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Wildlife conservation policies directed at common and widespread, but declining, species are difficult to design and implement effectively, as multiple environmental changes are likely to contribute to population declines. Conservation actions ultimately aim to influence demographic rates, but targeting actions towards feasible improvements in these is challenging in widespread species with ranges that encompass a wide range of environmental conditions. Across Europe, sharp declines in the abundance of migratory landbirds have driven international calls for action, but actions that could feasibly contribute to population recovery have yet to be identified. Targeted actions to improve conditions on poor-quality sites could be an effective approach, but only if local conditions consistently influence local demography and hence population trends. Using long-term measures of abundance and demography of breeding birds at survey sites across Europe, we show that co-occurring species with differing migration behaviours have similar directions of local population trends and magnitudes of productivity, but not survival rates. Targeted actions to boost local productivity within Europe, alongside large-scale (non-targeted) environmental protection across non-breeding ranges, could therefore help address the urgent need to halt migrant landbird declines. Such demographic routes to recovery are likely to be increasingly needed to address global wildlife declines. [ABSTRACT FROM AUTHOR]

This is the 79thannual report of the British Trust for Ornithology’s Ringing Scheme, incorporating the report of the Nest Record Scheme and covering work carried out and data processed in 2015. Constant Effort Sites (CES) data from across Europe, relating to eight common warblers, were analysed to investigate large-scale variation in survival rates and showed that changes in survival outside the breeding season are not a key driver of long-term population trends. Retrapping Adults for Survival (RAS) seabird data sets were reviewed to understand their ability to supplement geographically limited, long-term studies carried out by professionals. Most RAS studies re-encountered sufficient numbers of seabirds to estimate average survival rates; however, only those with re-encounter rates of around 40% were able to detect changes in survival rates efficiently. Over 100,000 nest records, relating to four insectivorous woodland passerines, were used to investigate changes in laying dates in response to temperature. Laying dates advanced by 2.3–4.8 days per °C rise in temperature, suggesting that these species may be able to change their laying dates in response to climate changes, even if the rate of climate change is rapid. Over 10,000 phenological data sets, including laying dates for 37 bird species, were used to look at the mechanisms behind species’ responses to changes in climate. Primary producers and primary consumers advanced timing of breeding more quickly than secondary consumers, potentially leading to a greater mismatch between the timing of breeding in birds (secondary consumers) and their prey availability under future climate-change projections. Data were received for 134 CE sites in 2015. Long-term (1984–2014) population trends derived from the CES data identified five migrant species and four resident species that have decreased significantly in abundance over this period. Abundance of three species decreased significantly in 2015 compared to the five-year mean (2010–14) with WhitethroatSylvia communisabundance at its lowest since CES monitoring began. There were significant increases in abundance for 12 species, with GoldfinchCarduelis carduelisat its highest since CES monitoring began. Productivity decreased significantly in ten species and increased significantly in three species compared to the five-year mean (2010–14); productivity for Willow WarblerPhylloscopus trochiluswas at its lowest since CES began. There were no significant changes in survival in 2015. The total number of active RAS projects increased again in 2015; 190 submissions were received, including data from 23 new projects. Projects were carried out on 57 species, with Pied FlycatcherFicedula hypoleuca(23 projects), Sand MartinRiparia riparia(15) and House SparrowPasser domesticus(20) still the most-studied species. The total number of birds ringed in 2015 was just under one million (987,253) and comprised 472,462 first-year birds, 319,230 adults (birds in their second calendar year or older), 27,993 unaged birds and 167,568 nestlings. In addition, there were 236,540 recaptures of ringed birds at or near the ringing site. In total, 32,253 recoveries (birds found dead, or recaptured or resighted at least 5 km from the place of ringing) of BTO-ringed birds were reported in 2015. A selection of recoveries that have extended our knowledge of movements is presented, as well as longevity records established during the year. In total, 48,957 nest records were received for 2015, the highest annual submission since the Scheme began in 1939. Mean laying dates for five species were significantly earlier than the five-year mean (2010–14) with nine species laying significantly later. Only one species showed a significant increase in breeding success (fledglings per breeding attempt) in 2015, with four decreasing significantly. A total of 612 permits/licences to disturb breeding birds on Schedule 1 of the Wildlife and Countryside Act 1981 (as amended), were prepared/issued in 2015, a small increase from 2014. During 2015, the use of special methods was authorised for 489 marking projects and 68 trapping projects, 25% more than in 2014. [ABSTRACT FROM PUBLISHER]

