Ringing & Migration (2007) 23, 141-146 Biometrics of the Southern Grey Shrike Lanius meridionalis in relation to age and sex FRANCISCO GUTIÉRREZ-CORCHERO1, FRANCISCO CAMPOS2, M. ÁNGELES HERNÁNDEZ1* and ANA AMEZCUA1 1Department of Zoology & Ecology, Faculty of Sciences, University of Navarre, E-31080 Pamplona, Spain 2European University Miguel de Cervantes, c/ Padre Julio Chevalier 2, E-47012 Valladolid, Spain The biometrics of Southern Grey Shrike Lanius meridionalis and differences from the closely related Great Grey Shrike L. excubitor are poorly characterised. The aim of this study was to describe sex and age vari- ation in external biometric measurements for the nominate Southern Grey Shrike L. m. meridionalis in a population from northern Spain. In total, 174 Southern Grey Shrikes were ringed, measured, and sexed by molecular techniques. The overall biometry of the shrikes was summarised by Principal Components Analysis (PCA). There were significant differences in size between sex and age classes. We observed a sexual dimorphism in size, with adult males the largest and yearling females the smallest. According to the PCA, only the first principal component showed significant sex and age differences, and these were related to the tail, wing, third primary, white on primaries and white on rectrices. According to these data, and at least in terms of biometry, the Southern Grey Shrike is more similar to the Loggerhead Shrike L. ludovicianus than to the Great Grey Shrike. The Southern Grey Shrike Lanius meridionalis is a socially (Infante & Peris 2004). The goal of this study was to provide monogamous passerine without obvious sexual dimorphism a detailed description of the biometrics of the nominate in plumage. Ten subspecies have been described, with a Southern Grey Shrike in relation to sex and age of live largely Afro–Asian distribution, and the nominate L. m. animals, and to compare the results with other populations meridionalis is mostly found in the Iberian Peninsula and and closely related species. southeastern France (Lefranc & Worfolk 1997, Harris & Franklin 2000). In the Iberian Peninsula it is sedentary (Hernández 1999). According to Isenmann & Bouchet METHODS (1993), the Southern Grey Shrike is a different species from the Great Grey Shrike, and this has been accepted Study site and capture methods by taxonomic authorities (British Ornithologists’ Union We captured 174 shrikes during January–December 1997). Both species are part of a superspecies Lanius (1999–2002) in the province of Navarre (northern Spain). [excubitor] that includes the Chinese Great Grey Shrike L. Birds were captured using a variation of the Potter trap sphenocercus and the Loggerhead Shrike L. ludovicianus in (Craig 1997), ringed, measured and sexed. North America (Panov 1995, Schön 1998). The taxonomic separation between the Southern Grey Shrike and Great Biometrics and age determination Grey Shrike is based on morphological, ecological and The following body measurements were taken according to behavioural differences (Isenmann & Bouchet 1993, Panov Svensson (1992): the length of the wing (maximum chord), 1995, Schön 1998). More recently, genetic differences have third primary (3P) and tail feathers were measured with a also been described (Hernández et al 2004). 0.5 mm precision ruler; the length of the tarsus, middle Nonetheless, little is known about the biometrics of the toe and bill height, width and length (from the tip to Southern Grey Shrike. The only information available the distal edge of nostrils) were measured with a 0.1 mm is based on measurements of a few museum specimens precision calliper. We also measured the extent of white (Cramp & Perrins 1993) and, more recently, on a study on the primaries (WP, from distal edge of basal white area of live animals from the central-west Iberian Peninsula to wrist) and on the rectrices (WR, greatest length of white spot on inner web of the distal end of outer rectrix) (Fig 1) * Correspondence author with a 0.5 mm precision ruler as described by Collister & Email: [email protected] Wicklum (1996). In each shrike, both WP and WR were © 2007 British Trust for Ornithology 142 F. Gutiérrez-Corchero et al measured three times and the final value used for analysis The birds were classified as yearlings or adults. The