SHORT RESEARCH AND DISCUSSION ARTICLE Selection of tawny owl (Strix aluco) flight feather shaft for biomonitoring As, Cd and Pb pollution Rita García Seoane 1 & Zulema Varela Río 1,2 & Alejo Carballeira Ocaña 1 & José Ángel Fernández Escribano 1 & Jesús Ramón Aboal Viñas 1 Received: 20 September 2017 /Accepted: 4 February 2018 # Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract In this study, we determined the concentrations of As, Cd and Pb in the shaft of all primary flight feathers from ten tawny owl (Strix aluco) specimens, with the aim of selecting which shaft of the corresponding primary feather should be used in biomon- itoring surveys to enable inter-individual comparisons of the levels of these metals. The birds had died between 2006 and 2013 and their bodies were stored in the various Wildlife Recovery Centres in Galicia (NW Spain). The analyses revealed a high degree of inter-shaft variability, mainly in the concentrations of As and Cd. However, it was possible to identify the most representative samples in each case: for As, the shaft of primary flight feather number 5 (S5) (which represented 11% of the total As excreted in all of the primary flight feathers); for Cd, the shaft of primary flight feather number 2 (S2) (11% of the total excreted); and for Pb, the shaft of primary flight feather number 8 (S8) (14% of the total excreted). However, the difficulties associated with the analytical determination of these pollutants in the shaft should be taken into account when this technique is applied in biomon- itoring studies. Keywords Air pollution . Bioaccumulation . Biomonitoring . Feather . Raptor . Terrestrial food chain Introduction Birds have been used in many biomonitoring studies in the last few decades because of increasing evidence that their popula- tions are strongly affected by environmental pollution of anthro- pogenic origin, particularly as a result of exposure to heavy metals (Altmeyer et al. 1991; Dauwe et al. 2003; García- Seoane et al. 2017). Birds of prey (raptors) are commonly used as bioindicators of the levels of metals in the environment, for the following reasons: (i) they are extremely sensitive to varia- tions in the levels of these pollutants (Furness 1993; Castro et al. 2011), (ii) they occupy the highest trophic levels in terrestrial ecosystems (Martínez et al. 2012), (iii) they are highly territorial and can spatially integrate pollutant levels from across their extensive home ranges (Altmeyer et al. 1991) and (iv) many of the species used in biomonitoring studies are widely distrib- uted throughout the world (Cramp 1978; Varela et al. 2016). Different types of tissue have been extracted from raptors for biomonitoring purposes (e.g. liver and kidney); however, the methods used to obtain the samples are invasive, which may have negative effects on species abundance, population survival and on the corresponding habitats (Cardiel et al. 2011; Castro et al. 2011). Hence, feathers are now often used in a non-invasive approach to monitoring pollutant exposure in terrestrial and aquatic ecosystems. This method has been widely used to detect episodes of environmental pollution, as well as to evaluate spatio-temporal variations in the levels of some elements at both small and large scales (e.g. Dietz et al. 2006; Bustnes et al. 2013; García-Seoane et al. 2017). Different types of feathers have been analyzed in biomon- itoring surveys: contour and primary and secondary flight feathers (e.g. Dauwe et al. 2003; Varela et al. 2016); tail Responsible editor: Philippe Garrigues Electronic supplementary material The online version of this article (https://doi.org/10.1007/s11356-018-1477-5) contains supplementary material, which is available to authorized users. * Rita García Seoane rita.garcia.seoane@usc.es 1 Ecology Unit, Department Functional Biology, Universidade de Santiago de Compostela, Fac. Biología, Lope Gómez de Marzoa s/n, 15702 Santiago de Compostela, La Coruña, Spain 2 Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal Environmental Science and Pollution Research https://doi.org/10.1007/s11356-018-1477-5