There is grow ing concern that populations o f m igratory ungulates are declining globally. Causes o f declines in m igratory behavior can be direct (i.e., differential harvest o f migrants) or indirect (i.e., habitat fragmentation orland-use changes). Elk fCervus elaphusj are an im portant big game species in North America whose migratory behavior is changing in some montane ecosystems. We evaluated evidence and hypotheses for changes in m igratory behavior and population decline in one o f Canada’s largest elk populations, the Ya Ha Tinda. We com pared the ratio o f m igrant to resident elk (M:R) in the population and seasonal spatial distributions obtained from 22 w inter and 13 sum m er helicopter surveys between 1972 and 2005. Timing o f m igration and the sum m er distribution for a sample o f radiocollared elk also was com pared for 1977-1980 (early period) and 2001-2004 (recent). The population M:R ratio decreased from 12.4 (SD = 3.22) in the early period to 3.0 (SD = 1.63). The decrease was greater than expected based on population change. Declines in M :R also m irrored behavior o f radiocollared elk. M ore than 49% o f radiocollared elk we m onitored resided near the w inter range year-round b y 2001-2004, and migrants were spending less time on sum mer ranges. We found w inter range enhancements, access to hay fed to wintering horses, recolonization b y gray wolves fCanis lupusj, and management relocations o f elk were m ost consistent with observed elk population grow th (adjusted for harvest and removals) and the change in migratory behavior. However, we could not isolate the effects o f specific factors in time-series population modeling. We believe directly relating migrant and resident demography to habitat and m ortality factors will be required to understand the mechanisms affecting m igratory behavior in this and other montane elk herds

Alberta, Canada, Canis lupus, Cervus elaphus, elk, habitat enhancement, habituation, migrantresldent ratio, migration, prescribed fire, winter range, wolf