The American Ornithologists' Union awarded Dartmouth Professor Richard Holmes the 1993 William Brewster Award, which goes to the author of the best work on birds of the Western Hemisphere published during the last 10 years.
Holmes, a native Californian with a Ph.D. in zoology from the University of California at Berkeley, has been with the College for 25 years.
At Dartmouth Holmes has done extensive research on how animals, especially birds, respond to their environments, and his latest research focuses on the reduction of bird population in this area.
The research attempts to explain the recent, sudden and precipitous decline in 25 species of songbird populations in this area, he said.
Holmes is investigating birds both during breeding season in the White Mountains and winter season in the Caribbean in order to learn where the trouble lies.
He said his work aims to discover what factors regulate bird populations. Possible explanations include the number of young birds born per year and the increase in the mortality rate during winter.
Thus far, he said his research has found that "both are important."
Other factors affect the declining bird population as well, including changes in the environment due to land use he said.
Deforestation in the southern wintering areas could also have an effect, he said. But at present, there is no evidence supporting this theory.
In addition, instances of brood parasitism have grown to extremely high levels in environments near human habitats.
Brood parasitism occurs when one bird, such as the cowbird, leaves its egg in the nest of another bird, such as a songbird, to be "adopted."
Holmes said his research is the "only study trying to link breeding to wintering areas" in migrating birds of the temperate zone.
Holmes is also conducting extensive demographic studies of two particular bird species.
Holmes described one particular finding as the most significant he has made thus far. The "fact that events in breeding season are primary factors that effect these populations," he said. "Recruitment of birds this year is directly correlated with last year's reproduction success."
