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This is the 85th 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 2021. In 2021, 105 Constant Effort Sites submitted data for the year. Long-term (1984–2020) declines in abundance were observed for five migrant, one partial migrant and five resident species, while long-term increases in abundance were recorded for two short-distance migrants and seven resident species. Ten species are exhibiting significant long-term declines in productivity, while only Chaffinch Fringilla coelebs shows a significant long-term increase. Long-term trends in survival indicate increases for 12 species and declines for seven. Short-term trends, which compare the current year to the five-year mean for 2016–20, show that the abundance of seven species increased significantly in 2021, with one species, Treecreeper Certhia familiaris, being recorded in higher numbers than in any previous year of CES monitoring. Significant decreases in abundance were recorded for four species. Productivity decreased significantly for seven migrant and 11 resident species in 2021, with six species recording their lowest breeding success since CES monitoring began; no species recorded a significant short-term increase. Significant changes in survival rate were observed for two species in 2021 compared to the five-year mean, with Song Thrush Turdus philomelos increasing and Chaffinch both declining and recording its lowest survival rate ever. The Garden CES trial continued in 2021, with 60 sites submitting data. The new winter ringing project also continued in 2021, with submissions received from 126 sites. The number of Retrapping Adults for Survival projects that were able to run and submit data in 2021 was 192, with data from one more project submitted too late to be included in this report and another four active projects unable to operate. In total, 60 species were monitored, with Starling Sturnus vulgaris (21 projects), House Sparrow Passer domesticus (20 projects), Pied Flycatcher Ficedula hypoleuca (19 projects), Reed Warbler Acrocephalus scirpaceus (nine projects) and Sand Martin Riparia riparia (nine projects) the species most studied. A total of 900 131 birds were ringed during the year, comprising 146 458 nestlings, 438 342 first-year birds, 291 127 adults (birds in their second calendar year or older) and 24 204 birds whose age could not be determined. In addition, there were 210 147 recaptures of ringed birds at or near the ringing site. In total, 42 328 recoveries (birds found dead, recaptured or resighted at least 5 km from the place of ringing) of BTO-ringed birds were reported in 2021. The Appendix highlights a selection of recoveries that have extended our knowledge of movements, as well as longevity records established during the year. A total of 41 096 NRS submissions were received in 2021. Mean laying dates for 2021 were significantly later than the average for 13 species and only one species significantly advanced its laying date. Five species displayed a significant change in fledglings per breeding attempt, with two recording increased productivity and three reduced productivity. Permits or licences to disturb breeding birds on Schedule 1 of the Wildlife and Countryside Act 1981 (as amended) were prepared and issued to 602 ringers and nest recorders in 2021. During 2021, 2588 marking endorsements, 868 sampling endorsements and 214 trapping endorsements were issued in the UK and overseas. [ABSTRACT FROM AUTHOR]

This is the 84th 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 2020. An analysis of Curlew Numenius arquata ringing records was carried out to investigate recent declines. Results showed that survival rates are high, so current population declines are more likely to have been driven by low productivity. To reverse the recent population declines, breeding success would need to increase and effective conservation strategies will be needed to maintain the high levels of survival. We examined the potential opportunities and challenges of using winter ringing records to produce survival estimates, as well as other outputs such as age ratios and recruitment, by analysing 2 641 352 encounter records from the winters of 2007/08 to 2017/18: winter-to-winter survival analyses on adult birds were undertaken, initially on 44 species. Results indicated that fortnightly ringing sessions should yield sufficient data to produce useful survival estimates. This research identified a number of potential analytical and methodological options for future development. Covid-19 restrictions limited the amount of fieldwork carried out in 2020; consequently, only 72 CE sites submitted data for the year. Long-term (1984–2019) declines in abundance were observed for five migrant, one partial migrant and four resident species while long-term increases in abundance were recorded for two short-distance migrants and six resident species. Six species are exhibiting significant long-term declines in productivity while only Chaffinch Fringilla coelebs shows a significant long-term increase. Long-term trends in survival indicate increases for 10 species and declines for nine. Short-term trends, which compare the current year to the five-year mean (2015–19), show that the abundance of 10 species increased significantly in 2020, with three species being recorded in higher numbers than in any previous year since CES monitoring began. Significant decreases in abundance were recorded for only two species. Productivity decreased significantly for one migrant and five resident species in 2020; no species recorded a significant increase. Productivity was lower in 2020 than in any previous CES year for Blue Tit Cyanistes caeruleus and Great Tit Parus major. Significant changes in survival rate were observed in two species in 2020 compared to the five-year mean, with Bullfinch Pyrrhula pyrrhula increasing and Blackbird Turdus merula decreasing. A new habitat was added to the suite of standard CES habitats in 2020 in the first year of a Garden CES trial. Submissions were received from 92 sites. A new winter ringing project was also launched in 2020, following a similar methodology to CES. Submissions were received from 111 sites. The number of Retrapping Adults for Survival projects that were able to run and submit data in 2020 was 146, from 200 that were registered. In total, 60 species were monitored, with Pied Flycatcher Ficedula hypoleuca (20 projects), Starling Sturnus vulgaris (19), House Sparrow Passer domesticus (18), Sand Martin Riparia riparia (10) and Reed Warbler Acrocephalus scirpaceus (eight) the species most studied. A total of 930 091 birds were ringed during the year, comprising 98 500 nestlings, 523 777 first-year birds, 278 157 adults (birds in their second calendar year or older) and 29 657 birds whose age could not be determined. In addition, there were 212 414 recaptures of ringed birds at or near the ringing site. In total, 42 987 recoveries (birds found dead, recaptured or resighted at least 5 km from the place of ringing) of BTO-ringed birds were reported in 2020. The Appendix highlights a selection of recoveries that have extended our knowledge of movements, as well as longevity records established during the year. A total of 23 928 NRS submissions were received in 2020, far fewer than usual due to Covid-19 restrictions being in place during the height of the nesting season. As the seasonality of nest records was biased towards the end of the breeding season, after Covid-19 restrictions had lifted, it was not possible to generate meaningful NRS trends for 2020. Permits or licences to disturb breeding birds on Schedule 1 of the Wildlife and Countryside Act 1981 (as amended) were prepared and issued to 611 ringers and nest recorders in 2020. During 2020, the use of special methods was authorised for 1182 marking projects and 146 trapping projects. [ABSTRACT FROM AUTHOR]

Many hirundine (swallows and martins) species are declining throughout their ranges. The Common House Martin Delichon urbicum is a migratory hirundine that breeds throughout Europe but has shown recent declines in some parts of the UK, particularly in the south. We conducted a large‐scale citizen science survey to assess how the breeding performance of House Martins, measured by the number of attempted broods and nest success, is influenced by nest‐specific, landscape and weather factors. Pairs in eastern parts of the UK started breeding earlier than those in the west, and breeding performance was higher in eastern regions. There was no effect of latitude on either aspect of breeding performance, so our measures of breeding performance alone do not help to explain differences in population trends across the UK. The probability of attempting multiple broods and producing successful nests was higher in previously used nests than in newly built nests, and in artificial nests than in natural nests. Nests built on plastic soffits of buildings were less likely to be multi‐brooded and less likely to be successful compared with other materials. Suggested conservation measures therefore include discouraging the removal of old nests and encouraging the installation of artificial nests, particularly on buildings with plastic soffits. This study provides comprehensive insight into the breeding biology of House Martins, and although our findings do not show conclusively that breeding performance is the sole driver of population trends, they go some way to explain declines in House Martins and ultimately provide information that may help conserve this species. [ABSTRACT FROM AUTHOR]