Oregon Breeding Bird Atlas
Methods
Project Duration
Most state atlas projects have accomplished their objectives in about
five years, and at the outset the Oregon project, the steering committee
decided to conduct our project for five years, 1995-1999. A longer period
would have likely increased the adequacy of coverage of many of the atlas
units but was deemed undesirable because (1) changes in land cover and climate
that influence bird distributions would be more pronounced and would confound
data interpretation, (2) valuable momentum and interest might diminish,
(3) some atlasers might find it less rewarding to participate due to the
increasing difficulty of finding or confirming species not reported previously
from an atlas unit, and (4) several important data users were eager to use
the results.
Project Materials
Every person who asked to participate in the project was sent
an "atlasing packet" containing the following materials:
1. Handbook This 14-page guide provided instructions and described the protocols.
2. Unit-Specific Field Card This was a checklist of species believed most likely to occur in the particular atlas unit that an atlaser wished to cover. Multiple, location-specific cards were sent to volunteers who requested an opportunity to cover several units. Cards were updated and reprinted annually to include observations from previous years of the project. This process was extremely effective in getting atlasers to focus on finding species that had not been found, thus improving the completeness of the inventory.
3. Maps. These color maps showed boundaries of the hexagons and squares, overlaid on roads and geographic features. They were photocopied with permission from the Oregon Atlas and Gazetteer published by DeLorme Publishers. The maps were at a scale of 1:300,000 (1 inch = 4.8 miles) for eastern Oregon and 1:150,000 (1 inch = 2.4 miles) for western Oregon. We updated the maps each year to show (with color-pen highlighting) roads and trails that had been visited by project participants in prior years of the project, and encouraged participants to survey birds in areas not previously visited. Digital maps showing the roads and trails covered in each atlas unit are highlighted in red in the zoomed-in hexagon maps on this CD.
In addition to the above, each participant received a Casual Observations field card and a Statewide Field Card. Atlasers used these to record observations from atlas units for which they had not received a Unit-Specific Field Card, and for atlas units in which they observed only a few species during a brief visit (e.g., while traveling through to another area.)