Table 1.

Sample sizes and prevalence of detected influenza antibodies or viral RNA in samples from ducks collected in the San Francisco Bay Estuary, California during winters of 2017–2018 and 2018–2019. All samples included in this table also included paired mercury data. Confidence intervals (CI) are derived from 10 000 bootstrapped samples.

common name	scientific name	antibody sample size (ELISA)	antibody prevalence [95% CI]	active infection sample size (rRT-PCR)	active infection prevalence [95% CI]
American green-winged teal	Anas crecca carolinensis	11	0.36 [0.09, 0.64]	89	0.08 [0.03, 0.13]
American wigeon	Mareca americana	22	0.50 [0.27, 0.68]	64	0.05 [0.00, 0.11]
canvasback	Aythya valisineria	70	0.84 [0.74, 0.91]	65	0.05 [0.00, 0.11]
cinnamon teal	Anas cyanoptera	7	0.71 [0.29, 1.00]	15	0.13 [0.00, 0.33]
gadwall	Mareca strepera	17	0.59 [0.35, 0.82]	33	0.03 [0.00, 0.09]
greater scaup	Aythya marila	24	0.83 [0.67, 0.96]	24	0.04 [0.00, 0.12]
lesser scaup	Aythya affinis	86	0.77 [0.67, 0.86]	88	0.09 [0.03, 0.16]
mallard	Anas platyrhynchos	50	0.80 [0.68, 0.90]	90	0.04 [0.01, 0.09]
northern pintail	Anas acuta	28	0.79 [0.64, 0.93]	61	0.08 [0.02, 0.15]
northern shoveler	Spatula clypeata	26	0.88 [0.73, 1.00]	89	0.11 [0.04, 0.18]
ruddy duck	Oxyura jamaicensis	96	0.65 [0.55, 0.74]	102	0.06 [0.02, 0.11]
total/mean		437	0.74 [0.70, 0.78]	720	0.07 [0.05, 0.09]