Tree Swallows (Tachycineta bicolor) are breeding earlier at Creamer’s FieldMigratory Waterfowl Refuge, Fairbanks, AK

We examined the average annual lay, hatch, and fledge dates of tree swallows(Tachycineta bicolor) breeding in Creamer’s Field Migratory Waterfowl Refuge inFairbanks, AK from 2000 through 2008. From 2000 to 2008, lay and hatch dateexhibited a significant negative relationship, indicating that the timing of swallowreproduction has advanced by approximately a week during this period.

unknown, The Alaska Bird Observatory in Fairbanks, AK