Northern Prairie Wildlife Research Center
The New Mexico Breeding Bird Atlas Project
Mapping Squares and Blocks
The state of New Mexico has been divided into 156 atlas squares that are 50 kilometers on a side. Each of these squares contains 100 5-km × 5-km blocks. The 5-km × 5-km block is the basic unit of the atlas project. Each block is further divided into 1-km squares called kilos for determining relative abundance (see Estimating Relative Abundance).
Statistical Priority Blocks
Because it is impossible to survey the entire state of New Mexico for nesting birds, some blocks are assigned based on a random sampling design. Such blocks are called statistical priority blocks and are essential for making the result of the atlas valid for the state as a whole. Each mapping square contains at least one statistical priority block. Additional statistical priority blocks will be assigned if enough people volunteer over the life of the atlas project.
Habitat Priority Blocks
In addition to the statistical priority blocks, habitat priority blocks are assigned to gain information on specific habitats. For example, riparian vegetation (creek- and stream-side habitats) is a relatively rare and valuable habitat for birds in New Mexico, so the atlas project will sample them more heavily than some other habitats. Habitat priority blocks will also include areas of particular ornithological interest, or areas managed to serve as baselines against which to measure avian change or differences in the surrounding, less-protected landscapes. Examples of other habitat priority blocks are national park areas, wilderness areas, and wildlife refuges. Your regional organizer will be aware of the location of these blocks in your area.
Blocks not given statistical or habitat priority are called supplementary. While the importance of getting statistical priority and habitat priority blocks completed cannot be overemphasized, there is no restriction from working in supplementary blocks. In the early years of the atlas project statistical and habitat priority blocks will be emphasized. Volunteers are welcome to survey supplementary blocks, but not at the expense of statistical priority or habitat priority blocks. For example, if your residence is not in a priority block, you could survey in the nearest priority block as well as in the supplementary block in which you live.
A regional organizer will provide to each volunteer a photocopied or electronically reproduced topographic map of the block to be surveyed. The topo map shows roads, streams, ponds, buildings, and contour lines. Shaded gray or green-colored areas depict the location of forests. Especially note roads, trails, and major landmarks such as mountains, ridges, streams, forested versus open areas and man-made structures that will help you locate the boundaries of your block on the map and help you find your way around the block. Geographic features also signal different types of habitats that you need to visit. Forested and open areas are obvious habitat differences, but you may also find habitat changes with elevation, on different steepnesses of slope, on north- versus south-facing slopes, and in areas adjacent to streams, lakes, and marshes. Consider making additional copies of your map in case it gets wet or damaged by use in the field. Additional photocopies will also be helpful if you wish to sketch or make notes on the location of habitat types, individual birds, trails, names of landowners, etc.
In some instances, topographic maps are several years old, and some features may have changed. Thus, there may be other maps you may find useful for getting information about your block. On public lands, National Forest and Bureau of Land Management maps often cover a larger area and may have more current road information. Your regional organizer can direct you to additional maps to supplement the map provided. A county map is useful in planning access to the different parts of the block. A county plat book that shows ownership and parcel size may be useful in obtaining permission to enter private land. If you find access too difficult or the terrain too rough, talk to your regional organizer about getting assigned a new block.