LENSINK R & PILZECKER J (2021) Are the timing of arrival and departure of Barn Swallow Hirundo rustica in the Netherlands correlated?. LIMOSA 94 (4): 163-168.

Annual phenology data (first observation, median of all first observations) suggest an earlier arrival of the Barn Swallow Hirundo rustica near Arnhem, with an advance of about ten days between 1980 and 2005 (Fig. 1). Visual counts of early morning autumn migration near Arnhem also suggest an earlier departure between 1982 and 2003 of about ten days between 1980 and 2005 (Fig. 3). The timing of arrival in spring and departure in autumn show a strong correlation, suggesting a fixed duration of stay of about five months in the Netherlands.

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