Figure 2.
Correlation between Eastern Bluebird breeding densities (i.e., the number of occupied nest boxes per area of useable habitat within a 300 m radius of each box) and yolk testosterone concentrations in the fourth egg.
Correlation between Eastern Bluebird breeding densities (i.e., the number of occupied nest boxes per area of useable habitat within a 300 m radius of each box) and yolk testosterone concentrations in the fourth egg.