Life-History Consequences of Maternal Condition in Alaskan Moose

Abstract

We studied life-history characteristics of Alaskan moose (Alces alces gigas) including the effects of maternal condition of adult females (>33 months old) on survival and physical condition of young during their first year-of-life. We also examined the relation between maternal condition and reproductive parameters of individual adult moose, and tested for effects of those parameters on timing and synchrony of parturition. We radiotracked adult females captured in both March 1996 and 1997 throughout the year with intensive monitoring occurring during spring and early summer. That procedure enabled us to capture the offspring of females we monitored and record other variables related to reproductive success. Females with greater rump fat thickness had higher rates of pregnancy, gave birth to more twins, and produced young with higher birth masses than did females with less rump fat. Time-to-death for individual young increased as birth mass increased and decreased as birth date and litter size increased; those birth variables, however, did not act upon time-to-death independently. Our results indicated maternal condition influenced subsequent variables associated with birth, which ultimately affected filture survival of offspring. Further, timing of reproduction varied between the 2 years, with births occurring earlier but not more synchronously in 1996 than in 1997. Time of parturition occurred earlier for individual females with the thickest rump fat. That outcome indicated that timing of parturition was the result of environmental factors acting on females prior to giving birth rather than effects of attempting to avoid predation.

Reproductive seasonality in African ungulates in relation to rainfall

“…Our findings contrast with those of research conducted in northern temperate regions on Dall sheep (Ovisdalli, Rachlow and Bowyer 1991), moose (Alces alces, Bowyer et al 1998;Garel et al 2009), roe deer (Capreolus capreolus, Linnell and Andersen 1998) and reindeer (Rangifer tarandus, Post et al 2003), suggesting that synchronisation of the mother and newborn requirements with high nutritional conditions after parturition (Dauphiné and McClure 1974;Bunnell 1982;Thompson and Turner 1982;Rutberg 1987;Risenhoover and Bailey 1988;Bowyer 1991;Keech et al 2000;Côté and Festa-Bianchet 2001) is the overriding factor in the timing of births.…”

Timing of seasonal migration in mule deer: effects of climate, plant phenology, and life-history characteristics

“…Body fat is the primary energy reserve of the body and is related to multiple demographic factors of large herbivores including timing of breeding (Cook et al 2004), pregnancy and twinning rate (Keech et al 2000, Stewart et al 2005, gestation length (Garcia et al 2006), birth mass (Keech et al 2000, Lomas and, and survival (Cook et al 2004. Although demographic factors may be directly affected by animal nutrition, we documented that behavioral decisions regarding when to migrate during autumn also had nutritional underpinnings for mule deer.…”

Elk Calf Survival and Mortality Following Wolf Restoration to Yellowstone National Park

“…Decreased juvenile survival has been correlated with lower birth mass in studies of elk, red deer, and other ungulates (Guinness et al 1978, Nelson and Woolf 1987, Keech et al 2000, Ditchkoff et al 2001, Jenkins and Barten 2005, including northern Yellowstone elk calves during 1987-1990(Singer et al 1997. Poor habitat and higher adult female densities can also lead to reduced calf growth rates and reduced overwinter survival (Guinness et al 1978;Cook et al 1996Cook et al , 2004.…”