Effects of calcium supplementation on the development and survival of black tern Chlidonias niger chicks in the Bargerveen, Drenthe, Netherlands

  • Published source details Beintema A.J., Baarspul T. & de Krijger J.P. (1997) Calcium deficiency in black terns Chlidonias niger nesting on acid bogs. Ibis, 139, 396-397


This study is summarised as evidence for the following.

Action Category

Provide calcium supplements to increase survival or reproductive success

Action Link
Bird Conservation
  1. Provide calcium supplements to increase survival or reproductive success

    A small control trial conducted during the 1996 breeding season on an acid bog in the north-eastern Netherlands (Beintema et al. 1997) found that six of eight black tern Chlidonias niger chicks force-fed with supplementary calcium fledged successfully, whereas all 11 unsupplemented chicks died before fledging. The two unsuccessful supplemented chicks died early (within five days), whereas the unsupplemented chicks all showed skeletal deformities and significantly lower rates of weight gain. Commercially-available calcium pills, were given to chicks three times a week, providing a total of approximately 700 mg of calcium over the study period.


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