The impact of hand-rearing on the morphology and physiology of captive and wild grey partridges (Perdix perdix) and capercaillies (Perdix perdix) was studied in three feeding trials conducted under laboratory conditions, and two comparative studies between wild and captive birds. Finally, wild and hand-reared grey partridges from several localities in Europe were sampled and the control region 1 of mitochondrial DNA was sequenced to reveal genetic variation between populations, as well as to compare wild and captive stocks.
Wild capercaillies had heavier pectoral muscles, hearts, livers and gizzards, longer small intestines than hand-reared ones, and a higher cytochrome-c oxidase activity in muscle and heart. Invertebrates were essential to the growth, primary and temperature regulation development in grey partridge chicks. Fish was not sufficient to replace invertebrates in the diet. A change in diet from commercial to natural decreased the assimilation efficiency in the grey partridge. It also increased the mass of gizzard reflecting the need for greater grinding ability. Of hepatic P450 enzymes used in this study 7-ethoxyresorufin-0-deethylase and 7-pentoxyresorufin-0-deethylase differed between wild and hand-reared birds. Coumarin-7-hydroxylase activity was higher in grey partridges than capercaillies. Diet differences may have caused these differences. Quebracho tannin added to the diet lowered caecal nitrogen, and elevated tannin excreted in feces. Otherwise its effects were slight.
Mitochondrial control region revealed 14 variable sites between two main lineages detected. Nucleotide and haplotype diversities varied greatly between populations. The markedly deep divergence between the two lineages indicated most probably post-glacial recolonisations from geographically isolated refuges. In Finland, wild birds represented the eastern lineage, while the farmstock represented the western lineage. Surprisingly little trace, contrary to expectations, from the large-scale releasing of imported partridges could be seen in the European populations.