Big Mountain Pass is located on the Salt Lake and Morgan County lines along SR-65. At 7,420' it sits right in a belt where numerous habitats meet. Among Utahns it is known for two things. It is on the original route of the Mormon pioneers who crossed it in 1847 on their way to the Salt Lake Valley; and it is a great place to watch the sunset over a sliver of Salt Lake visible from the area. Where the highway tops out there is a large gravel parking area on the south side of the road. The Great Western Trail coming from the north crosses the road here, and continues to southeast from the east side of the parking area. There are restrooms and several benches here. Aside from the trail heading southeast, there is also one that follows the southwest slope down into Mountain Dell Canyon, and another going northeast into Upper East Canyon. Down the west side and on the hills to the north the habitat is generally mixed oak woodland; some aspen and conifer can be found as well. To the south and southwest is a huge patch of aspen that stretches for miles both directions. On the northeast and east sides are mid elevation coniferous forest. Some willow and riparian like habitat exists here minimally. There is also shrubsteppe on the west slope leading down the canyon. The county line splits the parking area in half and is marked along the road. For a while this was one spot but in order to accurately split the data there are not spots on both side of the county line--this matters because generally you are birding on one side or the other. The details for the the Salt Lake County side are below--the MorganCounty birding information can be found here.
Big Mountain is one of my favorite birding locations in Salt Lake County. The birding on the way up, while there and down the other side into East Canyon makes for a great span of habitats and locations and although nothing terribly out of the common really shows up here, the resident breeding birds are easy gets on almost any trip. Form mid May through July early in the day or in the evening SWAINSON'S and HERMIT THRUSH can both be heard singing in the woods here. WESTERN TANAGER, LAZULI BUNTING, and BLACK-HEADED GROSBEAK add some bright color to the trees. MOUNTAIN BLUEBIRD are often heard calling overhead, or seen on the north side of the road. HOUSE WREN chatter is a constant, while DUSKY FLYCATCHER can usually be found calling in the woods. MACGILLIVRAY'S WARBLER can be found in the dense thickets on the slopes here. Both GREEN-TAILED and SPOTTED TOWHEE are present at the pass as well. Overhead VIOLET-GREEN SWALLOW are usually seen as well. Hiking the trails into the hills you can access other habitat and species typical of the conifer. Both species of KINGLET, AMERICAN THREE-TOED WOODPECKER, PINE GROSBEAK, and STELLER'S JAY have all been observed. The pass is often used for owling and 5 species have been found between both sides of the pass. FLAMMULATED OWL is a common breeder here, while NORTHERN SAW-WHET OWL is occasionally found. NORTHERN PYGMY-OWL show up from time to time, and are encountered more often south of here on the Great Western Trail. Finally, COMMON POORWILL can usually be heard on the west slopes here after dark. The pass can be a busy location with city slickers coming up for a quick drive away from the city; bikers taking a break; or various other people that show up here. I like to hike the trails even just a few hundred yards to get away from the pass if there are people around. Most of the birds mentioned above are easy get on any trip here.
From I-80 exit 134 in Parley's Canyon head north onto SR-65 and follow this 8.2 miles past Mountain Dell and Little Dell Reservoir through Mountain Dell Canyon. The road switchbacks and has a couple sharp turns before eventually reaching the pass with a parking area on your right.