Birds are big business. That may come as a surprise to people who have never given much thought to the warm-blooded vertebrates who fly over their heads every day, but tens of millions of people have a passion for birds.

A 2016 survey from the U.S. Fish & Wildlife Service found that more than 45 million people in the United States watch birds around their homes and away from home every year. While statistics aren't as current in Canada as they are in the United States, past studies have indicated birding is wildly popular among Canadians, with roughly 30 percent going wildlife-viewing while on out-of-town trips of one or more nights. That positively affects the economy, contributing billions of dollars to the tourism industry in both the U.S. and Canada every year.

While birding trips can help birdwatching enthusiasts see birds they otherwise may never see in person, bird feeders can be a great way to bring more birds into your own backyard. Choice of bird feeder can affect just which birds come to your back yard, and the following are some bird feeder options for birding enthusiasts to consider.

· Window feeders: Small and easily attached to windows with suction cups, window feeders are easy to maintain and bring birds right to your window. Birds that visit window feeders stand in the seed while feeding, so they must be cleaned and refilled on a daily basis.

· Tray or platform feeders: The online birding resource All About Birds (allaboutbirds.org) notes that tray feeders attract the widest variety of seed-eating feeder birds. That makes them ideal for birding enthusiasts who want to attract a variety of birds to their properties. Tray feeders are simply platforms that hold seed and provide a place for birds to stand while they eat. All About Birds recommends tray feeders with screened, rather than solid, bottoms, as these trays promote complete drainage. Frequent cleaning is necessary with tray feeders, as bird droppings can quickly soil seed.

· Hopper or house feeders: These feeders are enclosed and feed seed out through the bottom. Hopper feeders are great for people who don't want to be bothered with daily maintenance, as they can hold several pounds of food at one time, greatly reducing the number of times homeowners will need to refill them. In addition, hopper feeders don't need to be cleaned as often as other feeders. However, All About Birds notes that hopper feeders, which need to be thoroughly cleaned roughly once per month, are harder to clean than other feeders.

· Tube feeders: Tube feeders deliver seeds to birds through screens or ports. Small perches attract birds to tube feeders, making these ideal for small birds. Some tube feeders contain perches designed for birds that can feed upside down, potentially attracting a greater variety of birds to your backyard. But All About Birds notes that seed can collect on bottom-most feeding ports, providing a breeding ground for mold and bacteria. As a result, tube feeders should be inspected and cleaned regularly.

Bird feeders can draw an array of birds to your backyard.