Male-biased sex ratios occur in many bird species, particularly in those with small or declining populations, but the causes of these skews and their consequences for local population demography are rarely known. Within-species variation in sex ratios can help to identify the demographic and behavioural processes associated with such biases., Small populations may be more likely to have skewed sex ratios if sex differences in survival, recruitment or dispersal vary with local abundance. Analyses of species with highly variable local abundances can help to identify these mechanisms and the implications for spatial variation in demography. Many migratory bird species are currently undergoing rapid and severe declines in abundance in parts of their breeding ranges and thus have sufficient spatial variation in abundance to explore the extent of sex ratio biases, their causes and implications., Using national-scale bird ringing data for one such species (willow warbler, Phylloscopus trochilus), we show that sex ratios vary greatly across Britain and that male-biased sites are more frequent in areas of low abundance, which are now widespread across much of south and east England. These sex ratio biases are sufficient to impact local productivity, as the relative number of juveniles caught at survey sites declines significantly with increasing sex ratio skew., Sex differences in survival could influence this sex ratio variation, but we find little evidence for sex differences in survival increasing with sex ratio skew. In addition, sex ratios have become male-biased over the last two decades, but there are no such trends in adult survival rates for males or females. This suggests that lower female recruitment into low abundance sites is contributing to these skews., These findings suggest that male-biased sex ratios in small and declining populations can arise through local-scale sex differences in survival and dispersal, with females recruiting disproportionately into larger populations. Given the high level of spatial variation in population declines and abundance of many migratory bird species across Europe at present, male-biased small populations may be increasingly common. As singing males are the primary records used in surveys of these species, and as unpaired males often sing throughout the breeding season, local sex ratio biases could also be masking the true extent of these population declines. [ABSTRACT FROM AUTHOR]

This is the 78thannual report of the British Trust for Ornithology's Ringing Scheme, incorporating the report of the Nest Record Scheme and covering work carried out and data processed in 2014.Many species have shifted their range towards the Earth's poles in response to global temperature increases. Data from four European Constant Effort Sites (CES) ringing schemes were examined to determine the impact of large-scale temperature variations on productivity in a group of seven migratory bird species to determine the potential for future range changes. Increased productivity at northern sites was apparent only in Reed WarblerAcrocephalus scirpaceus, although there was evidence of local adaptation in six species, suggesting that the rate of northward range shift may be constrained by adaptation to local climatic conditions.A study on the role of carry-over effects in RedstartPhoenicurus phoenicurus, Spotted FlycatcherMuscicapa striataand Wood WarblerPhylloscopus sibilatrixfound that carry-over effects from passage regions impacted on the timing of breeding more strongly than climate on the breeding grounds and that warmer conditions in the breeding area were not associated with reduced productivity.Work on the impact of environmental variables on annual population changes found that, over 40 years, the strongest impact on migrants was rainfall in the Sahel. Over 25 years, positive population changes in response to wetter winters were found for 12 of 16 species studied.Data were submitted for 132 CE sites in 2014. Long-term (1984–2013) population trends derived from the CES data have changed little in the past year. The abundance of five migrant species and five resident species decreased significantly in 2014 compared to the five-year mean (2009–13). The abundance of five of these species (Willow WarblerPhylloscopus trochilus, Sedge WarblerAcrocephalus schoenobaenus, BlackbirdTurdus merula, ChaffinchFringilla coelebsand GreenfinchChloris chloris) was at its lowest since CES monitoring began. There were significant increases in abundance for three species. Productivity decreased significantly in Willow TitPoecile montanacompared to the five-year mean (2009–13), but there were significant increases for eleven species (seven residents and four migrants),with productivity for Reed Warbler, Blackbird and BullfinchPyrrhula pyrrhulaat its highest since CES began. There were only two significant changes in survival in 2014.A total of 176 Retrapping Adults for Survival (RAS) projects were active in 2014, the highest total ever, with 22 new projects starting, 17 of which involved RAS target species. Projects were carried out on Tawny OwlStrix alucoand SwiftApus apusfor the first time.The total number of birds ringed in 2014 exceeded one million for the third time (1,047,026) and comprised 520,477 first-year birds, 303,086 adults (birds in their second calendar year or older), 29,799 unaged birds and 193,664 nestlings. In addition, there were 226,303 recaptures of ringed birds at or near the ringing site.In total, 28,187 recoveries of BTO-ringed birds were reported for 2014. A selection of recoveries that have extended our knowledge of movements is presented, as well as longevity records established during the year. The numbers of birds recovered between 2010 and 2013 have been revised as data submitted as retraps have been examined and some have been reclassified as recoveries.For the fifth year running, annual totals of nest records surpassed 40,000, reaching 46,382. Mean laying dates for 55 species were significantly earlier than the five-year mean (2009–13) with 19 species laying significantly later than the five-year mean. Breeding success (fledglings per breeding attempt) increased significantly for 14 species, with none showing a decrease.Nearly 600 permits/licences to disturb breeding birds on Schedule 1 of the Wildlife and Countryside Act (1981), were prepared/issued in 2014, a small increase from 2013.The use of special methods was authorised for 398 marking projects and 47 trapping projects in 2014, 12% fewer than in 2013. [ABSTRACT FROM PUBLISHER]

