PRACTICAL METHODS OF ESTIMATING VOLUME AND FRESH WEIGHT OF BIRD EGGS

摘要: Bird eggs begin to lose weight as soon they are laid but their volume and linear dimensions do not change during incubation. The of an egg can be estimated within 2% from the relationship: Volume = 0.51. LB2, where L is length B breadth (maximum diameter). fresh Weight Kw' LB 2, K w a species-specific constant that determined empirically or calculated published data. Received 25 April 1978, accepted 28 October 1978. IT frequently useful know bird's egg. One reason many aspects biology bird predicted these values used when empirical data lacking. Alternatively, one way detect adaptations unusual situations by comparing observed with for "average" Some parameters metabolic rate (Rahn et al. 1974), incubation period Ar water vapor conductance (Ar daily loss (Drent 1970), surface area, density, shell (Paganelli relation adult body (Huxley 1923-24, Rahn 1975). Additionally, accurate required calculation fractional 1974) estimation age (Westerkov 1950). However, only at time laying because immediately begins diffusion vapor. This proportional 0.74 power 1970) totals about 16% initial end As consequence, while great deal information available on dimensions, there few reliable reports weight. Fortunately, incu- bation, in present paper I show predict Several authors have shown its (Bergtold 1929, Worth 1940, Westerkov 1950, Stonehouse 1963), Preston (1974) suggested more complex approach. In paper, evaluate accuracy which (V) dimen- sions (L length, maximum diameter), using equation: V Kv' 2