Discussion

Despite various uncertainties, the apparent progressive nature of the arrival is one of the most remarkable aspects of this influx. Had no more birds arrived after the end of June it would already have been a very good, if not record breaking, “Quail year”. Little did we realise that the main influx was still en route at that stage. It is known from the literature [6,7], based on observations of migrant flows in Mediterranean regions, that this species can exhibit a unique inter-season migration (“Zwischenzug”), with some birds breeding in southern Europe, but then departing again only to settle further north and undertake further breeding activity. Others merely take a territory and call for a few days, then failing to attract a mate move on perhaps 100’s of kilometres north. There is some indication that the sex ratio is heavily biased in favour of males at more northern locations [7]. In these instances our ability to detect them will be much greater, since the calling output of paired individuals is known to be very low in comparison, and this may be a factor contributing to the high numbers recorded. Further waves of migrants are also thought to include fresh juveniles, with first broods capable of migrating just two months after hatching and sexually mature at 3 to 4 months [8]. So another factor in this record influx may have been an exceptional breeding productivity earlier in the year much further south.

Despite the large numbers recorded, we remain very uncertain as to the overall extent of the influx, and the totals presented may still be highly conservative. A lot of the picture uncovered seems to have depended upon being in the right place at the right time. Quail are thought to all but cease calling once paired [6,7], and use of quieter vocabulary between a pair was noted at Coates [5]; their calling output may also vary quite markedly during the day, with a suggestion of peaks at dawn and dusk [5]. Only a single was heard calling during 6 hours of daytime TTV visits in tetrads around Coates (NT47S/T/Y) on 24 June (hence any deduction of breeding densities from TTV records might be hugely conservative!) and repeat visits along parts of the route where so many were recorded on 4 July produced none on the evening of 9 July or at dawn on 23 July.

Quail may also move around, with a suggestion in the literature of initial clustering followed by dispersal to surrounding areas [6]. With a secondary wave of arrivals it would make sense if these were drawn into areas where breeding birds were already holding territory, producing further temporary peaks of calling and activity. It is a bit of a mystery precisely how Quail find their breeding areas, and how traditional sites are maintained, particularly since annual mortality is thought to be as high as 80% with a near complete turn-over of the population every couple of years [7]. But who knows, perhaps the 11 birds calling at Coates on 18 July included some males which had already abandoned territories further south, either in Britain or beyond, or even fresh juveniles arriving from their natal areas in the Mediterranean, which had dropped down into the zone whilst passing over on their nocturnal migration in the immediately preceding days?! The latter may be far-fetched but the fact that we cannot say for certain anything better than this just goes to show how little we yet know about this fascinating species.

Acknowledgements

Many thanks to all who shared valuable information on Quail records, including those tireless workers specifically mentioned in the text and all others who contributed records. Ian Andrews developed the maps for the South-east Scotland bird atlas. Photo credits to Abbie Marland and George Hogg.

References

1. Smith, G.D. & McGarry, O. 1990. “Influx of Quail in Lothian 1989”, Lothian Bird Report 1989, Lothian Branch, Scottish Ornithologists’ Club.
2. Murray, R.D., Holling, M., Dott, H.E.M. & Vandome, P. 1998. The Breeding Birds of South-east Scotland, A Tetrad Atlas 1988-1994, The Scottish Ornithologists’ Club. http://www.the-soc.org.uk/se-atlas/
3. Bird Atlas 2007-11, BTO. http://www.bto.org/birdatlas/
4. Welch, S. 2010. “The influx of Quail to East Lothian in 2009”. Scottish Birds 30: 147-152.
5. Marland, A. 2010. “East Lothian Quail – a study in miniature”. Scottish Birds 30: 153-156.
6. Cramp, S. & Simmons, K.E.L. (eds) 1980. The Birds of the Western Palearctic. Vol. 2. Oxford University Press, Oxford.
7. Mur, P. 1994. “Contribution to the management of the Palearctic populations of European Quail in the European phase of its annual cycle”, PhD Thesis, University of Rennes I – France.
8. Balmer, D. “Quail – the Painted Lady of the bird world?”, BirdGuides webzine article, 19 July 2009 http://www.birdguides.com/webzine/article.asp?print=1&a=1690