Studying Black Birds at Night Underground!

Abstract from Ibis
7th September 1996

There can be no species so difficult to see in Britain, even though they breed in large numbers, as the Storm Petrel. This tiny seabird forages out at sea and only returns to its breeding burrow at night. Mark Bolton might therefore seem to be crazy to decide to study it in detail - particularly because the birds are also very prone to desert due to disturbance at the nest! However he has published (Ibis, 138, 405-409) the results of a very detailed study using hi-tech artificial burrows within an established colony.

These burrows are made from plastic pipes and allow the birds a nice, cosy nesting place with the additional home comforts of continuous weight recording and metabolic rate measurements. In each of two years, 29 out of 81 burrows were occupied. The Storm Petrels started their incubation bouts at about 31 gms and this was apparently the determining factor for the birds to return and relieve their mate. The incubation bouts often lasted two, three or more days and the birds lost about 1.8 gms per day. From the CO2 measurements the metabolic rate was about 55 kJ per day - this can be accounted for by catabolism of stomach oils. These are the essence of zoo plankton that the petrels use as a take away system for transport of their resources.