Location of Duck Creek Pass Eagle Watch, MT.

Site Description

The Big Belts are a 75-mile long, northwest-southeast trending section of the Rocky Mountains, situated in the Helena-Lewis & Clark National Forest in west-central Montana. The range is bordered to the west by Canyon Ferry Lake, a 35,181 – acre reservoir created by the damming of the Upper Missouri River. To the east of the Big Belts lie the Shields Valley and Crazy Mountains.

Strong, prevailing southwesterly winds constantly buffet the Big Belts. These consistent winds, in combination with the southern Big Belts’ steep, westerly slopes generate powerful updrafts, providing ideal flying conditions for migrating raptors. These persistent updrafts, combined with the Big Belts’ prominent, single ridge at their southern end, concentrate migrating raptors in great numbers during fall migration. (Grayum & Dugan 2017)

Site Topography

The Big Belt Mountains are a section of the Rocky Mountains in the U.S. state of Montana. Situated mainly in the Helena National Forest, the mountains are used for logging and recreation for the surrounding residents. