Table 6. Incidence-controlled down-sampling strategy used in study of of terrestrial bird migration and WNV circulation, United States*.

Location, year	WNV incidence	Sequences available	Sequences used
GA
2001	7.16 × 10−7	5	3
2002	3.29 × 10−6	11	6
2003	3.13 × 10−6	1	1
2004	1.60 × 10−6	2	2
2005	1.01 × 10−6	1	1
2006	2.18 × 10−7	0	0
2007	2.46 × 10−6	5	5
2008	4.21 × 10−7	3	3
2009	4.16 × 10−7	3	3
NY
2001	6.81 × 10−7	10	3
2002	3.55 × 10−6	10	6
2003	2.97 × 10−6	15	5
2004	3.65 × 10−7	10	3
2005	1.57 × 10−6	7	4
2006	8.37 × 10−7	5	3
2007	8.36 × 10−7	9	3
2008	1.67 × 10−6	18	4
2009	3.11 × 10−7	2	2
VA
2001	0	6	2
2002	2.20 × 10−6	10	5
2003	2.58× 10−6	6	5
2004	6.69 × 10−7	4	3
2005	0	3	2
2006	0	4	2
2007	3.87 × 10−7	2	2
2008	0	4	2
2009	6.31 × 10−7	5	3

*The numbers of West Nile virus sequences available and of sequences used in the down-sampled dataset are summarized. WNV, West Nile virus.