| Instead of our winter visitors that left us for more northern areas, we now have grackles, red-wings and cowbirds. |
| Studies have revealed that as many as 90 percent of the vireo nests in Texas and Oklahoma have been invaded by cowbirds. |
| However, cowbirds exhibit density-dependent selection of wooded edge versus prairie interior habitats in the region. |
| Blackbirds, cowbirds, and mockingbirds are common companions throughout most of the year. |
| The probability of parasitism may vary among hosts because differences in their behaviors assist cowbirds in locating nests. |
| The only characteristic that separated parasitic cowbirds from their nonparasitic relatives was an increase in eggshell thickness. |
