Delphinium nelsonii Greene (Ranunculaceae) individuals which were watered produced significantly more nectar per flower than did control individuals. The watered plants also set significantly more seeds per flower than did the controls. Hand pollinations suggest that the seed set difference was due

The fact that residual nectar exists is consistent with predictions of optimal foraging theory but more detailed work is necessary before it can be concluded that the volumes left behind in A. columbianum flowers are optimal.

Evidence is presented that discrimination occurs because white flowers have inferior ‘nectar guides’ and therefore require longer handling times than blue flowers, and pollinators may experience lower net rates of energy intake on white flowers, a sufficient reason for undervisitation by optimally-f

The hypothesis that a sychrony of the time of seed dispersal and the period when most ants (mutualists) and least rodents (predators) are active would be advantageous to the plant species is discussed.

Females tended to specialize upon one or two species, at least in the short term, and the pattern of oligophagy for the population as a whole is partly generated by variation in the host-seeking behavior of individual females.

Relative tendencies toward dispersal or philopatry in a marked population of alpine mammals, the pika (Ochotona princeps), were investigated over a 3-year period in the Rocky Mountains of Colorado to help understand their low intrapopulation genetic variability.

In Senecio, flowering phenology patterns and differences among pollinators in foraging behavior may have more important consequences for seed set and gene flow patterns than plant density or plant size.

Results of this study suggest that the wing whistle of male broad-tailed hummingbirds is important in maintenance of courting territories and hence in reproductive success.

The observed differences in catchability between sexes is also correlated with the sexual differences in flight behavior reported here, and the time spent in flight, short life expectancies, and time budgets of Colias suggest that the time available for flight activity during an individual's lifetim

Weasels were determined to be more effective predators of pikas than martens, and these asymmetries in behavior and alarm vocalizations may indicate that responses reduce an individual's risk of predaton by weasels.

Numerous mountain watersheds in the Colorado Mineral Belt (CMB) are impacted by acid rock drainage (ARD) and acid mine drainage (AMD), which mobilize metals and rare earth elements (REEs) into surface waters. In the upper Roaring Fork watershed near Independence Pass, natural ARD from a highly miner