Bird populations across North America have continually dropped in the past five decades, a decline defined as 29% since 1970. According to Science Magazine, all bird species other than native residents and waterfowl are sharply diminishing, maintaining the rough 29% decline for each, with some more drastic than others. One ornithologist, Ken Rosenberg, believes that this information is crucial. Since they are only estimates, he writes, the stakes could be much higher than anticipated. As a solution, Rosenberg states that “billions of dollars were invested into wetlands and wildlife refuges.” With the available funding and the warning from Rachel Carson’s Silent Spring, the activist community will attempt to continually increase conservation through other means; some suggest taxing hikers or bird-watching equipment to raise money for bird conservation organizations.