What predatory behavior involving vertebrates demonstrates walrus dietary flexibility?

Preying upon seals and sea birds such as eiders

Although the primary diet focuses on sessile invertebrates, evidence shows that walruses possess significant dietary flexibility, especially when circumstances dictate or opportunities arise. This flexibility extends to consuming vertebrates, which are high-protein, high-fat resources. Documented instances show walruses capable of preying upon sea birds, specifically mentioning eiders, which they might catch near colonies or the water surface. More remarkably, some individuals have been observed successfully preying upon seals. While this predatory behavior may not be frequent, it illustrates the biological capacity to supplement or substitute the standard benthic diet when necessary, a behavior also observed with various fish species in captive environments.