Bill morphology and biometrics of three sibling woodpecker species from sympatric populations

Figures & data

Figure 1. Image of a woodpecker bill with semi-landmarks shown. A – Dorsal view and B – Lateral view. Red points are landmarks, white points are semi-landmarks digitized along the curves.

Figure 2. Results of PCA of bill shapes for the dorsal view. Grey lines represent bill shape for the principal component.

Figure 3. Results of PCA of bill shapes for the lateral view. Grey lines represent bill shape for the principal component.

Figure 4. Results of the CVA of bill shapes for the dorsal view. Grey lines represent bill shape for the canonical variate.

Figure 5. Results of the CVA of bill shapes for the lateral view. Grey lines represent bill shape for the canonical variate.

Table 1. P-values from permutation tests in CVA. Analysis carried out on the dorsal view of the bill.

	GSW F	GSW M	WBW F	WBW M	SW F
GSW M	0.0308
WBW F	0.0001*	0.0001*
WBW M	0.0001*	0.0001*	0.0023*
SW F	0.0001*	0.0001*	0.1589	0.0002*
SW M	0.0001*	0.0001*	0.0276	0.0191	0.0556

Notes: GSW: Great Spotted Woodpecker; WBW: White-backed Woodpecker; SW: Syrian Woodpecker; F: female; M: male.

*Significant differences at P < 0.05 after Bonferroni correction (equivalent to P < 0.003).

Table 2. P-values from permutation tests in CVA. Analysis carried out on the lateral view of the bill.

	GSW F	GSW M	WBW F	WBW M	SW F
GSW M	0.6108
WBW F	0.0001*	0.0001*
WBW M	0.0001*	0.0001*	0.4408
SW F	0.0012*	0.0001*	0.8158	0.2879
SW M	0.0001*	0.0001*	0.6729	0.5621	0.5719

Notes: GSW: Great Spotted Woodpecker; WBW: White-backed Woodpecker; SW: Syrian Woodpecker; F: female; M: male.

*Significant differences at P < 0.05 after Bonferroni correction (equivalent to P < 0.003).

Table 3. Summary of analyses of traditional body trait differences in White-backed, Syrian and Great Spotted Woodpeckers. Means that do not share the same superscript letter are significantly different (P < 0.05).

(a) Bill length (mm)	mean ± se (n)
	Female	Male
White-backed	34.1^b ± 0.3 (15)	36.7^a ± 0.3 (14)
Syrian	27.9^de ± 0.6 (8)	29.9^c ± 0.2 (12)
Great Spotted	26.5^e ± 0.2 (38)	27.5^d ± 0.2 (40)
Significance of effects: species: F2,121 = 434.91, P < 0.001, sex: F1,121 = 48.26 P < 0.001, species × sex interaction: F2,121 = 4.79 P = 0.010.
(b) Body mass (g)	Mean ± se (n)
	Female	Male
White-backed	94.3^b ± 1.0 (15)	101.0^a ± 1.0 (14)
Syrian	77.0^cd ± 2.3 (8)	78.2^d ± 1.3 (12)
Great Spotted	80.8^cd ± 1.2 (37)	81.7^c ± 0.8 (40)
Significance of effects: species: F2,120 = 106.69, P < 0.001, sex: F1,120 = 6.28, P = 0.014, species × sex interaction: F2,120 = 2.92 P = 0.058.
(c) Wing length (mm)	Mean ± se (n)
	Female	Male
White-backed	141.8^b ± 0.7 (15)	144.3^a ± 0.4 (14)
Syrian	132.0^d ± 1.1 (8)	132.5^d ± 1.0 (12)
Great Spotted	139.2^c ± 0.5 (38)	137.8^c ± 0.6 (40)
Significance of effects: species: F2,121 = 66.82, P < 0.001, sex: F1,121 = 0.56, P = 0.456, species × sex interaction: F1,121 = 4.28, P = 0.016.
(d) Tail length (mm)	Mean ± se (n)
	Female	Male
White-backed	95.6^a ± 0.9 (15)	96.6^a ± 0.9 (14)
Syrian	89.5^b ± 1.0 (8)	88.4^b ± 0.7 (12)
Great Spotted	97.4^a ± 0.5 (38)	96.3^a ± 1.0 (40)
Significance of effects: species: F2,121 = 25.32, P < 0.001, sex: F1,121 = 0.18, P = 0.670, species × sex interaction: F2,121 = 0.60, P = 0.551.
(e) Tarsus length (mm)	Mean ± se (n)
	Female	Male
White-backed	23.9^b ± 0.3 (15)	25.2^a ± 0.4 (14)
Syrian	23.0^bc ± 0.8 (8)	22.8^c ± 0.3 (12)
Great Spotted	23.6^b ± 0.2 (38)	23.9^b ± 0.2 (40)
Significance of effects: species: F2,121 = 9.59, P < 0.001, sex: F1,121 = 2.90, P = 0.091, species × sex interaction: F2,121 = 2.54, P = 0.083.
(f) Body length (mm)	Mean ± se (n)
	Female	Male
White-backed	228.1^ab ± 1.3 (15)	231.8^a ± 1.6 (14)
Syrian	209.9^d ± 2.7 (8)	212.9^d ± 1.5 (12)
Great Spotted	225.5^b ± 0.9 (38)	221.9^c ± 1.0 (40)
Significance of effects: species: F2,121 = 54.20, P < 0.001, sex: F1,121 = 0.60, P = 0.439, species × sex interaction: F2,121 = 4.94, P = 0.009.