Life-history Traits and Divergence in Population Trends of two North Pacific Auks: Rhinoceros Auklet <i>Cerorhinca monocerata</i> and Tufted Puffin <i>Fratercula cirrhata</i>

Population trends in two closely related and ecologically similar North Pacific auks, the Rhinoceros Auklet Cerorhinca monocerata and Tufted Puffin Fratercula cirrhata, have diverged over recent decades: stable in the former, declining in the latter. I propose that differences between the two species in a broad suite of interrelated morphological, demographic, behavioral, and physiological life-history traits could explain their differing responses to recent environmental conditions.