Green River State Park is located in the town of Green River and consists of a nine-hole golf course, a campground shaded with cottonwood trees, and a boat ramp into the actual Green River which borders it on the east side. The campground which covers the southwest 1/3 of the park is a huge migrant trap with the biggest trees is the area. Along the river the dominant species of tree is russian olive, with various other trees and shrubs including: willow, salt cedar, cottonwood, and other deciduous trees. The riparian habitat is along a natural north-south migrant route following the river. Sand bars, and beaches here provide more habitat, along with the obvious river habitat which ranges form shallow to deep enough to accommodate diving birds. There are actually 5 ponds on the golf course as well, all of which can be viewed from roads or trails. While the boat ramp provides the best views of the open water on the river, you can walk along the shoreline north and south as well to bird the river. As this is a state park there is an entrance fee.
Of the 4 public birding locations in Green River, the State Park as of this writing has the biggest species list, and the most number of visits. It is also the biggest location, and easiest to access with the most varied habitats. On the flip side it is also the busiest site due to the campers, golfers, and other outdoor enthusiasts that want to venture far enough form the big city, but not quite to the great outdoors. In any event the bird species here are varied, and the biggest draw in my opinion is that the camp site is a huge migrant trap. The large stand of trees is a centerpiece to the park. Year round you'll find AMERICAN ROBIN, HOUSE FINCH, both LESSER and AMERICAN GOLDFINCH, and NORTHERN FLICKER. Other species that are present year round may include HORNED LARK, COMMON RAVEN, and WESTERN MEADOWLARK. Both GREAT HORNED and WESTERN SCREECH-OWL call the woodlands here home. During the winter months DARK-EYED JUNCO and WHITE-CROWNED SPARROW move in. On the river in the winter months COMMON and HOODED MERGANSER are present, while other waterfowl might be seen as well. During spring and fall migration a variety of waterfowl, shorebirds, and waders are possible along the river. During spring and fall migration you could put together a pretty good day list with the combo of the waterbirds and the migrants.
Even with the birders that have visited the migrant list isn't enormous. There are a handful of surprise species that have shown up here late during the fall months including BROWN CREEPER, MOUNTAIN CHICKADEE, TOWNSEND'S SOLITAIRE, WHITE-BREASTED NUTHATCH, and RED-NAPED SAPSUCKER. During the breeding season there are a few species that make a stop here worthwhile, including BLUE GROSBEAK, YELLOW-BREASTED CHAT, ASH-THROATED FLYCATCHER, along with the more common LAZULI BUNTING, BLACK-HEADED GROSBEAK, and BULLOCK'S ORIOLE. I suspect September into October could be very productive here for migrants. Spending some time scouring the grounds could easily push the area list over 100 species by adding various sparrows and warblers that absolutely pass through.
From the intersection of SR-19/Main Street and Broadway in Green River, head east on Main Street for .4 miles. Take a right on Green River Blvd and go south for .5 miles to the park entrance. Take a left into the park and you can continue .2 miles to the parking area at the boat ramp and go birding from here.