Living in seasonal environments has its challenges. Temperate breeding birds migrate to southern regions during fall to avoid winter conditions. Birds return to breeding grounds following spring to take advantage of local resources to feed their offspring. Although annual migration has benefits, it also has associated costs. High metabolic activities may result in by-products that cause oxidative damage to DNA, and consequently shorten telomeres, the protective structures at the end of chromosomes. Therefore, telomere attrition could be influenced by the distance traveled during annual migration. In this study we aim to (1) test the hypothesis that telomere loss is related to migratory distance between non-breeding and breeding grounds, and (2) examine relationships among oxidative damage, migratory distance, and telomere loss. Telomere loss will be assessed as the difference between telomere length of captured red-winged blackbirds (Agelaius phoeniceus) in 2018 and after recapture in 2019. Oxidative damage will be measured as malondialdehyde (MDA) concentration in blood plasma. To determine migratory distance, we used hydrogen stable isotopes from distal claw samples, which estimate the bird’s overwinter latitude. We predict (1) higher telomere loss in long-distance migrants compared to shorter-distance migrants, (2) females, who travel farther, will have higher telomere loss than males, and (3) oxidative damage will be positively correlated with migratory distance and telomere loss. These data will increase understanding of trade-offs between traveling farther to more favorable overwinter conditions and the associated costs.