Dietary calcium limits size and growth of nestling tree swallows Tachycineta bicolor in a non‐acidified landscape

Abstract

2005. Dietary calcium limits size and growth of nestling tree swallows Tachycineta bicolor in a non-acidified landscape. Á/ J. Avian Biol. 36: 127 Á/134.Much previous research has focussed on the role of food supply in determining the growth and the survival of avian offspring. More recently, acid deposition in some ecosystems has demonstrated that in addition to energy, birds also need to acquire sufficient nutrients such as calcium to be successful. Whether procurement of adequate levels of calcium can limit reproductive success in areas that have not been impacted by acid rain remains equivocal. We tested whether calcium affected reproductive success of tree swallows Tachycineta bicolor by feeding extra calcium to nestlings during the brood-rearing period. Our manipulation did not enhance the survival of offspring, however, provisioning of extra calcium resulted in nestlings showing enhanced rates of growth of mass (all nests) and of ninth primary flight feathers (nests with after-second year female parents), compared to control nestlings. Calcium supplementation also resulted in nestlings having longer feathers and tarsi at age 16 days, and there was evidence that some nestlings receiving extra calcium were heavier at 16 days old. As offspring that have faster growth, or that are in good condition at fledging, often survive better after leaving the nest, these results suggest that calcium availability can limit fitness. Our results are noteworthy because our experiment was conducted in an area with abundant soil calcium where acid deposition has not occurred. The role of calcium in limiting the reproductive performance of avian species may therefore be more pervasive than previously thought.

Effects of Small Increases in Corticosterone Levels on Morphology, Immune Function, and Feather Development

“…For example, limiting access to important food resources can reduce the growth rate of nestlings (Dawson and Bidwell 2005) and alter song development in adults (Nowicki et al 2002). Hormones can have an effect as well; for example, corticosterone reduces the amount of pheomelanic coloration in developing barn owls Tyto alba .…”

Individual variation and environmental context in avian life-history evolution: An experimental approach using mountain bluebirds (Sialia currucoides).

“…feather growth) later in nestling development. It is also not surprising that neither rate of growth nor length of tarsus in this study was influenced by availability of dietary carotenoids, because avian skeletal growth is limited by the availability of other nutrients, namely calcium (Dawson and Bidwell 2005). Interestingly, however, a recent experimental study investigating the effects of blow flies on nestling performance in eastern bluebirds breeding in Pennsylvania did not report similar effects on tarsus growth in this species, despite considerably higher parasite loads in control nests relative to my study population (Hannam 2006).…”

Nesting Success of Western Bluebirds (Sialia Mexicana) Using Nest Boxes in Vineyard and Oak-Savannah Habitats of California

“…Previous research by Jedlicka et al (2013) using different primer sets (LCO1490 and HCO2198) found isopteran DNA (Armadillium vulgare) in 12 out of 13 fecal samples from Western Bluebird nestlings in Napa and Sonoma County vineyards. Armadillium vulgare is a calcium-rich food source (Ouyang and Wright 2005) and consequently may be an important component of bluebird diets during the breeding season (Tilgar et al 1999, Dawson andBidwell 2005). Clarke et al (2014) show that ZBJ-ArtF1c and R2c primers used here do not provide good coverage for Isoptera, provide excellent coverage for both Diptera and Lepidoptera, and adequate coverage for Hemiptera, Orthoptera, Coleoptera, and Hymenoptera.…”