Below are GIS grids that provide estimates for hydrogen stable-isotope ratios for North American annual and growing-season precipitation. Estimates are based on averages from a limited number of years and sample sites and should be used with discretion.  Data and methods used to produce grids are described in:

Meehan, T.D., J.T. Giermakowski, and P.M. Cryan. 2004. GIS-based model of stable hydrogen isotope ratios in North American precipitation for use in animal movement studies. Isotopes in Environmental and Health Studies 40:291-300. PDF.

Note that JPEG image files are approximately 1.5 MB. These files can be downloaded and viewed with any graphics viewer. The GIS files are much larger, approximately 330 MB per img file and 25 MB per rrd file. When downloading GIS files, put the img, rrd, and xml files in the same directory. GIS files can be opened and used without modification by ERDAS Imagine software. GIS files can also be opened with ESRI ArcMap version 8 and higher.

Jpeg images
growing-season precipitation (color)
growing-season precipitation (grayscale)
annual precipitation (color)
annual precipitation (grayscale)

Growing-season precipitation grid
gro_seas_ddp.img (data file)
gro_seas_ddp.rrd (pyramid file)
gro_seas_ddp.img.xml (FGDC metadata)

Annual precipitation grid
annual_ddp.img (data file)
annual_ddp.rrd (pyramid file)
annual_ddp.img.xml (FGDC metadata)

More mapping links
Precipitation grids can be combined with land cover and species range layers in a GIS to limit queries to within certain habitats and regions.  Below are a links to remotely sensed land cover layers for North America and species range layers for birds and mammals of the western hemisphere.
Land cover maps
Species range maps

Links to other isotopes-in-precipitation resources
Gabe Bowen’s water isotopes page
Global network of isotopes in precipitation (GNIP)