Measurements

Measurements (in mm) from authoritative sources for boreal S. m. maxima and for S. m. albididorsalis in Appendix 1, and only published measurements known for austral S. m. maxima in Appendix 2 . Perhaps most outstanding inadequacy more extensive sets of complete measurements for austral S. m. maxima and for S. m. albididorsalis, deficiencies begging rapid correction. In boreal S. m. maxima, no consistent geographic variation in measurements even between allopatric populations (Atlantic coast, Gulf coast, West Indies, Baja California); no data on within-population variation in austral S. m. maxima, and owing to small sample sizes, only study to date (Escalante 1985) unable to find consistent differences when austral compared to boreal breeders. In all populations currently considered, males weigh more and are larger than females in all measurements; juveniles especially have conspicuously smaller bills than adults (Cramp 1985, Malling Olsen and Larsson 1995).

In boreal S. m. maxima, adult males 390 g in Apr, 475 g in Jan; adult females 300 g in Nov, 346 g in Dec, 415 g in Feb, 449 g in Aug; 2 second-calendar-year females 368 g and 385 g in May, 390 g in Jul; third-calendar-year males 500 g in Jan, 430 g in May (Cramp 1985); adult males 390–475 (sample size not given), adult females 300–585 g (Malling Olsen and Larsson 1995). No austral S. m. maxima data. For S. m. albididorsalis, means of 22 adults, 367 g (range 350–395); 28 “immatures,” 353 g (range 310–410); 13 juveniles, 341 g (range 320–360; Cramp 1985); 4 “adults” aver-aged 324 g (range 308–345; Urban et al. 1986); (sample size not given) adults, 350–440, 28 “immatures” averaged 353 g (range 310–410), 13 juveniles 341 g (range 320–360; Malling Olsen and Larsson 1995). Boreal S. m. maxima strikingly heavier than S. m. albididorsalis in all age groups and this probably taxonomically significant. For chick data, see Breeding: young birds, above.