Table 2.

Frequency of representative species appearing on checklists per year reported to eBird during the 1998–2002 and 2007–2009 periods

Species	1998–2002	2007–2009
Herons
Least Bitterna	0.05	0.01
Great Blue Heronb	0.71	0.76
Black-Crowned Night-Herona	0.43	0.38
Green Herona	0.39	0.27
Shore birds
Black-Necked Stilta	0.74	0.79
American Avocet	0.67	0.73
Spotted Sandpiper	0.26	0.25
Reed beds
Red-Winged Blackbird	0.59	0.44
Yellow-Headed Blackbird	0.16	0.14
Great-Tailed Grackleb	0.61	0.53
Controls
House Fincha	0.41	0.37
Brewer’s Blackbirda	0.32	0.21
For all species
No reports	148	397
No total species/taxa	269	294
No species reports	3,667	5,093

Reports per week for the sampling period were summed and standardized by the number of total reports.

^aFed on during both surveys.

^bFed on only during 2007–2009 survey.