Paranatal oxygen consumption and respiratory frequency in the Laysan Albatross

The oxygen consumption and respiratory frequency of Laysan Albatross eggs were measured during the different phases of pipping (paranatal period) and in hatchlings. The initial phase of pipping--penetration of the aircell of the egg by the embryonic beak--coincided with the beginning of pulmonary ventilation, the embryo rebreathing aircell gas, but it did not result in a statistically significant increase in oxygen consumption. The second phase of pipping--star-fracture of the shell (external pipping)--was the shortest (25 h) of the three phases of pipping, and it did not result in a significant increase in either oxygen consumption or respiratory frequency. The longest phase of pipping (65 h)--the pip-hole phase--represented 54% of the total duration of pipping, and it was accompanied by significant increases in oxygen consumption and respiratory frequency. When the eggs hatched, the oxygen consumption increased further but respiratory frequency diminished significantly. It was calculated that the paranatal period, which represented 7.9% of the total incubation period of the egg, accounted for 37.2% of the total oxygen consumption of the egg.