SOUTH SALT LAKE — The seasons have changed, and that means it's the time for millions of migratory birds to be traveling to or through Utah in search of important resources, such as food.
Some bird species have already begun this journey while others are still on the way from as far as Central America and South America, said Cooper Farr, director of conservation for Tracy Aviary.
But what you may not know is that many bird species — including flycatchers, sparrows, tanagers, thrushes and warblers — typically make their migration journey at night. As Herb Wilson, a professor emeritus of biology at Colby College, wrote in 2011, these species travel at night mostly for survival purposes.
"Most of these birds are denizens of woods and other sheltered habitat," he wrote. "These birds are not extremely agile fliers so need dense habitat to avoid bird predators. Migration at night has at least three advantages. Birds do not have to worry about falcon or hawk attacks. Second, the air in the atmosphere is usually less turbulent than during the day. Lastly, the air is cooler at night."
Frances Ngo, a conservation outreach biologist for the Tracy Aviary Conservation Science Program, added that birds like to use the stars, landmarks, magnetic fields or other visual queues to migrate. Experts like Ngo and Farr say these types of journeys can be threatened by light pollution at night, which interferes with their normal patterns.
Light pollution, which is "inappropriate or excessive use" of artificial light, can disorient these traveling birds and draw them into cities and other communities, where they end up colliding with windows or buildings, according to the Tracy Aviary Conservation Science Program.
"Birds will be (pulled) off course or collide with windows and lit-up structures," Ngo said. "We do know we see an increase in (dead) birds, like songbirds, on the sidewalk or along the building sides."
That's why the Tracy Aviary launched "Lights Out Salt Lake" a few years ago. The initiative, which was first in partnership with the group Dark Sky SLC, encourages residents and businesses to turn off all unnecessary lights from 11 p.m. to 6 a.m. during migration seasons, which are generally March through May and August through October.
"This is the peak time when birds are migrating through the cities, and it's an event where we want to let people know how they can help birds along the way," Ngo added.
Aviary officials celebrated the launch of this year's "Lights Out" campaign with tours through the Tracy Aviary Jordan River Nature Center Thursday morning.
"I guess the ultimate goal of this 'Lights Out' program that we did it to try and make sure we can make our area as safe as possible for the birds that are migrating through the area," said Farr, guiding a tour of guests through the Jordan River Parkway.
Utah is home to plenty of important natural habitats for migrating birds. That includes areas like the Jordan River Parkway and sanctuaries like the Bear River Migratory Bird Refuge, Ouray National Wildlife Refuge, and Farmington Bay Waterfowl Management Area.
Farr explained birds like to follow waterbodies during their migration paths because water comes with many resources. That's why the Jordan River is a valuable migration area.
"So, like different types of plants and insects and all sorts of things that they can feed on as they are coming up the river," she explained. "It's actually a really, really diverse spot for birds and it gets a little underappreciated in the area."
Utah's historic and current geographic importance during migration seasons is why the "Lights Out" program was created, especially as population growth in the region has led to more artificial light. The program urges businesses to evaluate lighting needs in parking lots, pathways, stairwells and buildings, and see which lights could be turned off at night both indoors or outdoors.
It also encourages homeowners or renters to turn off outdoor lights, such as porch lights or path lighting, from 11 p.m. through 6 a.m. Experts say people can install motion sensors on outdoor lights for any safety purposes. Residents are also encouraged to use warm/white bulbs that are less than 3,000 kelvins and draw blinds to keep indoor light from flooding outside.
"That will really cut down on light pollution and let birds continue along their way," Ngo said.
In addition to turning off unneeded lights at night, Cooper said there are several other ways people can help migrating birds. That includes leaving fresh water and high protein bird food in yards or putting decals on windows to avoid bird-window collisions.
Contributing: Sean Moody, KSL TV