Higher temperatures resulting from climate change have led to predictions that the duration of the breeding season of many temperate bird species may be changing. However, the extent to which breeding seasons can be altered will also depend on the degree of flexibility in processes occurring at other points in the annual cycle. In particular, plasticity in the timing of post-breeding moult ( PBM) could facilitate changes in the timing of key events throughout the annual cycle, but little is known about the level of within- and between-species plasticity in PBM. As part of the British Trust for Ornithology ( BTO) Ringing Scheme, many ringers routinely record moult scores of flight feathers, and these can be used to provide information on the annual progression of PBM for a range of species. Here we use ringing data to investigate patterns of PBM in 15 passerines, as well as data from the BTO Nest Record Scheme to relate these differences to the timing of breeding of these species across the UK. We find considerable variation in both the mean start (19 May-29 July) and duration (66-111 days) of PBM between species, but find no evidence that species starting PBM later in the season complete it any faster. However, there is considerable within-species variation in PBM, particularly for multi-brooded species; PBM starts later and is completed in less time when the duration of the breeding season (difference between first and last nests) is longer. This implies that a later end to breeding can be compensated for by faster PBM, and that advances in breeding could lead to earlier and slower PBM. Our findings suggest that adaptation of PBM in response to climate-mediated changes in the timing and duration of the breeding season is possible. However, the requirement to complete PBM prior to migration or the onset of winter might constrain the extent to which breeding seasons can lengthen, especially for later nesting species. [ABSTRACT FROM AUTHOR]

