Long-term trends in the nest survival and productivity of the Lesser Spotted Woodpecker Dryobates minor in Britain

Abstract

ABSTRACT Capsule: There has been no trend in nest survival of Lesser Spotted Woodpecker Dryobates minor in the 70 years since the 1940s whereas the numbers of young per nesting attempt has declined. Late nests in any year are now significantly less productive than early ones. Aims: To test whether there has been a long-term decline in the nest survival and productivity of the Lesser Spotted Woodpecker in Britain. Methods: Breeding data from 331 nests over the period 1949–2019 have been analysed. There were three sources – nest records submitted to the British Trust for Ornithology, a study by the Royal Society for the Protection of Birds from 2006 to 2009 and records submitted to the Woodpecker Network from 2015 to 2019. Generalized linear models were used to analyse the records for first egg date, clutch size, numbers of young fledged, and numbers of nest days for which the nest was under observation. Data were grouped into three periods reflecting population trends of the bird (pre-1980, 1980–1999, 2000–2019) and we also analysed trends with year and spring temperature. Results: There was no trend in first egg date up to 1980 but subsequently it has advanced by 13 days. The mean clutch was 5.3 with no trend with period or year. There were no trends in nest survival during the egg stage or chick rearing. The mean number of young fledged was 2.6, with nests since 1980 fledging lower numbers of young than those pre-1980 and a decline with year. Loss of chicks, probably to starvation, was the main cause of low productivity. In the last period (2000–2019) nests started early in the season fledged more young than those started later, a trend not apparent in the earlier periods. Conclusions: Low productivity is a widespread problem for the Lesser Spotted Woodpecker which has probably been exacerbated by the trend towards warm springs.