Abstract: Elevation represents an important selection agent on self-maintenance
traits and correlated life histories in birds, but no study has analysed
whether life-history variation along this environmental cline is
consistent among and within species. In a sympatric community of
passerines, we analysed how the average adult survival of 25
open-habitat species varied with their elevational distribution and how
adult survival varied with elevation at the intra-specific level. For
such purpose, we estimated intra-specific variation in adult survival in
two mountainous species, the Water pipit (Anthus spinoletta) and the Northern wheatear (Oenanthe oenanthe)
in NW Spain, by means of capture–recapture analyses. At the
inter-specific level, high-elevation species showed higher survival
values than low elevation ones, likely because a greater allocation to
self-maintenance permits species to persist in alpine environments.
Photo : larsfoto.es
the intra-specific level, the magnitude of survival variation was lower
by far. Nevertheless, Water pipit survival slightly decreased at high
elevations, while the proportion of transient birds increased. In
contrast, no such relationships were found in the Northern wheatear.
Intra-specific analyses suggest that living at high elevation may be
costly, such as for the Water pipit in our case study. Therefore, it
seems that a species can persist with viable populations in uplands,
where extrinsic mortality is high, by increasing the investment in
self-maintenance and prospecting behaviours.