This is the 77th annual report of the British Trust for Ornithology's Ringing Scheme, incorporating the report of the Nest Record Scheme and covering work carried out and data processed in 2013. In recent years the schemes have focused on the collection of demographic data as part of our Integrated Population Monitoring programme. We expanded (from 10 to 17) the number of species for which we were able to construct integrated models and identified differences in the relative contributions of recruitment and adult survival to population change between increasing and decreasing species. Recruitment of young into the breeding population can be difficult to estimate. We investigated the use of proportions of birds in their second calendar year, or older, caught in the early summer using Blackbird Turdus merula as a model. Results showed that recruitment was a more important determinant of population change than survival. Changes in phenology are being documented widely and we carried out analyses looking at the timing of moult and reproduction in selected passerine species. Patterns in timing and duration of moult varied between resident species but were more aligned within migrant species, which also moulted faster. Temperature on spring breeding grounds accounts for more variation between years in breeding phenology than precipitation rates on the wintering grounds in 19 migrant species but neither climate variable affected clutch size. We continued to emphasise the value of targeted ringing and nest recording; increased participation in our structured ringing schemes has provided additional opportunities to improve the quality of demographic monitoring. Long-term (1984–2012) population trends derived from the Constant Effort Sites (CES) data have changed little in the past year. Three of the eight migrant species monitored by CES showed significant increases in productivity compared to the five-year average, although Sedge Warbler Acrocephalus schoenobaenus recorded its second-lowest productivity since CES began in 1983. Breeding performance of residents was mixed, with juvenile:adult ratios for some early breeders significantly lower than during the preceding five years, but significantly higher for some late breeders; one late-breeding resident species, Bullfinch Pyrrhula pyrrhula, had its highest productivity since CES began. Data were submitted for 124 sites. The number of active RAS projects in 2013 was 154, with 22 new projects, 13 of which involved RAS target species. The total number of birds ringed in 2013 decreased slightly (952,750) compared to 2012 and comprised 424,401 first-year birds, 355,278 adults (birds in their second calendar year or older), 19,776 unaged birds and 153,295 nestlings. In addition, there were 241,111 recaptures of ringed birds at or near the ringing site. The reduction in numbers ringed compared to 2012 was probably a result of weather events in 2013. In 2013, there were 465 colour-marking projects registered, covering a total of 110 species; 65 new projects were registered during the year. There were 21,275 recoveries of BTO-ringed birds: the highest total ever. A selection of recoveries that have extended our knowledge of movements is presented, as well as longevity records established during the year. In total, 40,384 nest records were submitted. Of these, 82% originated from England, 8% from Wales and 9% from Scotland, the remaining 1% divided between Northern Ireland and the Republic of Ireland. This was a reduction on the 2012 totals and probably reflected the poor start to the breeding season caused by the exceptionally cold weather in early spring. Long-term trends in nest productivity (fledglings per breeding attempt) were significant for 44 of the 72 species monitored. Of these, thirteen trends were negative, indicating a decline in breeding success over time. [ABSTRACT FROM AUTHOR]

Tracking devices are useful in studying the movement and behaviour of birds throughout the year. However, the effects of device attachment must be monitored for bird welfare and the scientific veracity of information gathered. We report on a trial of three different harness types (leg-loop, body and wing) for attaching GPS devices to Lesser Black-backed Gulls Larus fuscus and of a leg-loop harness on Great Skuas Stercorarius skua. This trial evaluated the functionality of the device whilst deployed, harness retention and the effects of each harness on the birds. The leg-loop harness prevented the devices from charging, due to feathers overlapping their solar panels, and individuals of both species shed this attachment during the first breeding season. For Lesser Black-backed Gull, devices functioned properly when attached using body and wing harnesses; foraging behaviour and territory attendance of birds were similar to the findings of other studies. Despite small sample sizes, annual adult survival rates for Lesser Black-backed Gull were similar to published estimates, suggesting harnesses had no deleterious effects. The wing harness has a smaller amount of skin contact than the body harness, and a non-constricting fit that better accommodates changes in body size. The wing harness was therefore considered the most appropriate for long-term studies. [ABSTRACT FROM AUTHOR]

