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| The phenology of avian migration appears
to be changing in response to climate change. Seemingly
contradictory diVerences in the timing of these
annual cycles have been reported in published studies.
We show that diVerences between studies in the choice
of songbird species, as well as in the measurements of
migration phenology, can explain most of the reported
diVerences. Furthermore, while earlier spring arrival is
evident across these studies, trends in timing of departure
show large variation between species and according
to individual timing of migration (early-arriving vs.
late-departing individuals). Much of the variation in
departure between species could be explained by each
species’ migratory status. We present a detailed analysis
of migrants recorded at a Danish migration site, and
reveal that although shifts in migration timing can be
demonstrated for almost all species, these shifts are
either most pronounced in the early arriving/late
departing individuals or the changes are similar. Thus
most individuals do not seem to change their breedingarea
residence time (BART). As BART is likely to
reXect ecologically important factors, e.g. number of
clutches, we expect that only small eVects have been
exerted on the breeding ecology of the studied species
in the time period investigated. | |
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