Rapid changes in climate have drastically altered the phenology of plants and insects worldwide. Whether migratory birds can adapt to these changes remains a paramount concern, especially in light of declining populations. In North America, aerial insectivores have experienced persistent and widespread declines over the past several decades. This guild of birds is highly diverse in their ecology and behaviour, but are united by their common diet. Changes to insect emergence dates could thus be especially challenging to aerial insectivores if they are unable to quickly adapt their migratory schedules. Here, we examine changes in migratory timing over the past decade in the Vaux’s swift (Chaetura vauxi), a small western North American migrant with a unique migratory behaviour wherein hundreds to thousands of individuals roost communally throughout migration. Data collected by citizen scientists over the past decade provides an almost unprecedented opportunity to examine migratory timing in an estimated 80% of the entire population of Vaux’s swifts. Our analysis demonstrates a rapid advancement of spring migration across much of the species’ flyway. This change in migratory phenology may indicate that Vaux’s swifts are able to acclimate or adapt to changing environmental conditions, which may in part explain why this species, amongst the aerial insectivores, is experiencing a less drastic population decline.