How we research
Where do the numbers come from?
Figures on this site are researched from published sources, cited here as plain text: the Cornell Lab of Ornithology NestWatch nest box dimension tables and Project FeederWatch guidance, the U.S. Fish and Wildlife Service publication "Homes for Birds", the Audubon Society hummingbird nectar guidance, the American Bird Conservancy window collision guidance, and manufacturer specification sheets for every product we list.
Every calculator labels its basis. Published figure means a table value or a physical relationship (nest box dimensions, the 1:4 nectar ratio, binocular exit pupil). Rule of thumb means a widely used backyard guideline (squirrel jump distance, window distance, nectar change interval).
How are products chosen?
- Every product comes from a live Amazon listing, with its real title, image and price. We never invent a product, a price or a specification.
- Roundups give three genuinely different picks: beginner, intermediate and expert, with who should skip each.
- We do not test products in person. Picks are based on specifications, manufacturer documentation and patterns in verified owner reviews.
- Prices change constantly; the price shown is from the last check and the button shows the current one.
What if something is wrong?
Tell us on the contact page and we will correct it.