Not only do they face natural perils such as storms, predation, and drought, they now contend with ever increasing human caused threats. These threats include contamination from pesticides, herbicides, and industrial pollution. Birds are also losing their homes and migration stop-overs through timber harvesting, urbanization, grazing, and farming. Cowbirds parasitize these nests by laying their eggs in them. More than you might think.
Migratory birds are integral parts of our culture, heritage, and economy.
Their arrival and departure heralds the changing seasons, and their beauty adds to our quality of life. They play vital roles in our environment by controlling insect populations, spreading seeds, and pollinating flowers. Their sensitivity to declines in environmental quality makes them useful as an early warning system for human welfare. The great diversity of neotropical migratory birds found in Arizona attracts thousands of birdwatchers each year, pumping millions of dollars into the state's economy.