{"fact":"While migrating, American crows were found to roost communally every night, often in large established roosts that have existed for decades.","context":"All crows roosted at communal roosts while migrating, and crow numbers 1, 4, and 8 all roosted in communal roosts within 8 km of each other in 2004, 2005, and 2009, respectively (Fig. 1; roost area 1). … Many large crow roosts have been in existence for decades (>40 years; Emlen 1938; Black 1941; Graber et al. 1987).","source":"Michael P. Ward; Arlo Raim, The fly-and-social foraging hypothesis for diurnal migration: why American crows migrate during the day, 10.1007/s00265-011-1151-0","index":119}