Howling by coyotes (Canis latrans): variation among social classes, seasons, and pack sizes

From January 1991 to June 1993 we observed 54 coyotes (Canis latrans) for 2 507 h in Yellowstone National Park, Wyoming, during which we observed 517 h owling events. Among coyotes of different types of social organization (res ident versus transient), members of resident packs initiated or participate d in howling events, while transient individuals were never observed howlin g (n = 51 h of observation). For members of resident packs, alpha coyotes s pent more time howling and had a higher rate of howling events than beta co yotes and pups; beta coyotes and pups howled similarly. The percentage of t ime and the rate of howling events typically peaked in the dispersal and br eeding seasons, with the lowest rate of howling during pup rearing. Social rank and season did not influence the length of howling events. Pack size d id not affect howling rates among individuals in a pack or the alpha pair. With respect to space-use patterns, coyotes in resident packs howled more f requently than expected along the periphery of the territory than in the co re area. We concluded that, like wolves (Canis lupus), all coyotes in the r esident pack did not contribute equally to howling duties; alpha coyotes ho wled more than all coyotes. Howling by coyotes appears to serve a territori al spacing function that is mainly performed by the alpha pair of the resid ent pack.