Table 3. Summary of environmental variables with significant effect on traits measured using linear regression models.

	Female Sex	Winter precipitation	Temperature maximum	NDVI	Altitude	Distance from Johannesburg	National road distance	Urban 2
Bill length	-							+|m(+)
Bill width			+|m(+)	+|f(+)
Bill depth	-							−|m(−)
Head	-					+|f(+)
Tail L.					+|m(+)	+|m(+)
Tarsus L.	-	−|m(−)			−|m(−)|f(−)
Wing length	-				+|m(+)|f(+)	+|f(+)
Wing loading	-				+|m(+)|f(+)	+|f(+)
HR	-			−|m(−)|f(−)
TR	-			−|m(−)	−|m(−)
BR	-			−|m(−)|f(−)	+|m(+)|f(+)
WTR	-	+|m(+)
Size	-						+|m(+)
Shape	-			+|f(m)	+|f(+)

Signs indicate positive or negative effects. Plain cells indicate that only interactions of the two factors have an effect. Each effect has been tested for females (f) and males (m) separately. +|m(+) : indicates a positive effect when both sexes combined (+|), when sexes were analysed separately only a positive effect was found in males (m(+)).