Tricolored blackbirds are being banded as part of a statewide effort to identify and document movement patterns and fidelity to breeding colonies. The banding of tricolors began in 2007 and has continued annually, with over 47,800 tricolors banded by autumn, 2011. Thus far, all birds have been banded during the breeding season at sites adjacent to breeding colonies.
The recapture of banded birds has demonstrated strong fidelity to breeding sites and a high degree of colony cohesion, with birds breeding together at one location tending to move as a group to breed together again at a different location. Previously-banded birds tend to be recaptured in groups, a phenomenon that requires an explanation while suggesting that birds are not only breeding site faithful, but that breeding birds may recreate spatial relationships established in one location at subsequent breeding colonies.
In May, 2011 a bird that was color-banded at Delevan National Wildlife Refuge in June, 2009 was observed and photographed in Madera County, providing evidence of a linkage between Central Valley and Sierra foothill breeding locations. And one bird originally banded at Merced National Wildlife Refuge in May, 2001 was recaptured in June at a colony at Delevan National Wildlife Refuge and again in July at a different colony at Delevan National Wildlife Refuge. This is the first time in 5 years of banding that the same individual has been captured at 3 different locations and suggests that some females may be triple-brooded. It also highlights the contributions of National Wildlife Refuges for tricolored blackbird conservation.