Ferguson, a volunteer at Bear River Migratory Bird Refuge and nearby Antelope Island State Park, was one of several birding experts on hand last Saturday to help educate visitors who came to see the “D-Line,” a less-traveled route extending from the refuge’s regular auto tour loop to I-15 in Willard.

Once a year, the refuge opens up the D-Line to offer the public a chance to explore an area that is usually off-limits. The refuge managed by the U.S. Fish and Wildlife Service encompasses nearly 80,000 acres of marsh, open water, uplands and alkali mudflats.

Jennifer Wright, wildlife biologist at the refuge, said the timing of the annual “Behind the Gates” day coincides with the sensitive nesting season. Of the more than 200 species of birds that use the refuge, 67 use it as nesting grounds during spring.

“We do it once a year before nesting season really kicks off,” Wright said. “Killdeer and snowy plovers will nest on these side roads, and we don’t even drive down them during nesting season unless there’s an emergency.”

Love, or maybe just the innate urge to reproduce, was in the air Saturday as the avian mating season was in full swing. A group of several Northern shoveler ducks flew overhead in pursuit of a lone female as Ferguson talked about volunteer opportunities at the refuge.

“Those bad boys are after her,” he remarked. “They’re all wanting to date.”

Canada geese pairs bobbed along the water, closely guarding their newly hatched broods. Recently arrived American avocets and White-faced ibis jockeyed for position as they worked to established their nesting territory for the season. Tree swallows darted through the air, feasting on the clouds of midges that have emerged with the onset of warmer weather.

Saturday’s event was organized “just to encourage the public to see more,” Wright said.

“The auto tour route is nice, but this gives the public a different view,” she said. “This is a perfect time of year. A lot of birds have just migrated here, or they’ve been here for a few weeks and are establishing territories.”

Behind the Gates day draws not just bird enthusiasts, but also plenty of hunters who come to scope out the landscape to get a sense of what conditions they might encounter during duck-hunting season later in the year.

“We usually get a good mix of birders and hunters,” Wright said.

Those who want to drive the D-Line will have to wait until next year. In the meantime, the refuge’s auto tour loop is open year-round. The 12-mile loop is located 12 miles west of I-15 from exit 363, making for a 36-mile round trip from the freeway. The auto tour loop is open daily, conditions permitting, from sunrise to sunset and access is free to the public.