Distribution of longevity in Kirtland’s Warbler ( Setophaga kirtlandii ) including a new record for the family Parulidae

Understanding the longevity of Kirtland’s Warbler (Setophaga kirtlandii) is important for population models, research logistics, and adaptive management to sustain its recovery from endangered status. Kirtland’s Warblers were captured in mist nets and uniquely banded in Michigan (USA) and Wisconsin (USA) 1984–2001 and resighted (observed or recaptured) in Michigan, Wisconsin, and Eleuthera (The Bahamas) until 2005. An analysis of 984 individuals banded as hatch-year birds and 770 banded as after-hatch-year birds showed that the oldest minimum age at last encounter was 12 years, setting a new longevity record for the family Parulidae. Two females and five males were ≥10 years old at last encounter. The distribution of minimum age at last encounter followed the expected trend based on annual mortality estimates for the species. The minimum age at last encounter was 1.4 ± 0.04 years (mean ± SE) for all individuals (including birds whose last encounter was in their hatch year) and 2.3 ± 0.05 years for those who survived to at least their second year. Older individuals of both sexes moved 14.8 ± 4.78 km (range: 0.8–35 km) from older stands to younger stands. Based on a plumage scale intended to predict age of males, the high-scoring darker features of the two oldest females suggest females become more male-looking with age. We recommend accounting for our new longevity record in population models and taking caution when selecting unique color band combinations for individual warbler identification in projects within about 15 years of other banding efforts.