Migration strategy of white-spotted bluethroats (Luscinia svecica cyanecula and L. s. namnetum) along the eastern Atlantic route

• The bluethroat Luscinia svecica is a particularly interesting species for the study of the mechanisms that control migration because it comprises several recently diverged subspecies that differ in migratory distance and direction. Here we use ringing data to describe the migration strategy and winter distribution of L. s. cyanecula and L. s. namnetum along the eastern Atlantic coast of Iberia and West Africa. No differences were found in autumn migration phenology between subspecies, ages and sexes. However, in contrast to L. s. namnetum, the mean wing length of L. s. cyanecula decreased and its body mass increased during this migratory period. The subspecies also differed in migration speed and stopover behaviour, with L. s. cyanecula travelling faster and refuelling during stopovers. The potential non-stop flight range was greater in L. s. cyanecula and increased with decreasing latitude, which is probably related to the need to overcome geographical barriers to reach the wintering grounds. During winter, the birds captured in sub-Saharan Africa were almost exclusively L. s. cyanecula, whereas L. s. namnetum wintered mainly in Iberia, and the probability of capturing adults increased with decreasing latitude. L. s. cyanecula captured in Africa had longer wings than those migrating through and wintering in Iberia, indicating a leapfrog migration pattern also within L. s. cyanecula populations.

Subject headings

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Keyword

migration

bluethroat

stopover ecology

wintering

Publication and Content Type

art (subject category)

ref (subject category)