In the case of some of these birds, however, raw population numbers might not be telling the entire story. According to Ryan, follow-up research in Missouri has found that although the population numbers for the blackbirds may be high, that doesn't mean that their numbers are increasing. In fact, there is some evidence that CRP land is causing a slight decrease in blackbird populations. Everybody just assumed that because of CRP habitat, the number of blackbirds was increasing. Ryan says there may be a simple explanation.
Blackbirds nest either in wetlands or in grasslands.