KAYTEE Western Regional Blend attracts more backyard birds. The science behind this extraordinary mix is based on seed preferences and visual perception of songbirds typically found in the Western United States. Our regional seed blends have been independently field tested by researchers at leading universities and proven to attract more birds than either black oil sunflower seed or other non-regional blends.* Based on results of field tests of KAYTEE Western Regional Blend against black oil sunflower seed and other, non-regional blends. Individual results will vary due to local environmental factors including bird migration and distribution, terrain, landscaping and weather.