Growth-related changes in salt gland mass in gentoo and chinstrap penguin chicks
The salt gland is a well-developed osmoregulation organ in marine birds, and its relative size often reflects an individual’s feeding environment and osmoregulation capability. The development and functions of salt glands have been described for the Adélie penguin (Pygoscelis adeliae), but this information has been poorly documented in the other two pygoscelid species: gentoo (P. papua) and chinstrap penguins (P. antarcticus). To describe the growth-related changes in salt gland masses in relation to chick growth, we measured the wet mass of the salt glands collected from dead gentoo and chinstrap chicks during the early breeding period. The mass of the salt glands was linearly proportional to their body measurements, especially to body mass, in both species, and no significant difference was detected between the two species. Penguins are obligate marine dwellers throughout their life cycle, and the development of the salt gland in penguin chicks suggests that their ability to regulate dietary osmotic stress begins at an early stage of development after hatching. Furthermore, the linear relationship between the gland mass and body mass also suggests that the osmoregulation capability may continue to develop as penguin chicks grow. This descriptive note provides novel and quantitative information on the early developmental pattern of salt glands in gentoo and chinstrap penguins.
Ainley D.G., Wilson P.R., Barton K.J., Ballard G., Nur N. & Karl B. 1998. Diet and foraging effort of Adélie penguins in relation to pack-ice conditions in the southern Ross Sea. Polar Biology 20, 311–319, doi: 10.1007/s003000050308.
ATCM (Antarctic Treaty Consultative Meeting) 2019. Revised Management Plan for Antarctic Specially Protected Area no. 171, Narębski Point, Barton Peninsula, King George Island. Working Paper 16. Antarctic Treaty Consultative Meeting XLII and Committee for Environmental Protection Meeting XXII, 1–11 Jul 2019. Prague.
Barton K. 2018. MuMIn: multi-model inference. R package version 1.40.4. Accessed on the internet at https://CRAN.R-project.org/package=MuMIn on 1 July 2019.
Burnham K.P. & Anderson D.R. 2004. Multimodel inference: understanding AIC and BIC in model selection. Sociological Methods & Research 33, 261–304, doi: 10.1177/0049124104268644.
DeVink J.-M.A., Gilchrist H.G. & Diamond A.W. 2005. Effects of water salinity on growth and survival of common eider (Somateria mollissima) ducklings. Auk 122, 523–529, doi: 10.1093/auk/122.2.523.
Dosch J.J. 1997. Salt tolerance of nestling laughing gulls: an experimental field investigation. Colonial Waterbirds 20, 449–457, doi: 10.2307/1521595.
Douglas D.S. 1968. Salt and water metabolism of the Adélie penguin. Antarctic Bird Studies 12, 167–190.
Ellis R.A., Goertemiller C.C. Jr., DeLellis R.A. & Kablotsky Y.H. 1963. The effect of a salt water regimen on the development of the salt glands of domestic ducklings. Developmental Biology 8, 286–308, doi: 10.1016/0012-1606(63)90031-9.
Ensor D. & Phillips J. 1972. The effect of age and environment on extrarenal salt excretion in juvenile gulls (Larus argentatus and L. fuscus). Journal of Zoology 168, 119–126, doi: 10.1111/j.1469-7998.1972.tb01342.x.
Gutiérrez J.S., Dietz M.W., Masero J.A., Gill Jr R.E., Dekinga A., Battley P.F., Sánchez‐Guzmán J.M. & Piersma T. 2012. Functional ecology of saltglands in shorebirds: flexible responses to variable environmental conditions. Functional Ecology 26, 236–244, doi: 10.1111/j.1365-2435.2011.01929.x.
Janes D.N. 1997. Osmoregulation by Adélie penguin chicks on the Antarctic peninsula. Auk 114, 488–495, doi: 10.2307/4089249.
Johnston J.W. & Bildstein K.L. 1990. Dietary salt as a physiological constraint in white ibis breeding in an estuary. Physiological Zoology 63, 190–207, doi: 10.1086/physzool.63.1.30158161.
Kokubun N., Lee W.Y., Kim J.H. & Takahashi A. 2015. Chinstrap penguin foraging area associated with a seamount in Bransfield Strait, Antarctica. Polar Science 9, 393–400, doi: 10.1016/j.polar.2015.10.001.
Lishman G.S. 1985. The food and feeding ecology of Adélie penguins (Pygoscelis adeliae) and chinstrap penguins (P. antarctica) at Signy Island, South Orkney Islands. Journal of Zoology 205, 245–263, doi: 10.1111/j.1469-7998.1985.tb03532.x.
Marples B. 1932. The structure and development of the nasal glands of birds. Journal of Zoology 102, 829–844, doi: 10.1111/j.1096-3642.1932.tb01565.x.
Pinheiro J., Bates D., DebRoy S., Sarkar D. & R Core Team 2015. nlme: linear and nonlinear mixed effects models. R package version 3.1. Accessed on the internet at http://CRAN.R-project.org/package=nlme on 1 July 2019.
R Core Team 2014. R: a language and environment for statistical computing. Vienna: R Foundation for Statistical Computing.
Schmidt-Nielsen K. 1960. The salt-secreting gland of marine birds. Circulation 21, 955–967, doi: 10.1161/01.CIR.21.5.955.
Schmidt-Nielsen K. & Kim Y.T. 1964. The effect of salt intake on the size and function of the salt gland of ducks. Auk 81, 160–172, doi: 10.2307/4082766.
Siegel-Causey D. 1990. Phylogenetic patterns of size and shape of the nasal gland depression in Phalacrocoracidae. Auk 107, 110–118, doi: 10.1093/auk/107.1.110.
Simon E. 1982. The osmoregulatory system of birds with salt glands. Comparative Biochemistry and Physiology 71, 547–556, doi: 10.1016/0300-9629(82)90203-1.
Staaland H. 1967. Anatomical and physiological adaptations of the nasal glands in Charadriiformes birds. Comparative Biochemistry and Physiology 23, 933–944, doi: 10.1016/0010-406X(67)90354-4.
Thomson J. & Morley N. 1966. Physiological correlates of habitat selection in Australian cormorants. Emu 66, 17–26, doi: 10.1071/MU966017.
Trivelpiece W.Z., Trivelpiece S.G. & Volkman N.J. 1987. Ecological segregation of Adélie, gentoo, and chinstrap penguins at King George Island, Antarctica. Ecology 68, 351–361, doi: 10.2307/1939266.
Volkman N.J., Presler P. & Trivelpiece W. 1980. Diets of pygoscelid penguins at King George Island, Antarctica. Condor 82, 373–378, doi: 10.2307/1367558.
Woodin M., Michot T. & Lee M. 2008. Salt gland development in migratory redheads (Aythya americana) in saline environments on the winter range, Gulf of Mexico, USA. Acta Zoologica Academiae Scientiarum Hungaricae 54, 251–264.
Authors contributing to Polar Research retain copyright of their work, with first publication rights granted to the Norwegian Polar Institute. Read the journal's full Copyright- and Licensing Policy.