Seasonal variation in growth of greater snow goose goslings: the role of food supply

Abstract

Even though growth rate is an important fitness component, it is still controversial to what extent parent birds adjust the timing of offspring hatch to natural variations in food supply to maximize offspring growth. We studied the role of food availability in explaining inter- and intra-seasonal variation of growth rate in goslings of greater snow geese over 5 years. The peak of hatching generally coincided with the peak of food availability. However, early-hatched goslings usually grew faster than birds hatched at the peak, which in␣turn grew faster than late-hatched goslings, although this phenomenon was not observed in all years. There was considerable variation in growth rate among the five years, the smallest goslings produced in the best year (1991) being larger than the largest goslings of the poorest year (1994). We developed three indices of food availability, based on the cumulative availability of plant biomass and nitrogen content during the growth period, and showed that the cumulative exposure to nitrogen biomass explained up to 43% of variation (intra- and inter-annual) in body size just before fledging. In years with good feeding conditions, early-hatched goslings had access to more nitrogen during their growing period than those hatching on or after the peak and they grew faster. In years of lower food availability, early-hatched goslings had no detectable advantage over peak- or late-hatched birds for access to protein-rich food and no seasonal decline in growth rate was observed. These results confirm the critical role of food supply in the seasonal variation of growth rate in Arctic-nesting geese.

Density dependence and phenological mismatch: consequences for growth and survival of sub-arctic nesting Canada Geese

“…Forage plant quality peaks early in the growing season, when nitrogen concentrations are highest and cell wall contents are lowest, i.e., more digestible, and then declines as the season progresses Raveling 1986, Manseau andGauthier 1993). Some studies have shown that peak nitrogen concentration can precede hatch by 2-3 weeks for both Arctic (Lepage et al 1998) and Subarctic nesting geese (Cadieux et al 2005). Although Canada Geese on Akimiski Island appeared to track plant phenology, i. e., there was a positive correlation between date of hatch and NDVI 50 , they often did not initiate nests early enough to fully keep pace with advanced plant phenology in early springs (i.e., not a perfect or 1:1 correlation) suggesting a potential mismatch (Clausen and Clausen 2013).…”

“…The seasonal decline in forage quality and negative consequences of hatching relatively late within a year compared with conspecifics suggest that differences in hatch dates of as little as a week can result in detectable declines in gosling growth (Cooch et al 1991a, Sedinger and Flint 1991, Lindholm et al 1994, Lepage et al 1998. Person (2001) demonstrated experimentally that late hatched goslings could not compensate for poor forage quality by increasing intake rates and were lighter at 31 days posthatch compared to those that hatched earlier.…”

Early Nutrition Causes Persistent Effects on Pheasant Morphology

“…In our experiment, we only manipulated dietary content, not food availability. Some other studies have found effects of dietary content on subsequent morphology (Boag 1987;Richner 1989;Dahlgren 1990;Larsson and Forslund 1991;Lepage et al 1998). In contrast to these studies, we only manipulated diet during the earliest part of the ontogeny.…”

“…In nature, intrasexual size/ quality differences between individuals born in different habitats (e.g., Ulfstrand et al 1981;Richner 1989) or belonging to different cohorts (e.g., Larsson and Forslund 1991;Witzell 1991) in the same population have been attributed to varying growth conditions. Systematic differences between habitats (e.g., Larsson and Forslund 1991) or years (e.g., Lepage et al 1998) in food availability caused by, for example, density dependence (Cooke et al 1995), variation in weather conditions (Witzell 1991), or timing of breeding (Sedinger et al 1995) may produce these effects.…”

Migratory connectivity in Arctic geese: spring stopovers are the weak links in meeting targets for breeding

“…Migratory birds face the challenge of producing a clutch as soon as possible after arrival on the breeding grounds, since the prospects for progeny decline rapidly with advancing date (Sedinger and Raveling 1986;Sedinger and Flint 1991;Lepage et al 1998;Prop et al 2003;Bêty et al 2003Bêty et al , 2004. Especially in demanding environments still in the grip of winter, the nesting female will face a shortage of foraging opportunities locally and may depend instead on nutrients garnered elsewhere along the flyway and sequestered in the body (notably stores of fat and protein) in order to meet her time schedule.…”