A Continent of Birds
Shaped by Geography
The unique “triangular” geography of North America shapes the birdlife in our three nations. The vast expanses of northern Canada and Alaska support relatively few breeding landbird species added up over such a large area; however, their total numbers are enormous. In contrast, a tremendous diversity of bird species, many with very small global populations, thrives in the narrow region of southern Mexico, where temperate and tropical systems meet. These disparate regions of great abundance and diversity are joined through the annual migrations of billions of birds, funneling southward across the continent each fall and expanding back into the northern latitudes each spring. Preserving this spectacle of birdlife requires a tri-national vision for conservation action.
|Landbird species richness is strongly associated with latitude.
Over the course of the year, more than 350 landbird species may be
found in southern Mexico, whereas a similar-sized area in the high
host fewer than 45 landbird species.
The total number of North American landbirds is staggering. PIF estimates that more than 10 billion birds are present at the end of each breeding season, with numbers receding as many die during migration and winter. This great abundance of birds is critical to the ongoing provision of fundamental ecosystem services, such as pollination, seed dispersal, and pest control, that support productive and resilient habitats throughout the continent.
Billions of birds—and almost 40% of all landbird species—traverse the continenttwice a year in spectacular migrations. Many of these birds move from breeding grounds in the vast boreal “nursery” to wintering grounds in the tropics, followingseasonal peaks of food availability. This migration, which links habitats throughout the hemisphere, has persisted for millennia and is one of the most complex and dynamic natural phenomena on the planet.
North American landbirds of our three nations are incredibly diverse, representing58 taxonomic families and 75% of the global landbird orders. Sparrows (78 species), flycatchers (76 species), wood warblers (64 species) and hummingbirds (57 species) are especially well represented
|Images: Yellow-rumped Warbler by James Livaudais, Snow Buntings by Eduardo E. Iñigo-Elias, Swainson's Hawk by Gerry Dewaghe, raptors by Kenneth V. Rosenberg, Blue-crowned Motmot by Greg Lavaty, Dot-winged Antwren by Gerry Dewaghe, Violaceous Trogon by Greg Lavaty.|