Study

Effect of additional food on reproductive success in the magpie (Pica pica)

  • Published source details Hogstedt G. (1981) Effect of additional food on reproductive success in the magpie (Pica pica). Journal of Animal Ecology, 50, 219-229.

Actions

This study is summarised as evidence for the following.

Action Category

Provide supplementary food for songbirds to increase reproductive success

Action Link
Bird Conservation
  1. Provide supplementary food for songbirds to increase reproductive success

    A replicated cross-over study in a pine forest site in southern Sweden in 1974-5 (Hogstedt 1981) found that female black-billed magpies Pica pica laid earlier, had larger clutches and laid larger eggs when supplied with supplementary food compared to when no food was provided (average of 3.5 days earlier, an extra 0.56 eggs/clutch and eggs weighing 0.33 g more, ten females studied). Fed pairs were less likely to lose nestlings and had higher fledging success than control (unfed) pairs (88% of 20 fed nests having one surviving nestling and 2.7 fledglings/breeding attempt vs. 48% and 1.3 fledglings/breeding attempt for 32 controls). Supplementary food consisted of 300 g of fish provided in the centre of experimental territories every other day from 15th March until eggs hatched, when it was raised to 600 g. This represents approximately 75% of a pair’s daily requirement before hatching and 65-150% after hatching. Food was also provided in seven territories without magpies, but did not attract any new pairs.

     

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