Records

222. Burke Museum nest record cards=211 (class cards=37); egg sets=11.

Counties

Benton=156; Douglas=6; Grant=4; King=50; Okanogan=1; Pierce=1; Spokane=1; Walla Walla=1; Whatcom=2; Whitman=2.

First-egg dates

Earliest 10 March (Julian day 69); latest 27 May (Julian day 147).

Essentially all records are for lowlands. The initiation of nesting seems more drawn out in western than eastern Washington, especially given the large difference in sample size. Consequently the median first-egg date is more than two weeks earlier in eastern than western Washington (p<0.001). For eastern Washington the median first-egg date is 28 March (Julian day 87); for western Washington it is 13 April (Julian day 103).

Clutch size

154 usable records. Statewide mean 5.59 eggs. Distribution: 2-13 eggs. Canada Geese are sometimes conspecific brood parasites (Rohwer and Freeman 1989), so the clutches of 9 or more eggs were likely laid by more than one female.

Season and clutch size

Clutch size decreases by 2.1 eggs over the 78 day season of nest initiation (Y = 8.06 –0.03X; r2=0.063; p=0.002).