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ABSTRACTBiometrics are commonly used to compare bird species. For Marsh Tits and Willow Tits in Britain there are few biometric data from birds of known age and sex, despite their value for population analyses in estimating the proportion of males and females in samples. Comparing measurements between the two species could also aid identification and the monitoring of these declining species in Britain. We present biometrics for a large sample of Marsh Tits of known age and sex, and new data for Willow Tits, which act as reliable reference material. Overall, adults of both species were larger than first-years and males were larger than females, but not among first-year Willow Tits. Marsh Tits were slightly larger and heavier than Willow Tits, but Willow Tits had proportionately longer tails. Discriminant analyses produced new equations for separating the species based on wing length and the measurement between the shortest and longest tail feathers. Probabilities were generated for estimating Marsh Tit population structure from samples of ringing data, but there was a greater overlap between sexes in Willow Tit measurements. We conclude by discussing issues of measurement accuracy and consistency in the collection and analysis of biometric data.

This is the 76thannual 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.

This is the 75thannual report of the British Trust for Ornithology's Ringing Scheme, covering data received and work carried out in 2011. A review of priorities for the Scheme identified the need to increase submission of nest records through the Nest Record Scheme and to extend the network of Retrapping Adults for Survival (RAS) studies. Collection of different demographic parameters from the same site (egnest records, numbers of breeding pairs, adult survival, etc) can provide a powerful tool to identify reasons for population change. Constant Effort Sites (CES) data showed long-term declines in abundance for four migrants (Willow Warbler Phylloscopus trochilus, Lesser Whitethroat Sylvia curruca, Sedge Warbler Acrocephalus schoenobaenusand Reed Warbler Acrocephalus scirpaceus) and three resident species (Willow Tit Poecile montana, Song Thrush Turdus philomelosand Reed Bunting Emberiza schoeniclus). Robin Erithacus rubeculaand Reed Bunting had the lowest survival rates since CES began and survival-rate estimates were also significantly below average for Long-tailed Tit Aegithalos caudatusand Wren Troglodytes troglodytes, two small resident species that are particularly vulnerable to cold weather. Abundance of Blue Tit Cyanistes caeruleus, Great Tit Parus major, Goldfinch Carduelis carduelisand Bullfinch Pyrrhula pyrrhularecorded by CES increased. Nine of the 16 resident species covered by CES also had higher-than-average productivity, in particular the highest ever recorded for Dunnock Prunella modularis, Chaffinch Fringilla coelebsand Bullfinch. The number of Constant Effort Sites increased in 2011, with a higher percentage of reedbed habitat covered by the scheme, but fewer dry and wet scrub sites. In 2011 the number of RAS projects increased by 34 to 158. Survival trends were generated for 46 species and the use of colour marks has been promoted to increase the resighting probability of trap-shy species such as House Sparrow Passer domesticusand Starling Sturnus vulgaris, and for species with low recapture probability such as seabirds. As in 2010, the total number of birds ringed in 2011 (1,151,665) was the highest ever. It included 540,696 first-year birds, 383,136 adults (birds in their second calendar year or later) and 27,495 unaged birds. All ringing data for 2011 were computerised. In addition, there were 166,061 recaptures of ringed birds at or near the ringing site. The increased numbers of fully grown birds ringed is probably due to three main factors: high survival of some species, as suggested by CES results, combined with high productivity in 2011 and the increasing number of ringers in the Scheme catching higher numbers of birds. In total 20,702 BTO-ringed birds were recovered (found dead or recaptured away from the ringing site) in 2011, the highest ever as a result of the increased number of birds ringed in the past decade, combined with efforts to increase reports of ringed birds by the public, an increasing number of colour-ringing projects and associated resightings, and a change in the way recoveries are processed. Recoveries of 17 BTO- and 13 foreign-ringed birds that have extended our existing knowledge of movements of a species, are unusual movements, or are a new longevity record are also presented. In 2011 40,845 nest records were submitted (over 70% electronically), the highest total since 1998. Of these, 82% originated from England, 9% from Wales and 8% from Scotland, with the remaining 1% divided equally between Northern Ireland and the Republic of Ireland. Long-term nest productivity trends (1966–2010) were significant for 36 of the 71 species for which sufficient data were available, and seven of these (Nightjar Caprimulgus europaeus, Tree Pipit Anthus trivialis, Willow Warbler, Bullfinch, Coal Tit Periparus ater, Treecreeper Certhia familiarisand Chaffinch) showed a significant decline over time. The 2011 breeding season was characterised by an early start compared to the previous five years, possibly due to the warmest April on record.

