Keith A. Hobson Jeff Kelly Peter P. Marra Leonard I Wassenaar Craig A. Stricker Richard R. Doucett Michael B. Wunder 2009 <p>In a recent paper published in <i>The Auk</i>, Smith et al. (2009) raised serious concerns over an apparent lack of reproducibility in their study of stable hydrogen isotope values (&delta;D_f ) in raptor feathers. The authors based their concerns on results obtained from different laboratories to which they submitted original and blind &ldquo;repeats&rdquo; over a multiyear period. A regression of the original sample &delta;D versus &ldquo;repeat&rdquo; measurements showed an increase in the magnitude of residuals with increasing &delta;D_f , especially for values greater than about &minus;80&permil; (Smith et al. 2009: fig. 2). Because of this, the authors &ldquo;caution against the continued use of &delta;D_f for predicting geographic origin, and for addressing important conservation questions&rdquo; (p. 41) and conclude that &ldquo;it is counterproductive to move forward [with hydrogen isotopes in avian studies] without first establishing full confidence in the technique that underlies&nbsp;such insights and conservation recommendations&rdquo; (p. 45). We disagree with these sentiments.</p> application/pdf 10.1525/auk.2009.126.4.2 en American Ornithological Society Does a lack of design and repeatability compromise scientific criticism? A Response to Smith et al. (2009) article