Laboratory research on sea-birds
Swennen, C. (1977) Netherlands Institute for Sea Research, Texel
Sea-birds are of scientific interest because of their many adaptations, enabling these originally terrestrial birds to remain in the open sea for long periods in all kinds of weather and exploit the food of the marine habitat. Since these birds spend a considerable time in the boundary-layer between sea and air, and since they are at the top of the food pyramid, they are excellent biological indicators for many forms of marine pollution.
Until recently, long-term experiments in which sea-birds were kept under semi-natural and ecologically satifactory conditions, were not possible for want of the correct zoo-techniques.
In this report an experiment is described which led to a new zoo-technical method for keeping sea-birds in captivity. When they are kept pelagically - which is the natural condition for sea-birds - control of the water surface was found to be essential. The quality of this surface is reflected in the surface tension, which could be kept in the right condition by constant skimming of the water.
Some species known to give poblems in captivity, viz: Guillemots, Razorbills, Puffins, and Kittiwakes were collected as chicks in a colony and used in the experiment. Their development was normal, their average mortality lower than the figures reported for free-living birds. It did not appear necessary to give Alcidae additional vitamins with the food, which consisted of whole, deepfrozen small fish. After three years some birds became sexually mature. Eggs were laid, which were incubated by the parents and from which young birds hatched.
In rehabilitated oil-victims kept under the same conditions for 2 years after recovery, the mortality was five times as high as our own birds.
The new technique makes it possible to carry out all kinds of biological long-term experiments, which cannot be carried out in nature.