This layer represents *generalized* boundaries of Important Bird Areas (IBA) in Canada.  IBAs, in Canada and elsewhere, are evaluated and designated on the basis of internationally criteria.  The polygons contained in the dataset meet these criteria and are therefore deemed significant at the national, continental, or global level.  In Canada, IBAs are not legally recognized entities and therefore do not have any regulatory status.  Nevertheless, they are extremely useful for conservation planning for birds.  Polygon boundaries were digitized on-screen in ArcView GIS 3.2 by using NTDB 1:50K or 1:250K digital layers for reference.  If NTDB coverage was not available (e.g., far north), the Digital Chart of the World (1:1M) was used.  The boundaries of IBAs in this dataset are intentionally generalized to reflect the importance of the surrounding ecosystem on the values present within IBAs.  For example, small islands supporting colonies of seabirds might be buffered by 1 or 2 km to form an IBA.  Boundaries for a very small minority of IBAs were available in paper form as part of IBA conservation plans that had been developed previously.  In such cases, we visually estimated their boundaries against the NTDB or other base layers.  Many IBAs are already recognized as other types of protected areas, e.g., National Wildlife Areas, National and Provincial Parks, Migratory Bird Sanctuaries, conservation reserves, and so on.  In these cases, we used digital boundaries from other sources (e.g., WWF Canada's Designated Areas Database, Environment Canada's Canadian Conservation Areas Database) as reference points when digitizing IBA boundaries.  Please cite as follows:  Bird Studies Canada and Nature Canada.  2004.  Important Bird Areas of Canada Database.  Port Rowan, Ontario:  Bird Studies Canada.  To access the Canadian IBA directory: http://www.bsc-eoc.org/iba/ibasites.html.  Full metadata for this layer:  http://www.bsc-eoc.org/website/metadata/caniba_poly.xml