EMBRYONIC OXYGEN-CONSUMPTION IN THE GREAT SPOTTED WOODPECKER (DENDROCOPOS-MAJOR) - INFLUENCE OF DEVELOPMENTAL MODE AND INCUBATION PERIOD

Oxygen consumption of two eggs of the Great Spotted Woodpecker was mea sured with a two-channel oxygen analyzer using an open flow system. Th e embryogeny of oxygen consumption nearly follows an exponential equat ion with the exception of a 7-hour plateau phase on day 9 of incubatio n. During this period the embryos consume ca. 4 ml O2 x min-1. For a g iven fresh egg mass the eggs of woodpeckers have unusually short incub ation periods (10 days measured vs. 17 days expected). Thus a comparis on of the embryonic metabolism with that of species having long incuba tion periods but similar egg sizes shows the influence of a fast embry onic development on avian enbryonic energetics. The total embryonic me tabolism of the Great Spotted Woodpecker amounts to 0.9 kjx g-1 fresh egg mass which is half as much as the value for most other birds (ca. 2 kJ x g-1).