Reintroduced bighorn sheep: do females adjust maternal care to compensate for late-born young?

Little is known regarding the potential adjustment of maternal care towards late-born young by reintroduced female ungulates, which may be adapted to environments quite different than those at their release site. We compared nursing behaviors of young to investigate whether females would adjust maternal care toward late-born young between two populations of reintroduced bighorn sheep (Ovis canadensis) in Utah, USA. Neonates on Mount Timpanogos were born on average 28 days later in 2002 and 13 days later in 2003 than neonates in Rock Canyon. Suckling and weaning behaviors, however, were similar in 2002 and 2003 between those populations, except for the number of unsuccessful suckles, which was greater for young in Rock Canyon than for young on Mount Timpanogos during the middle of lactation in 2002. Our results provide preliminary evidence that females did not adjust maternal care to compensate for late-born young within the first 3 years following reintroduction, which possibly influenced survivorship of young.