Boelman, Natalie T, Jesse S Krause, Shannan K Sweet, Helen E Chmura, Jonathan H Perez, Laura Gough, and John C Wingfield. “Extreme Spring Conditions In The Arctic Delay Spring Phenology Of Long-Distance Migratory Songbirds”. Oecologia 185, no. 1. Oecologia (2017): 69 - 80. doi:10.1007/s00442-017-3907-3.