The similar daily survival rates of nests in CRP and WPA fields indicate that the habitat quality of CRP fields and WPA fields is roughly comparable. More information is needed to provide a fuller picture of how the CRP is affecting trends in grassland birds. Information on temporal and spatial effects is especially useful. As CRP fields age, their attractiveness to certain species may change. Daily survival rates of nests also may change.
Spatial effects are apparent in our censuses and undoubtedly exist on a wider scale.
Finally, we need to integrate results from field studies with trend data from the Breeding Bird Survey. The Conservation Reserve Program and grassland birds. Reynolds, R.E., T.L. Shaffer, J.R. Sauer, and B.G. Peterjohn.