Table 1

Average (s.e.m.) morphological data for black-capped chickadees collected at five locations along a gradient of environmental harshness. (Locations ranked by climate severity from harsh to mild.)

locationbody mass (g)wing length (mm)brain mass (g)absolute hippocampal volume (mm3)absolute number of hippocampal neurons (×106)telencephalon volume (mm3)relative hippocampal volume (mm3)arelative number of hippocampal neurons (×106)adates collected (2007)
Fairbanks, AK11.37 (0.17)65.88 (0.70)0.77 (0.01)28.15 (0.87)1.952 (0.161)494.26 (15.55)28.38 (0.85)2.030 (0.128)18–20 Sept
Prince George, BC10.87 (0.17)67.05 (0.64)0.80 (0.02)26.60 (0.82)1.877 (0.126)502.61 (21.94)27.04 (0.98)2.013 (0.148)29 Sept to 1 Oct
Missoula, MT11.42 (0.30)65.83 (0.58)0.73 (0.02)25.07 (0.77)1.735 (0.104)446.90 (21.90)25.19 (0.85)1.745 (0.128)10 Oct
Fort Collins, CO11.65 (0.19)67.19 (0.42)0.76 (0.01)25.03 (0.87)1.727 (0.115)485.82 (11.84)25.04 (0.79)1.736 (0.120)15–17 Oct
Manhattan, KS12.84 (0.24)69.15 (0.73)0.74 (0.02)23.15 (0.63)1.578 (0.098)459.10 (14.91)22.50 (1.01)1.393 (0.153)21–23 Oct
  • a Least-squares means values calculated from a GLM analysis using telencephalon and body mass as covariates.