CRBO efforts to study and save the Rusty Blackbird
The International Rusty Blackbird Technical Working Group is a collaboration by state, federal and nongovernmental organizations that seeks to determine the cause of the rapid decline of Rusty Blackbird populations.
The decline of Rusty Blackbirds is one of the most severe population crashes of any North American bird species, yet the causes largely remain a mystery. Little is known about the birds' biology, ecological requirements and other characteristics. "Rusties" are very shy birds that fear new or strange phenomena. This, combined with the fact that they breed in northern boreal wetlands and winter in certain swamps in the southeastern U.S., makes Rusty Blackbirds difficult to study and capture.
Possible reasons for dwindling Rusty Blackbird populations:
- Habitat loss on the wintering grounds, both from conversion of wooded wetlands to farmlands and from urban development.
- Altered habitat on the breeding grounds. Most other boreal wetland nesting bird species are also in decline - birds such as Lesser Scaup, Lesser Yellowlegs, Solitary Sandpiper and others. Global warming is causing changes in the hydrology, water chemistry and plant communities in the boreal wetlands.
- Acid Rain affecting wetlands on the birds' breeding or wintering grounds.
- Mercury contamination on the wintering grounds. Rusty Blackbird's diet consists of a higher proportion of minnows, aquatic insects and other water creatures than other blackbirds. This results in a greater risk of Methylmercury accumulation in the Rusty Blackbird's tissues. Mercury contamination is known to interfere with the breeding success rate of certain birds and with neurological development in young birds.
- Other contaminants such as pesticides or other chemicals may be partly responsible.
How we are Helping:
As part of field research efforts, IRBTWG member organizations have been netting/trapping wintering birds in the Southeast Atlantic Coastal Plain. Blood and feather samples have been obtained from captured birds for analysis. Each bird is also being banded with standard aluminum bands, as well as colored plastic band combinations. The goal is to attempt to recapture and resight banded birds in future years to learn more about their winter movements, site fidelity from year to year, longevity and other aspects of the Rusty Blackbird's life history.
2007 marked the second winter in a row that CRBO personnel (Chris Snook and Nathan Dias) have been assisting the field teams with their efforts in coastal South Carolina.
2008 was a year for general field surveys, organizing a Rusty Blackbird workshop / conference at ACE Basin National Wildlife Refuge for state + federal + university biologists and managers, and applying for grants for field efforts in 2009 and beyond.
CRBO's assistance to the Rusty Blackbird Technical Working Group has consisted of:
- Providing background and historical information, as well as current status and locations of significant Rusty Blackbird flocks in coastal South Carolina.
- Help selecting optimum netting/banding locations and specific subsites. Optimum banding locations were selected for: Rusty Blackbird presence, ability for the team to work without disturbance, suitable areas for mist-netting, and other factors.
- Help gaining permission for mist-netting and banding on public and private lands. - Site preparation (lane clearing, bait preparation and placement) and equipment loan (mist-netting poles, spotting scope...)
- Help deploying, monitoring and clearing mist-nets, as well as help recording data, handling Rusty Blackbirds and 'banding' captured birds (prior to releasing them unharmed).
- Help organizing the 2008 Rusty Blackbird Conference / workshop
How you can help:
Submit your Rusty Blackbird sightings to eBird
Photos - click for larger image:
LEFT PHOTO: 1 female, 2 male Rusty Blackbirds RIGHT PHOTO: Diane Licata and Kevin Wright preparing to take blood and feather samples and then band Rusty Blackbirds.
LEFT PHOTO: 1 female, 1 male Rusty Blackbird RIGHT PHOTO: CRBO's Chris Snook handling a Rusty Blackbird.
The following 3 photos show the process of setting up mist nets in a patially drained floodable corn field used for duck hunting. The flooded corn field is located on a private plantation in the ACE Basin region of South Carolina. This location set the record among all eastern and western IRBTWG field teams for the most Rusty Blackbirds captured at a single site.
LEFT PHOTO: A view of mist nets set up in some nice habitat at Donnelley WMA.
MIDDLE + LEFT PHOTOS: A view of a Cypress-Tupelo swamp beside a netting site at Savannah National Wildlife Refuge.
