long. This represents an average area of 3200 sq. miles (8436 sq. km) per latilong. 

 Latilongs along the Canadian border are 5.4 percent smaller than those along the 

 Wyoming border. 



These nearly-uniform units form a global grid across middle latitudes that provide 

 conformity between states and nations. The U.S. Fish and Wildlife Service's Breeding 

 Bird Survey is based on this latilong grid. So successful was Skaar's early use of the 

 latilong as a biogeographic aid (Skaar 1969, 1980), that several neighboring states 

 have used latilongs for mapping bird distribution (Stephens and Sturts 1991; Kingery 

 1987; Oakleaf et al. 1982) and other vertebrate groups (Thompson 1982; Findholt et 

 al. 1981). 



The map on the back cover depicts the 49 latilongs and 185 quarter latilongs in 

 Montana. This includes L48 and L49 which cover small portions of southwest Montana 

 previously excluded from the first three editions. Also enclosed in this edition is a 

 latilong map that has been superimposed over a state highway map. This is an extra 

 aid that will permit accurate location of the quarter latilong (QLL) where an observation 

 is made. For finer resolution when sightings are near boundaries and for reporting rare 

 birds, please refer to the Forest Service, BLM, and USGS topographic maps to 

 accurately determine the correct QLL location. 



Quarter Latilongs 



The most obvious change from the Third Edition is the use of quarter latilongs (QLL). 

 QLL units are created by dividing each latilong unit into four quarters at the 30 minute 

 degree mark between each degree of latitude and longitude. Each QLL cell retains the 

 number of the latilong cell with the addition of a letter (A,B,C, or D) ordered left to right 

 (Fig. 1). Thus, latilong 25 is now broken into 4 QLLs: 25A, 25B, 25C, 25D (see p.7). 

 Each of the latilongs has the Third Edition data listed in the center (Example "X" Fig. 

 1). All of the new (post-Third Edition) data are presented in the quarter latilong 

 positions. 



Figure 1. Quarter Latilong Letter Code Sequence. 



A 



C 



-X- 



B 



D 



We recognize that the maps displayed in this edition are "busy" and may be confusing 

 at first glance. However, a sufficient amount of new data did not exist to adequately 

 represent the distribution of most birds in Montana. The Third Edition data are retained 

 in the center of the latilong so that there is continuity between the old and new formats. 

 In the Fifth Edition (1995) only the quarter latilong values, based on data submitted 

 since Third Edition data, will be displayed. In the past, contributors have focused on 



