data show how widely adult numbers can vary from year to year, with six species showing a significant reversal in trend (with five having fallen) from the previous year. There is particular concern for Bullfinch as adult numbers decreased by 16% in 2006, a continuing downward trend that has seen numbers of the species halve since the 1970s. Five species showed a significant increase in productivity when compared to the previous year, while four showed a significant decrease. Data for 106 Retrapping Adults for Survival (RAS) studies were submitted. The final year of fieldwork for the Swallow Roost Project was completed. Although the total number of birds ringed (853,681) was lower than that in both 2005 and 2004, it was a 1% increase on the mean of the years 2002–05. The recovery total (13,785) was the highest since 1991, and was 16% higher than the mean of the previous five years. Recoveries of 251 individual birds are presented in the report. They include unexpected movements, movements that confirm suspected or known migration patterns, and longevity records.

Health hazards to wild birds and risk factors associated with anthropogenic food provisioning

Provision of supplementary food for wild birds at garden feeding stations is a common, large-scale and year-round practice in multiple countries including Great Britain (GB). While these additional dietary resources can benefit wildlife, there is a concomitant risk of disease transmission, particularly when birds repeatedly congregate in the same place at high densities and through interactions of species that would not normally associate in close proximity. Citizen science schemes recording garden birds are popular and can integrate disease surveillance with population monitoring, offering a unique opportunity to explore inter-relationships between supplementary feeding, disease epidemiology and population dynamics. Here, we present findings from a national surveillance programme in GB and note the dynamism of endemic and emerging diseases over a 25-year period, focusing on protozoal (finch trichomonosis), viral (Paridae pox) and bacterial (passerine salmonellosis) diseases with contrasting modes of transmission. We also examine the occurrence of mycotoxin contamination of food residues in bird feeders, which present both a direct and indirect (though immunosuppression) risk to wild bird health. Our results inform evidence-based mitigation strategies to minimize anthropogenically mediated health hazards, while maintaining the benefits of providing supplementary food for wild birds. This article is part of the theme issue ‘Anthropogenic resource subsidies and host–parasite dynamics in wildlife’.

Spatio-temporal dynamics and aetiology of proliferative leg skin lesions in wild British finches

Proliferative leg skin lesions have been described in wild finches in Europe although there have been no large-scale studies of their aetiology or epizootiology to date. Firstly, disease surveillance, utilising public reporting of observations of live wild finches was conducted in Great Britain (GB) and showed proliferative leg skin lesions in chaffinches (Fringilla coelebs) to be widespread. Seasonal variation was observed, with a peak during the winter months. Secondly, pathological investigations were performed on a sample of 39 chaffinches, four bullfinches (Pyrrhula pyrrhula), one greenfinch (Chloris chloris) and one goldfinch (Carduelis carduelis) with proliferative leg skin lesions and detected Cnemidocoptes sp. mites in 91% (41/45) of affected finches and from all species examined. Fringilla coelebs papillomavirus (FcPV1) PCR was positive in 74% (23/31) of birds tested: a 394 base pair sequence was derived from 20 of these birds, from all examined species, with 100% identity to reference genomes. Both mites and FcPV1 DNA were detected in 71% (20/28) of birds tested for both pathogens. Histopathological examination of lesions did not discriminate the relative importance of mite or FcPV1 infection as their cause. Development of techniques to localise FcPV1 within lesions is required to elucidate the pathological significance of FcPV1 DNA detection.