The effects of regional weather patterns on the migration of birds and Lepidoptera to a coastal migration “hotspot” in East Kent and possible changes in occurrence in response to global climate change

The phenomenon of long-distance migration is an important strategy for the survival of many species by maximising chances of breeding success in different climates. By analysing past literature covering the effects of weather on migration, a research gap was found that related to understanding between categorised, localised weather patterns on the migration of three groups: migratory breeding birds, vagrant birds and migratory moths and how climate change could affect the weather patterns and hence migration to the UK. Using long term-data (30 years – 1990–2020) provided by the Met Office and Sandwich Bay Bird Observatory (a site on the southeast coast of England), notable dates of migration and records of unusual species were compiled, as well as the corresponding weather patterns. ANOVA tests were undertaken to identify which weather patterns were linked to migration events in the three species groups. Correlations were used to determine if the rate of migrant moths and vagrant birds was changing over time and if the weather patterns that were favoured for migration were changing in frequency. There was an increase in the number of migratory moths and vagrant bird species annually over the study period, with ten weather patterns being favoured by all three species groups. Notably, for several migratory birds, such as pied flycatcher and redstart, there were shifts in the arrival and departure dates, possibly linked with climate-change. Three weather patterns linked to migration showed major trends in frequency over the period of investigation. This implies that there were subsequent factors such as population change or changes in climate driving increases in vagrancy/migration. In conclusion, the research shows that there has been an upward trend in the occurrences of vagrant bird species and migratory moth species, despite little evidence of weather patterns changing. Recommendations from the study include the incorporation of a longer study-period and other sites, to identify if these trends are more widespread