Figure 2. Variation in the behavioral responses of territorial white-throated sparrows to same-morph and opposite-morph male intruders.

(a–b) Vocal behaviors of resident tan-striped (TS; n = 17) and white-striped (WS; n = 14) males. (c–e) Physical behaviors of resident TS (n = 14) and WS (n = 17) females. Values are means ± SE, and P-values are from WSR tests used to compare responses to same-morph intruders with those toward opposite-morph intruders.