 Smaller birds were processed in a demountable bench, protecting from wind, dust, and desiccation |
 Measurements were taken, the fresh weight was determined and the bird was morphologically and parasitologically investigated |
 The brain was conserved separately from the carcass |
 The carcass was cut into small pieces and conserved in aluminium containers (they emit no plasticisers as do plastic containers) |
 From larger birds samples from brain and muscle tissue were conserved to determine the relation of DDT-residues of brain vs. carcasse |
 Conservation fluid was formalin. It increases the dry weight of the tissues.The degree of weight increase was determined in laboratory experiments and the obtained weights of desert bird samples corrected |
 In the laboratory the conserved tissues were homogenized |
 The tissue homogenate was spread on clean filter paper |
 After treatment in the drying oven the dry weight of carcasses and brains were determined. Fresh weight - dry weight = water content |
 Lipids were extracted in Soxhlet-apparatuses using petroleum ether pro analysi |
 The solvent was removed from the lipids using a rotary evaporator |
Water content: Fresh weight - dry weight Water index: Percent water content per fat-free dry weight of the complete bird without stomach contents Fat index: Percent fat per fat-free dry weight |
