Not just the Black-throated Green Warbler is fledging right now. Most of the species that nest on the island have baby birds about, with the exception of Leach’s Storm-Petrels, who’s eggs will begin to hatch in about a week. Yellow Warblers fledge after about 11 days in the nest. At this point, they are both large and feathered enough to regulate their own body temperature, and too large to all fit in the nest together. Fledging is a strategy birds employ to reduce the risk of continuing to put all their eggs in one basket, so to speak. Spreading out the fledglings ensures that a predator that takes one of the fledglings will not eat them all and minimizes the risk of disease affecting the entire clutch. Here is a Yellow Warbler fledgling and a pair of Winter Wrens, one fledgling, one adult. Click to enlarge.