![]() For the purpose of this article, I wanted to focus on bands that have been re-sighted by an everyday observer I have removed band recovery data points where the bird was recaptured by other researchers, captured due to illness, disease, or starvation, birds with transmitters (since the location is known, it is easier to go out and look for specific individuals), and other miscellaneous sightings (example: a bird that was brought to a rehab center and the outcome was unknown). It wasn't until 2003 that we received the first report of a band on a Redtail that was read while the bird was still alive. GGRO's first documented band recovery was in 1984, of a Redtail found dead in north Manchester, Calif. Slight imperfections in math due to minor errors in recovery database need to be addressed.Īll Redtails banded (metal band only, or metal and color-banded) between 1983-2018ġ983-2012 all Redtails banded before color-banding startedĢ013-2018 all Redtails banded after color-banding startedĨ% (Rate will continue to increase with time) We realize that sampling year and recovery years will vary, and further analysis is beyond the scope of this article. We wanted to compare sampling methods: pre- and post-color banding years. The data reflected here use the sampling date. * Multiple sightings/encounters of the same bird were removed. The metal bands are more durable, whereas a color band can degrade over time and break off. When it comes down to it, the metal bands issued by BBL are more important because they help us track birds banded all over North America through time, using a system common to all North American researchers, with the data collected and stored in a central location. Each metal band receives a unique eight or nine-digit code-like a social security number, but for a bird. BBL manages more than 77 million archived banding records and more than 5 million encounter records. BBL is a scientific government agency, established in 1920, that supports the collection, archiving, management, and distribution of information from banded birds in North America. The metal bands we use at GGRO are issued by the Bird Banding Laboratory (BBL), which is part of the US Geological Survey (USGS). YEARĪ common question I get after explaining the benefits of color bands is: "Why don't you just use color bands instead of the metal bands? Sounds like you only need color bands." This means that a Red-tailed Hawk or Cooper's Hawk encountered in California wearing one of these specific color bands was banded by GGRO volunteers during fall migration. For our programs' research, Redtails receive either a green with black code or lavender with white code color band, and Cooper's Hawks receive a green color band. The goal is to avoid duplicating work by our colleagues across the state and to reduce the disturbance to the raptor. ![]() GGRO coordinates with California Department of Fish and Wildlife (CDFW) and other raptor researchers in California to determine a researcher-specific color and alphanumeric code. Color bands are easier to read than the metal bands, which increases the potential for information return.Ĭolor bands, also known as auxiliary markers, are usually made from plastic or metal and placed on the leg opposite the one that receives the aluminum USGS band. The goal was to increase the recovery rate of banded birds, and to spur public interest in our local raptor populations. In 2013, Chris Briggs started a two-year pilot study to examine the efficacy of using color bands on two species of hawks: Red-tailed Hawks and Cooper's Hawks. One of the reasons for this increase, besides the large number of Redtails moving through the Marin Headlands, was the focus on teaching all GGRO site leaders how to place color bands on birds. That is almost twice as many color bands as we put out in 2017. In 2018, 197 of these Redtails received a color band along with the federal metal band. If you were a Golden Gate Raptor Observatory (GGRO) volunteer, you might have enjoyed this sight from Hawk Hill, or maybe you shook your fist in the air at them from a blind as they took turns stooping on each other in the wind. On any given day, an observer could regularly spot 10-15 Redtails riding the wind uplift on Slacker Hill. ![]() The 2018 field season ended with 342 Redtails banded-almost 100 Redtails above our 10-year average. Red-tailed Hawks! This season was full of them.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |