In general, older birds not only showed up at the wildlife refuge in Alabama earlier than younger birds, they also tended to stop for shorter durations than younger birds. On average, the older birds clearly had an advantage…more fat stores. By their estimations, using flight simulation software, the older birds with larger fat stores were potentially capable of flying on average 2,260 kilometers without needing to stop for fuel (16km minimum and 4,960km maximum).
Zenzal TJ, Moore FR. Stopover biology of ruby-throated hummingbirds (Archilochus colubris) during autumn migration. The Auk 133(2):237-250, 2016. doi: http://dx.doi.org/10.1642/AUK-15-160.1
Categories: Comparative Physiology