JUKEMA J, KLEEFSTRA R, POSTMA J, JUKEMA J & STIENSTRA D (2015) The Quail Coturnix coturnix year 2011 from a Frisian perspective. LIMOSA 88 (2): 96-99.

Quail numbers are known to fluctuate from year to year, with irregular irruptions of calling males. In the Netherlands, the irruption occurring in 1989 has been considered the largest on record. In the spring of 2011 another irruption took place.
In the agricultural region of Northwest Friesland, we have mapped calling Quails each year since 1997 in an area of 2184 ha of arable land with cereals, grass seed, potato and sugar beet (Fig. 1). In 1997-2010 0-3 calling males per year were noted, but in 2011 males were heard in 61 different fields within our mapping area. Also the provincial monitoring scheme for meadow birds showed higher numbers of calling Quails in comparison to previous years (Fig. 2). The national breeding bird index even showed the highest peak since the start of the monitoring scheme in 1984, suggesting that this irruption might have been larger than that of 1989 (Fig. 3). Quail invasions are frequently linked to warm and dry weather in spring. We indeed found that for the Netherlands mean temperature in May and June in Quail years was often slightly higher and mean precipitation slightly lower than in non-Quail years (Fig. 4). However, literature suggests that irruptions could also be triggered by conditions in Mediterranean breeding areas. Ringing data from the Netherlands and Germany indicate spring migration from southern Europe. There are no recaptures of ringed Quail suggesting migration from eastern to western Europe.

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