We also provide some estimates of mean trend and a ranking of species from most extreme decline to most extreme increase, using the procedures given in Link and Sauer (1996). These results adjust estimates for relative precision, and you can estimate:
These results are based on hierarchical model trend estimates (Link and Sauer 2002).
We group birds based on attributes such as breeding habitat, nest type, migration status, and nest location. If species in the group show consistent trends, and differ from species not in the groups, it suggests that the common feature could be influencing population change for the group. For more discussion on this, click here. For a listing of the species in each guild, click here
Although these data have been processed successfully on a computer system at the USGS Biological Resource Division, no warranty expressed or implied is made regarding the accuracy or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. This disclaimer applies both to individual use of the data and aggregate use with other data. It is strongly recommended that these data are directly acquired from a Biological Resource Division server, and not indirectly through other sources which may have changed the data in some way. It is also strongly recommended that careful attention be paid to the contents of the metadata file associated with these data. The Biological Resource Division shall not be held liable for improper or incorrect use of the data described and/or contained herein.
So, these data are provided "as is" and without any express or implied warranties, including, without limitation, the implied warranties of merchantability and fitness for a particular purpose. Also, use of trade names or commercial products in this home page is solely for the purpose of providing specific information, and does not imply recommendation or endorsement by the U.S. Government.
aTo download a PDF reader, visit http://get.adobe.com/reader.