Dinosaur footprint casts from a Mesaverde (Campanian) coal mine near Gunnison, Colorado resemble those of the notorious "mystery dinosaur, Xosaurus" which was probably a giant hadrosaur. Existing footprint descriptions, although obscure and hard to verify, are too important to overlook, particularit

In July, cessation of territorial activity was accompanied by a regular upward drift of dawn weight, suggesting that weight had been regulated previously as a balance between expenditure and intake, perhaps without involving set-points.

It is concluded that either temporal differences or size differences of copepodids and adults would allow coexistence and that extreme size differences are probably unimportant compared to morphological differences of feeding appendages and perhaps behavioral differences.

Multiple environmental factors may act synergistically to influence demographic characteristics, and ultimately the dynamics, of biological populations. Using prospective and retrospective analyses of demographic data from a 40-year study of individually marked animals, we investigated the demograph

Background Viruses impact nearly all organisms on Earth, including microbial communities and their associated biogeochemical processes. In soils, highly diverse viral communities have been identified, with a global distribu‑ tion seemingly driven by multiple biotic and abiotic factors, especially so

SummaryAlthough secondary metabolites are prevalent in floral nectar, the ecological consequences for pollinators and pollination remain relatively unexplored. While often deterrent to pollinators at high concentrations, secondary metabolite concentrations in nectar tend to be much lower than second

A core of varved lake sediments from Devlins Park, Front Range, Colorado, has yielded a radiocarbon-dated pollen record of environments during the last major advance of Pinedale ice. The downstream end of Devlins Park was dammed by Pinedale ice from 22,400 to 12,180 BP, creating the lake. The pollen

“Pollination syndromes” are specific combinations of floral traits that are proposed to evolve convergently across angiosperm lineages in response to different types of animal pollinators. In spite of their long history, pollination syndromes have not been tested adequately–they rarely have been exa

It is suggested that during the summer when marmots are not hibernating and are actively feeding, brain insulin levels may play a role in regulating food intake.

Two different mechanisms can result in multiple paternity within fruits: deposition of a mixed pollen load due to carryover of pollen from flower to flower and multiple pollinator visits in close succession. I investigated the extent of multiple paternity within fruits of Ipompsis aggregata containi

Differences in foraging behavior observed on two plant species with similar floral and inflorescence structures increase the neighborhood size for nectar producing species and make it increasingly unlikely that random drift will be a dominant mode of evolution in populations of these species.

AbstractRelatively little is known about the effects of specific parasites on sexually selected behavioral traits. We subjected free‐living mountain white‐crowned sparrows (Zonotrichia leucophrys oriantha) to a playback experiment to identify the effect of hemosporidian parasites on potentially sexu

AbstractAlthough bedrock weathering strongly influences water quality and global carbon and nitrogen budgets, the weathering depths and rates within subsurface are not well understood nor predictable. Determination of both porewater chemistry and subsurface water flow are needed in order to develop

Summary1. Populations of a number of sub‐tropical stream insect species have been found to show unexpected patterns of genetic variation, with more differences between samples from the same stream than between whole streams or between subcatchments. Many samples also showed deviations from Hardy–Wei

In addition to encoding referential information and information about the sender's motivation, mammalian alarm calls may encode information about other attributes of the sender, providing the potential for recognition among kin, mates, and neighbors. Here, we examined 96 speckled ground squirrels (S

The microdistribution of adult subalpine butterflies was examined in relation to several components of the mountain meadow flora in Gunnison County, Colorado. With the exception of two small, sedentary species, there was no significant correlation between the microdistribution of the butterflies and

AbstractWarm temperatures are required for insect flight. Consequently, warming could benefit many high‐latitude and high‐altitude insects by increasing opportunities for foraging or oviposition. However, warming can also alter species interactions, including interactions with natural enemies, makin

Heterogeneous distributions of resources and organisms are characteristic of most ecosystems, but empirical understanding of the causes and consequences of heterogeneity is limited. We investigated whether predatory fish influenced the heterogeneity (spatial variability) of resources (algae) by modi

Evidence is presented in support of the suggestion that a hovering bird is able to move between flowers more quickly than one that is perching, however, this advantage to hovering may be offset by the higher energetic costs of hovering as compared with perching.

This study addresses the field-scale architecture and dimensions of fluvial deposits of the lower Williams Fork Formation through analysis of outcrops in Coal Canyon, Piceance Basin, Colorado. The lower Williams Fork Formation primarily consists of mud rock with numerous isolated, lenticular to chan