 |
| Red Wattlebird |
If you live in Canberra, what birds are you likely to see near your home? I have been playing around with different measures of bird abundance to address that question, using data from the Canberra Garden Bird Survey.
The Canberra Garden Bird Survey (GBS) is a community based, volunteer survey that has been run by the Canberra Ornithologists Group (COG) since 1981. Despite its name, it isn't strictly a garden bird survey at all. It is probably better described as an urban bird survey, but even that isn't completely accurate since the survey does include rural residential sites. The survey records bird abundance in sites of about 3.1 ha (31,000 m2) that are around or near where people live or work. Site shape and location are of participants choosing, usually around their home or place of work. Because sites are much larger than typical suburban yards, they include a range of habitats beyond the typical garden, especially where the home is near some kind of edge. Records are weekly throughout the year. The GBS years starts in July and ends in June. For each species observed during each week, the largest number of individuals in the site at the same time is recorded. Sites have come and gone over the 32 years of the survey, usually around 70 - 80 sites per year. Since mid last year I have been the coordinator of the GBS.
For the purpose of addressing the question What birds am I likely to see near a Canberra home I chose a distribution measure, a weekly presence measure and a "best site" weekly presence measure. I used the most recent 3 years of GBS data (from July 2009 to June 2012), and I excluded data from the rural sites, so it is just data suburban from Canberra and Queanbeyan. Using 3 years of data rather than just one gets a few more of the rarities that show up (for example, winter of 2009 was a Yellow-tufted Honeyeater year).
The Canberra Garden Bird Survey (GBS) is a community based, volunteer survey that has been run by the Canberra Ornithologists Group (COG) since 1981. Despite its name, it isn't strictly a garden bird survey at all. It is probably better described as an urban bird survey, but even that isn't completely accurate since the survey does include rural residential sites. The survey records bird abundance in sites of about 3.1 ha (31,000 m2) that are around or near where people live or work. Site shape and location are of participants choosing, usually around their home or place of work. Because sites are much larger than typical suburban yards, they include a range of habitats beyond the typical garden, especially where the home is near some kind of edge. Records are weekly throughout the year. The GBS years starts in July and ends in June. For each species observed during each week, the largest number of individuals in the site at the same time is recorded. Sites have come and gone over the 32 years of the survey, usually around 70 - 80 sites per year. Since mid last year I have been the coordinator of the GBS.
For the purpose of addressing the question What birds am I likely to see near a Canberra home I chose a distribution measure, a weekly presence measure and a "best site" weekly presence measure. I used the most recent 3 years of GBS data (from July 2009 to June 2012), and I excluded data from the rural sites, so it is just data suburban from Canberra and Queanbeyan. Using 3 years of data rather than just one gets a few more of the rarities that show up (for example, winter of 2009 was a Yellow-tufted Honeyeater year).
