Long-term trends in abundance, phenology, and morphometrics of Little Stint Calidris minuta during autumn migration in southern Sweden, 1946–2020

The Little Stint Calidris minuta is an Arctic wader species that migrates through the Baltic Sea region towards wintering areas in North and West Africa Mediterranean region. We use a 75-year trapping series, comprising 4,791 Stints on autumn migration, from Ottenby Bird Observatory Sweden to illustrate long-term trends abundance, phenology, morphometrics. Numbers of trapped juveniles dropped median 31 (mean 74) 1946–1999 1.5 3.5) birds 2000–2020, while number adults was generally low without trends. Rolling window analyses showed drop started around 1984, 1993 onward never exceeded seven juveniles/year (25 %-quantile: 0–1; 75 4–55). Moreover, adult advanced their passage average 0.48 days per year, passing 26 earlier 2020 than 1946. Earlier migration decreased numbers suggest reproductive output recent decades. Morphometric data recaptured show stopover at gain fuel speed close theoretical maximum, strongly indicating conditions site remain favourable for foraging waders.