Supplemental feeding: possible negative effects on black-billed magpies

  • Published source details Reese K.P. & Kadlec J.A. (1984) Supplemental feeding: possible negative effects on black-billed magpies. Journal of Wildlife Management, 48, 608-610.


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 small study from January-March in 1979-1980 in Utah, USA (Reese & Kadlec 1984), found that juvenile black-billed magpies Pica pica that established nest sites closer to supplemental food stations experienced higher rates of nestling starvation than nests further away. Very few adult magpies visited food stations. Dominant juvenile males, however, established nests significantly closer to food stations. Of seven nests within 100 m of food stations, six experienced nestling starvation while only one farther than 100 m did. Supplementary feeding did not enhance clutch (6.4 and 6.4 eggs/nest) or brood (5.0 and 4.8 nestlings / nest) size between nests closer to food stations (16 nests) and those further away (13 nests). Similarly, mean clutch initiation was not significantly different between treatments. The authors point out that supplementary feeding can serve as a proximate stimulus to commence nesting on sites that are not inherently of good quality. Food stations were provisioned with beef bones or black-tailed jack rabbit Lepus californicus carcasses.


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