Biometrics amongst DippersCinclus cinclusin the north of Spain

Abstract

Biometric data were collected from Dippers Cinclus cinclus in Navarre (northern Spain) between 1992 and 1994. Male and female individuals of any age could be separated by using a discriminant function in the form y + 2x > 243 for male individuals, where y = weight in g and x = wing length in mm. All measurements (bill, wing, tarsus, weight) differed significantly between the sexes, but not between adults and first years within sexes. Average wing length in Navarre is the smallest so far published for Dippers in Europe. While broadly supporting Bergmann's rule about effect by latitude, local differences from other Spanish populations suggest that other features also influence body size in Dippers.

Biometric Differences Among the DipperCinclus cinclusPopulations of Spain

“…Our data confirm the findings by Esteban et al (2000) that the Spanish Dipper populations do not follow Bergmann's rule, which works in most species of non-migratory birds (Ashton 2002, Mieri & Dayan 2003. Species that are always present in the same area would be more affected by climatic factors than those that avoid winter cold by emigrating to other areas.…”

“…As in other studies on Dipper in Spain (Esteban et al 2000, Villarán et al 2001, there were no significant differences among juveniles and adults in metric traits. In some European countries wing length is a precise criterion to sex Dippers (Svensson 1992), but not in Spain (Campos et al 2005).…”

“…Birds were weighed with a precision scale (0.1 g). Since weight may change during the year (Ormerod et al 1986, Bryant & Tatner 1988, O'Halloran et al 1992, Esteban et al 2000 we only used data from June to October. Age was measured as in Svensson (1992).…”

“…Galbraith & Broadley 1980, Rockenbauch 1985, Schmid & Spitznagel 1985, Ormerod et al 1986, Marzolin 1990, O'Halloran et al 1992, Robert 1992, Tasinazzo et al 2000. However, only a few studies have been carried out in Spain with few samples in relatively small areas (Marsá 1988, Esteban et al 2000, Villarán et al 2001. As with other birds, biometric studies can be useful to better understand the distribution and biology of the Dipper and improve conservation efforts (Zink & Remsen 1986, Tellería & Carbonell 1999.…”

Usefulness of Biometrics to Analyse Some Ecological Features of Birds

“…This is evidenced in the White-throated dipper. Throughout Europe, its size (measured by wing and tarsus length) increases towards Northern latitudes (Esteban et al, 2000), which is in agreement with Bergmann's rule mentioned previously. However, within the Iberian Peninsula, the White-throated dippers from the South are significantly greater than those from the North (Campos et al, 2005c), which contradicts Bergmann's rule and has been explained by the influence of local environmental conditions (Arizaga et al, 2009).…”