This is the 74th annual report of the British Trust for Ornithology's Ringing Scheme, covering data received and work carried out in 2010. Analytical work in the year concentrated on considering how we can improve demographic monitoring, an increasing focus for the Scheme. A broad review of the availability of demographic and count data for terrestrial-breeding species was carried out. This work will be further extended in 2011. To inform conservation we need to build population models for species with a range of ecologies and occupying different habitats. Reports of ringed birds make a large contribution to our understanding of two key demographic parameters – survival and dispersal. An analysis of Chiffchaff Phylloscopus collybitarecovery data from across Europe suggested they are tending to migrate south later and north earlier over time. There is also a suggestion that the migratory journey is shortening. Analysis of biometrics of birds wintering in Britain showed that they are largely from the breeding populations of the nominate race in Britain and the near Continent. Constant Effort Sites (CES) data showed that, for seven of the 24 species monitored, there was a significant decrease in adult abundance compared to the mean of the previous five years. As six of these species were residents, this may have been a result of the second severe winter in succession, although there was a short-term increase for Long-tailed Tit Aegithalos caudatus, which is usually affected by cold winters. The adult abundance of several long-distance migrants also increased. A long-term decline (1984–2000) is, however, still evident for five migrants and three residents, although for Willow Tit Poecile montanaand Linnet Carduelis cannabinathe sample sizes are low. The abundance of the short-distance migrants, Blackcap Sylvia atricapillaand Chiffchaff, has increased, possibly as a result of climate change. Productivity was higher than the mean of the previous five years for 12 species with the long-term trend increasing for eight species – four migrants and four residents. The only significant decreases were for Blackbird Turdus merulaand Long-tailed Tit, possibly as these species breed early and were affected by the severe winter. Dry summer weather is also likely to have contributed to the low productivity of Blackbirds and increasingly dry summers may be implicated in the long-term declines in productivity for both Blackbird and Song Thrush Turdus philomelos. Long-term trends in survival rates were produced using CES data for the first time in 2010. These suggested that the cold winter weather in 2009–10 reduced the survival rate of resident ground-feeding insectivores such as Dunnock Prunella modularis, Blackbird, Wren Troglodytes troglodytesand Robin Erithacus rubecula. Survival rates of migrants were relatively high, particularly for Garden Warbler Sylvia borinand Sedge Warbler Acrocephalus schoenobaenus, possibly as a result of good conditions on the wintering grounds or passage sites. Data for 129 Retrapping Adults for Survival (RAS) studies covering 39 species were submitted. For the first time we were able to calculate good or moderate annual estimates of survival for 18 species. A list of priority species for RAS was developed and promoted to volunteers. The total number of birds ringed (1,096,533) was the highest ever recorded, as well as being the first time the annual total has surpassed 1 million. It was 28% higher than the mean of the previous five years and 17% higher than in 2009. However, the total number of pulli ringed in 2009 (193,554) was only 12% higher than the preceding five-year mean, while that of fully grown birds (902,979) was 32% higher. The recovery total (17,315) was also the highest ever. This is partly due to changes in the way that records of colour-ringed and other specially marked birds are stored, but also reflects the increasing number of birds being ringed by a growing number of ringers. The number of recoveries of foreign-ringed birds (2,427) was higher than the mean of the preceding five years; this figure was influenced by varying response times of different ringing schemes, but was also partly as a result of multiple sightings. Recovery details for 221 individual birds are given in the final section of the report. They include movements that confirm suspected or known migration patterns, unexpected movements and longevity records.