Tivoli, New York

Late spring brings the final wave of migrant songbirds to establish breeding territories in the newly leafed canopy. These late arrivals depend on the insect abundance that comes with full leaf development, timing their nesting season to match this peak food supply.

A Red-eyed Vireo appeared at Great Vly WMA on May 6th, marking one of the season's last major migrant arrivals. This timing aligns with peak insect activity as moths like the Oak Besma and Red-fringed Emerald emerge to feed on fresh oak leaves. Year-round residents like Tufted Titmouse and White-breasted Nuthatch now share the canopy with returning migrants including Gray Catbird, which has begun its distinctive calling from dense understory. American Robin pairs are already deep into nesting, while Chimney Swift has returned to hunt insects above the treetops. Below the canopy, Wood Duck recently appeared along wetland edges where the breeding season creates new territorial pressures across all levels of the forest.

Research confirms that Red-eyed Vireos time their arrival precisely to match peak caterpillar abundance, with caterpillars making up 50% of their summer diet. The first males reach breeding areas by early May, but most arrive during the second and third weeks to coincide with full leaf emergence and maximum insect activity.