In a new study published in The Auk, scientists report that well-fueled older tiny Ruby-throated Hummingbirds (Archilochus colubris) might be capable of non-stop flights of over 4,000 kilometers, wind conditions permitting. They made this remarkable observation while studying birds from 2010-2014 as the animals made stopovers at a wildlife refuge during their annual migration to South America.
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