A report on new research showing that Arizona Bald Eagles are expanding their ranges to include regions of the Northwestern United States. A description of how birds conform to Zipf's Law, a pattern of communication commonly observed in human language where a few words are used very frequently while many words are used rarely. Those words (sounds in the case of birds) are simplified to make the communication process faster and more efficient. A Western Resource Associates statement on the condition of the Colorado River. Bird of the episode: American Pipit. Birding Hotspot: Aubrey Peak Wilderness. Friend of wildlife: Arizona Chapter of the National Association of Environmental Professionals.