was the average of these three measurements. Finally, yearlings (Euring age codes 3 or 5) had undergone a partial birds were weighed using a 0.1 g precision balance. Not moult in summer and winter (Svensson 1992) resulting in all measurements were taken on all birds and, therefore, a significant colour contrast in the wing feathers: newly the sample size varied. Weight was not considered in the moulted, shiny-black greater, median and lesser coverts analysis since it can vary substantially during the breeding contrasting with unmoulted black-brownish primaries, period (Collister & Wicklum 1996, Takagi 1996), but the secondaries and primary coverts (retained juvenile average value is reported. feathers). The adults were two or more years old (Euring Figure 1. Pattern of wings and tail in the Southern Grey Shrike, Figure 2. Mean scores for the three Principal Component axes by showing the white wing patch at the base of the primaries and the sex and age of Southern Grey Shrikes in northern Spain. Error bars: white at the end of the outer rectrices. ± standard error. © 2007 British Trust for Ornithology, Ringing & Migration, 23, 141-146 Biometrics of Southern Grey Shrike 143 Table 1. Average values (± standard deviation [sd]) of the variables measured in the Southern Grey Shrike in northern Spain according to sex and age with, in brackets, the sample size and range of values. Measurements are in mm, weight in g. WP: white on primaries. WR: white on rectrices. 3P: third primary. Males Females adults yearlings adults yearlings All birds Wing 106.30 ± 1.53 103.45 ± 1.35 105.64 ± 1.63 102.65 ± 1.74 104.61 ± 2.22 (51; 104–111) (30; 100–106) (44; 102–109) (49; 99–106) (174; 99–111) WP 55.16 ± 1.73 54.35 ± 1.47 54.91 ± 1.12 53.08 ± 1.64 54.65 ± 1.92 (48; 52.2–59.5) (28; 51.5–57.5) (43; 53.0–58.0) (48; 49.5–56.5) (167; 49.5–59.5) 3P 80.38 ± 1.54 77.89 ± 1.85 79.50 ± 1.56 77.60 ± 1.25 78.95 ± 1.92 (49; 77.5–84.0) (29; 74.0–82.0) (43; 75.5–82.0) (47; 75.0–80.0) (168; 74.0–84.0) Tail 116.78 ± 2.80 112.60 ± 2.63 114.02 ± 2.23 110.30 ± 3.34 113.50 ± 3.74 (48; 112.0–125.0) (29; 107.0–117.0) (43; 108.0–118.0) (48; 101.0–118.0) (168; 101.0–125.0) WR 49.33 ± 5.21 47.62 ± 5.00 45.40 ± 3.50 45.38 ± 4.29 46.91 ± 4.81 (48; 34.0–58.0) (28; 37.5–55.5) (43; 39.5–53.5) (46; 29.2–53.5) (165; 29.2–58.0) Bill length 14.13 ± 0.64 14.07 ± 0.59 13.90 ± 0.63 13.78 ± 0.63 13.96 ± 0.64 (51; 12.65–15.53) (30; 13.05–15.04) (44; 12.49–15.30) (49; 12.55–15.13) (174; 12.49–15.53) Bill depth 8.94 ± 0.19 8.86 ± 0.21 8.88 ± 0.20 8.83 ± 0.21 8.88 ± 0.20 (51; 8.39–9.30) (30; 8.46–9.25) (43; 8.44–9.30) (49; 8.37–9.45) (173; 8.37–9.45) Bill width 6.82 ± 0.23 6.83 ± 0.28 6.92 ± 0.31 6.80 ± 0.28 6.84 ± 0.27 (51; 6.37–7.22) (30; 6.30–7.50) (43; 6.40–7.56) (49; 6.00–7.35) (173; 6.00–7.56) Tarsus 29.92 ± 0.57 29.71 ± 0.69 29.88 ± 0.65 29.78 ± 0.59 29.83 ± 0.62 (51; 28.72–31.43) (30; 28.16–30.90) (44; 28.23–31.49) (49; 28.30–31.24) (174; 28.23–31.49) Middle toe 20.46 ± 0.65 20.40 ± 0.63 20.70 ± 0.56 20.51 ± 0.62 20.52 ± 0.62 (49; 18.09–21.95) (29; 19.14–21.75) (42; 19.71–21.75) (48; 18.50–21.48) (168; 18.09–21.95) Weight 62.26 ± 2.84 61.56 ± 2.92 63.98 ± 2.61 63.17 ± 2.57 62.80 ± 2.84 (51; 55.5–69.5) (30; 56.5–68.5) (40; 58.5–69.0) (47; 57.0–69.5) (168; 55.5–69.5) age codes 4 or 6) and lacked colour contrast on the wing (2002). DNA sequences corresponding to the Chromo- feathers as a result of a complete moult in summer after Helicase-DNA-Binding (CHD) protein (present in Z and breeding (Svensson 1992). These criteria were validated W sex chromosomes) were amplified using the Polymerase by comparing birds of known age that had been ringed Chain Reaction (PCR). PCR fragments were separated by as nestlings. gel electrophoresis on a 2.5% agarose gel, viewed under UV light and photographed (Gutiérrez-Corchero et al Sex determination 2002). According to Griffiths et al (1998), blood samples Blood samples (0.1 ml) were obtained by brachial with one DNA band (corresponding to the CHD-Z gene) venipuncture and placed on FTA® Classic Cards until indicate males, and samples with two bands (corresponding DNA extraction, according to Gutiérrez-Corchero et al to CHD-Z and CHD-W genes) are females. © 2007 British Trust for Ornithology, Ringing & Migration, 23, 141-146 144 F. Gutiérrez-Corchero et al Table 2.