Year: 1993
Type: article
Abstract: A new fat scoring technique for small birds is introduced using 31 classes (nine main classes with up to four subclasses each; Fig. 1).In contrast to many other methods, fat score and respective fat load (as determined by the Soxhlet method) correlate very well.Furthermore, variability in the calculated regression lines for nine different species is low.This effective new method can easily be learned by handling approximately 100 individual birds and substantially improves precision of studies on fat-deposition in migratory birds.UNA NUEVA CLASIFICACI•)N, CON MULTI-CATEGOR•AS, PARA LOS DEP•SITOS DE GRASA EN AVES CANORAS Sinopsis.--Sepresenta una nueva t•cnica para clasificar los dep6sitos de grasas.La misma utiliza 31 clases, de las cuales 9 son principales, y 6stas a su vez tienen un mfiximo de cuatro subclases cada una (Fig. 1).A diferencia de otros m•todos, la clasificaci6n de la grasa, y su respectiva carga de grasa (como es determinada por el m6todo Soxhlet), se correlacionan muy bien.Mils afin, la variabilidad en el cfilculo de llneas de regresi6n para nueve especies de aves canoras, result6 bajo.Este nuevo m6todo es fficil de aprender con una muestra de aproximadamente 100 aves y mejora sustancialmente la precisi6n de estudios sobre dep6sitos de grasa en pfijaros migratorios.Subcutaneous fat deposits of birds can be estimated visually.Different authors (Davidson 1984, Pettersson and Hasselquist 1985) have developed a series of classification methods to estimate visible fat deposits (here "fat score").These methods, however, are rather rough and so far the accuracy of the various techniques has not been investigated (Blem 1990), although fat scores determined by different authors are, to some extent, convertible.Most of the fat score techniques use only 4-7 classes (Bernis 1966, Busse 1970, Busse and Kania 1970, Cherry 1982, Frelin 1978, Fry et al. 1970, Helms and Drury 1960, Wolfson 1945).I developed a much finer scale of 31 classes (Fig. 1) during studies in the long-term monitoring program of migratory bird populations (MRI-Programme) of the Vogelwarte Radolfzell (Berthold and Schlenker 1975, Kaiser 1992).This method was developed to increase the precision and accuracy of estimating fat scores.A more precise estimation of visible fat deposits may enable one to calculate actual fat load more accurately in future studies as well as to determine precisely physiological capabilities of birds, such as flight range and overnight or overwinter survival.The new scoring method was tested on the following points: 1) the correlation between visible fat deposits and the actual amount of stored fat; 2) interspecific variability; 3) accuracy (i.e., repeatability); and 4) "user friendliness," particularly, how fast the method can be learned and how easily it can be applied.246
Author: Andreas Kaiser
Institutions: Max Planck Society, Max Planck Institute for Ornithology
Language: English
Topic: Avian ecology and behavior
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1176366596