Data on the travel routes of migrating birds today largely come from extremely lightweight radios,
geolocators, and satellite tags, which can be safely attached to individual birds.The use of geolocator
backpacks has revealed that migrant wood thrushes and purple martins take much longer to travel from
Pennsylvania to the Amazon basin in the fall than they do when going in the opposite direction in the spring
(Stutchbury et al. 2009). For example, one martin completed its spring migration in about 2 weeks, which
required an average trip of 600 kilometers each day. Why the difference in speed of travel between the
fall and spring migrations?
Sample Solution