Data from: A migratory northern ungulate in the pursuit of spring: jumping or surfing the green wave?

The Forage Maturation Hypothesis (FMH) states that herbivores migrate
along a phenological gradient of plant development in order to maximize
energy intake. Despite strong support for the FMH, the actual relationship
between plant phenology and ungulate movement has remained enigmatic. We
linked plant phenology (MODIS-NDVI) and space use of 167 migratory and 78
resident red deer (Cervus elaphus) using a space-time-time matrix of
"springness", defined as the instantaneous rate of green-up
(IRG). Consistent with the FMH, migrants experienced substantially greater
access to early plant phenology than residents. Deer were also more likely
to migrate in areas where migration led to greater gains in springness.
Rather than "surfing the green wave" during migration, migratory
red deer moved rapidly from the winter to the summer range, thereby
"jumping the green wave". However, migrants, and to a lesser
degree residents, did track phenological green-up through parts of the
growing season by making smaller-scale adjustments in habitat use. We
conclude that, whereas in some systems migration itself is a way to surf
the green wave, in others it may simply be a means to re-connect with
phenological spring at the summer range.