Measurements

Study of geographic variation of populations from Northern Prairies to MacKenzie River Delta showed cline of decreasing bill length and wing length (small difference) for both sexes from south to north; no difference in tail length (Raveling and Warner 1978). Linear measurements from Raveling and Warner 1978 unless referenced otherwise.

Wing Length

Measurements are for flattened wing from wrist to tip of longest primary. Males, Northern Prairies (s. Saskatchewan, s. Manitoba), mean 64.2 mm ± 2.11 SD (range 59–68, n = 61); MacKenzie River Delta, mean 61.9 mm ± 1.53 SD (range 60–65, n = 18). Females, Northern Prairies, mean 61.1 mm ± 1.47 SD (range 59–64, n = 24); MacKenzie River Delta, mean 58.0 mm (range 57–59, n = 3). For males of D. p. sonorana of sw. U.S., male wing chord averages 63.1 mm (range 61.0–65.7, n = 14; Browning 1994).

Tail Length

Measured from base of center feathers to tip. Tail length relatively uniform among all samples from Northern Prairies to MacKenzie River Delta. Male mean 45.1 mm (n = about 126); females, mean 43.3 mm (n = about 66).

Bill Length

Measured from anterior edge of nostril to tip. Males, Northern Prairies (s. Saskatchewan, s. Manitoba), mean 8.02 mm ± 0.31 SD (range 7.3–8.8, n = 60); MacKenzie River Delta, mean 7.50 mm ± 0.28 SD (range 7.0–7.9, n = 16). Females, Northern Prairies, mean 7.89 mm ± 0.23 SD (range 7.3–8.6, n = 22); MacKenzie River Delta, mean 7.40 mm (range 7.1–7.8, n = 3). Browning (1994) gives bill measurements for males of 3 northern North American subspecies: D. p. parkesi, mean 7.55 mm (range 6.9–7.9, n = 24); D. p. rubiginosa, mean 8.29 mm (range 7.6–8.6, n = 10); and D. p. banksi, mean 7.84 mm (range 7.5–8.3, n = 11).

Mean mass, males: 10.0 g ± 0.6 SD (n = 178); females: 9.6 g ± 0.8 SD (n = 140), for period 21–27 May at Delta Marsh, Manitoba (Biermann and Sealy 1985). Extensive data taken 1976–1982 demonstrate seasonal dynamics of mass on breeding grounds (Biermann and Sealy 1985): Male mass generally constant for first 10 wk of breeding then increases for final 5 wk prior to migration (weekly means range from 9.9–10.4 g); female mass initially drops after arrival, increases during egg-laying and incubation, then drops and gradually returns to their arrival value after young become independent in Jul (weekly means range from 9.6–10.9 g). Males generally heavier than females except during egg laying and incubation phase of breeding season; older (ASY) birds, both males and females, heavier than younger (SY) birds; some statistical variation due to year of measurement. At James Bay, Ontario, peak mean body mass of both sexes coincided with periods of greatest intensity of flight feather and body molt, and progressively declined during late stages of molt (Rimmer 1988).