Chick growth in albatrosses: curve fitting with a twist
Huin, N.; Prince, P.A.. 2000 Chick growth in albatrosses: curve fitting with a twist. Journal of Avian Biology, 31 (3). 418-425. 10.1034/j.1600-048X.2000.310318.xFull text not available from this repository.
We present a new type of equation to describe the growth patterns of procellariiform seabirds and other species whose chicks characteristically lose mass towards the end of the rearing period. Our equation is based on the Gompertz curve; our principles are also applicable to logistic and von Bertalanffy curves. From our model, five coefficients can be derived to characterise the patterns of growth. These are: growth rate, peak mass and age at which it is attained, loss rate and an index describing the overall shape of the curve. We illustrate the use of this new equation with data collected, using automated weighing platforms, on six years of chick growth of Black-browed Diomedea melanophris and Grey-headed D. chrysostoma albatrosses at Bird Island, South Georgia. In comparison with Grey-headed Albatross, Black-browed Albatross chicks grow at a faster rate and to a higher peak mass; they also reach their peak mass at an earlier age, and lose mass at a faster rate in the mass recession period. However, in both species, chicks reached peak mass when 72% of the rearing period had elapsed; within species, only this did not vary between years. This new equation not only enables the period of mass recession to be incorporated into growth analysis, but, because it does not require assumptions about asymptotic mass, greatly facilitates inter-species comparisons.
|Programmes:||BAS Programmes > Pre 2000 programme|
|Date made live:||28 Nov 2012 08:16|
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