Late May through early June marks the peak of harbor seal (Phoca vitulina) pupping season along Pacific Northwest coastlines, with newborn pups appearing on rocky shores, beaches, and floating logs throughout the region. Harbor seal mothers give birth to single pups (usually weighing 20-24 pounds) during low tide, allowing pups to dry and bond before the tide returns. The pups can swim within hours of birth but spend considerable time hauled out on rocks resting and nursing. Along the Washington and Oregon coasts, Puget Sound, and British Columbia's Salish Sea, watch for small groups of seals basking in the late spring sunshine, with adorable spotted pups staying close to their mothers. Harbor seals are the most common marine mammal in the Pacific Northwest, with populations recovering well since the Marine Mammal Protection Act of 1972.