Study

Supplementary feeding advances laying in red-winged blackbirds Agelaius phoeniceus and may increase polygyny at two ponds in Washington, USA

  • Published source details Wimberger P.H. (1988) Food Supplement Effects on Breeding Time and Harem Size in the Red-Winged Blackbird (Agelaius phoeniceus). The Auk, 105, 799-802

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 randomised, replicated and controlled experiment around two lakes in Washington state, USA, in 1981 (Wimberger 1988), found that red-winged blackbirds Agelaius phoeniceus from territories supplied with supplementary food laid eggs 8-13 days earlier than blackbirds from control (unfed) territories, for first, second, third and fourth nests of the year (20 territories studied). Each lake was divided in half, with one half provided with sunflower seeds from the 4th April. The average number of females in each territory was increased by feeding on one lake (average of 9.0 females/territory on fed territories vs. 6.5 females/territory on controls, eight territories studied) but not the other (average of 5.2 females/territory on fed territories vs. 4.7 females/territory on controls, 12 studied).

     

Output references

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, terrestrial mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 17

Go to the CE Journal

Subscribe to our newsletter

Please add your details if you are interested in receiving updates from the Conservation Evidence team about new papers, synopses and opportunities.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape Programme Red List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Bern wood Supporting Conservation Leaders National Biodiversity Network Sustainability Dashboard Frog Life The international journey of Conservation - Oryx British trust for ornithology Cool Farm Alliance UNEP AWFA Butterfly Conservation People trust for endangered species Vincet Wildlife Trust