Bird species diversity can in part be traced to its land formation. For example after millions of years of earthquakes and volcanic eruptions, the previously separate American continents eventually became connected. The stretch of land between continents—now Central America— contains what might be expected of a bridge - representation of species from both continents. Bird species began migrating to the area many millions of years ago. Birds such as the jay came from the north, while hummingbird species appeared from the south.

In addition to its bridging geography fruits and flowers attract birds looking to diversify their diet and travel great distances or in some cases stay put because of localized abundance. Birds that feed mostly on nectar or fruit are increasingly rare at locations away from the equator. With trees fruiting all year in the tropics, even birds like the resplendent quetzal can survive on diets that are nearly exclusive to certain fruits.

Fruits and flowers provide birds with food, but many of these plants also rely on birds. In the neotropics, hundreds of bird species fill the important ecological role of dispersing fruits and pollinating flowers. The bird’s mobility makes them an ideal carrier. However, with high mobility, bird communities require large areas of land to survive. Thus, birds are strongly affected by human alterations and fragmentations of the forest. Because many plants, in turn, rely on birds to access adequate habitat, isolating forest fragments creates a feedback loop of species reduction. With accelerating loss of birds and plants, deforestation becomes a serious problem. The conservation of large land areas is very important to maintaining these species in the tropics.