Professor Bartemeus says the study shows how human activities in the natural environment can change the travels of other organisms. The scientists say their findings may help the study of invasive species.
Brown pelican
BOB DOUGHTY: In another study, some brown pelicans on the west coast of the United States have been acting mysteriously. About twenty thousand brown pelicans fly south from the American state of Oregon each winter. Experts say the birds usually have flown to southern California or Mexico by this time of year. But, during the past three years, some have failed to fly south. Uncounted numbers of pelicans have remained in Oregon.
Many are thought to have died of cold or hunger or in severe storms. Wildlife rescuers in Oregon say some of the birds have been seen around restaurants and cafes. Even when people are present, the birds reportedly eat food that has been thrown away. And, people have been seen feeding them.
Experts say pelicans usually fear human beings. They urge people to leave the birds alone.
(MUSIC)
FAITH LAPIDUS: Large cities are known to have higher temperatures than rural areas in summer months. This extra heat can raise temperatures in cities by about one to three degrees Celsius compared to rural areas.
Scientists say there are many reasons for this. One reason is that heat from the sun can go through many of the building materials commonly found in cities. One such material is asphalt, a substance often placed on top of buildings and used to cover road surfaces.
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2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25