The American Robin is the largest, most abundant and broadly distributed thrush in North America. The presence of this songster in the backyard setting, together with its loud, musical voice, make it one of the most recognizable birds in North America. Indeed, the American Robin has been described as "America's favorite songbird" ( Sharp 1990 ), and its annual arrival in northern latitudes is widely viewed as a harbinger of spring. Most people know it as a breeding bird of suburban and farmland areas, where it nests in shade trees and forages in moist grasses, often tugging at worms on lawns. Because the American Robin often lives in close proximity to humans, it has great potential to reconnect Americans to the natural world through backyard learning ( Young 2012 ).
Ecologically speaking, the American Robin is impressive. Few species share its broad North American range, and ability to live in both anthropogenic and natural habitats. Its diet is highly variable across the annual cycle, changing from primarily soft-bodied invertebrates, especially earthworms, in spring and summer, to primarily fruit in autumn and winter. During the nonbreeding season, flocks of hundreds or thousands migrate to lower elevations and latitudes, where they form large communal roosts from which they track fruit resources. Despite being a classic sign of spring at northern latitudes, not all American Robin populations are migratory, and some spend the winter months close to their breeding grounds.
With some exceptions, American Robin breeding populations are stable or increasing across North America. Common in suburban parks and gardens, it appears to have benefited from urbanization and agricultural development. Early studies of American Robin nesting habits during the 1930s and 1940s still provide important data ( Howell 1942 , Young 1955 ). Other well-studied aspects of robin biology are its diet and the ontogeny of foraging behavior ( Wheelwright 1986 , Vanderhoff and Eason 2007 , Vanderhoff and Eatson 2008 ), fruit choice ( Jung 1992 , Willson 1994 , Lepczyk et al. 2000 ), mechanisms of fruit selection ( Sallabanks 1993a ), seed dispersal ( Renne et al. 2002 , Bartuszevige and Gorchov 2006 , Zika 2010 ), vocalizations ( Johnson 2006 , Vanderhoff and Eason 2009b , Dowling et al. 2012 , Seger-Fullam et al. 2011 ), geographic variation in size, shape, and plumage ( Aldrich and James 1991 ), reproductive behavior ( Rowe and Weatherhead 2007 , Rowe and Weatherhead 2011 ) and its role in the transmission of West Nile virus ( Molaei et al. 2006a , Savage et al. 2007 , Molaei et al. 2008 , Hamer et al. 2009 , Kent et al. 2009 ).
Despite being one of the most ubiquitous species in North America and serving as a model species in many studies, there is still much to be learned about the ecology of the American Robin. Of particular interest are studies of regional differences in reproduction, territoriality, communication, and migration, as well as the effects of humans on American Robin populations (e.g., landscape alteration, light and noise pollution, and climate change).