Research Project on Cavity-nesting Birds

A number of cavity-nesting birds have declining populations. These include the Red-headed Woodpecker, Northern Flicker, and Purple Martin. Other species continue to need human assistance to maintain or increase their populations (Eastern Bluebird is a prime example). One factor implicated in the population declines of these cavity-nesting birds is “interference competition” with the European Starling and House Sparrow. Since 2003, participants in Wisconsin and other states assisted with a multi-year research project, which has the objective of determining the effect of starlings and house sparrows as competitors for nest cavities. This research required collecting observations at existing nest cavities or nest boxes. New nest boxes for various species (especially the Northern Flicker) were constructed and monitored as part of this project.

I provided participants with forms on which to record observations at natural cavities or nest boxes (bluebird, tree swallow, or martin houses included, of course) of interspecific interactions between starlings or house sparrows and any other cavity-nesting species. My objective is to assess whether and how often starlings or house sparrows disrupt the nesting cycle and/or take over cavities or boxes, and this can include interfering with any native-species pair, such that they do NOT successfully nest, whether or not the starling or house sparrow pair does so successfully. I asked participants to gather data for at least two nesting seasons, beginning with spring 2003, or spring 2004, but incidental data is also welcome.

This project will not be adding new observation data from 2006, but observations from 2003-04-05 not yet submitted are needed and welcome. Your assistance would be greatly appreciated. If you would like to participate, please email me at iltlawas@earthlink.net, or, if you do not have internet access, please use the mailing address below. I will supply further information and add your name to the list of possible cooperators. Thanks in advance for your help.

William P. Mueller
Cavity-nesting Birds & Competition Study
1242 S. 45 St.
Milwaukee, WI 53214