This is the 76th annual report of the British Trust for Ornithology's Ringing Scheme, covering work carried out and data processed in 2012. Demographic integrated population monitoring has been the focus of the Scheme priorities in recent years and models that integrate ringing and nest record data and abundance trends were built for ten species for which sufficient data were available. Population drivers vary between species but they can be split between changes in breeding success, survival, or both. Multi-brooded species exhibited more seasonal variation in reproductive output than single-brooded species. In particular, migratory species showed a seasonal decrease in fledgling output, as do single-brooded species while residents generally showed a seasonal increase in productivity. Constant Effort Site (CES) data showed long-term (1984–2011) declines in four long-distance migrants and five resident species. However, four species (two short-distance migrants and two residents) have increased over the same period. Productivity of migrants monitored by CES was poor in 2012: seven of the eight species showed significant reductions in productivity compared to the five-year average and had the lowest productivity since CES began in 1983. Breeding performance of resident birds was low in 2012, with juvenile:adult ratios significantly lower than those calculated over the preceding five years for 10 of the 16 species. The number of CE sites increased in 2012, with data submitted for 125 sites, the highest total for a decade. The number of active RAS projects increased to 163 in 2012, with 21 new projects, eight of which involved RAS target species. In 2012 the total number of birds ringed (970,957) was the second highest recorded, and included 408,225 first-year birds, 377,199 adults (birds in their second calendar year or older), 23,772 unaged birds and 161,761 nestlings. In addition, there were 249,551 recaptures of ringed birds at or near the ringing site. The reduction in numbers ringed compared to 2012 was probably the result of the record wet weather that most of Britain & Ireland experienced in spring and summer 2012. A total of 18,693 BTO-ringed birds were recovered in 2012, which was lower than in 2011 but higher than in any previous year. This is the result of an increased number of birds ringed in the past 10 years, an increasing number of colour-ringed and tagged birds and subsequent resightings, more ringers within the Ringing Scheme, efforts to increase reports from members of the public of both metal and colour-ringed birds and an improvement in the way recoveries are processed. Recoveries of 22 BTO-ringed and 11 foreign-ringed individual birds that have extended our knowledge of movement of the species or constitute a new longevity record are presented. In total 44,895 nest records were submitted in 2012, the highest annual submission since the scheme began. Of these, 81% originated from England, 9% from Wales and 9% from Scotland, the remaining 1% divided equally between Northern Ireland and the Republic of Ireland. Submissions from England, Scotland and Northern Ireland have all risen by similar proportions since 2007 (18–22%), while those from Wales have increased by 34% over the same period. Long-term annual productivity trends have been calculated for three additional species. Long-term productivity trends were significant for 40 of the 72 species monitored and nine of these trends were negative, indicating a decline in breeding success over time. [ABSTRACT FROM AUTHOR]

Aim Recent, rapid population declines in many Afro-Palaearctic migratory bird species have focussed attention on changing conditions within Africa. However, processes influencing population change can operate throughout the annual cycle and throughout migratory ranges. Here, we explore the evidence for impacts of breeding and non-breeding conditions on population trends of British breeding birds of varying migratory status and wintering ecology. Location Great Britain (England & Scotland). Methods Within- and between-species variation in population trends is quantified for 46 bird species with differing migration strategies. Results Between 1994 and 2007, rates of population change in Scotland and England differed significantly for 19 resident and 15 long-distance migrant species, but were similar for 12 short-distance migrant species. Of the six long-distance migrant species that winter in the arid zone of Africa, five are increasing in abundance throughout Britain. In contrast, the seven species wintering in the humid zone of Africa are all declining in England, but five of these are increasing in Scotland. Consequently, populations of both arid and humid zone species are increasing significantly faster in Scotland than England, and only the English breeding populations of species wintering in the humid zone are declining. Main conclusions Population declines in long-distance migrants, especially those wintering in the humid zone, but not residents or short-distance migrants suggest an influence of non-breeding season conditions on population trends. However, the consistently less favourable population trends in England than Scotland of long-distance migrant and resident species strongly suggest that variation in the quality of breeding grounds is influencing recent population changes. The declines in humid zone species in England, but not Scotland, may result from poorer breeding conditions in England exacerbating the impacts of non-breeding conditions or the costs associated with a longer migration, while better conditions in Scotland may be buffering these impacts. [ABSTRACT FROM AUTHOR]

The article reports that figures from the British Trust for Ornithology's (BTO) Constant Effort Sites Scheme (CES) showed the increase in birds ringed in Great Britain in 2009. About 920,000 birds were ringed in 2009. The increase in the number of birds ringed is also attributed to the rise in the number of ringers who joined the scheme.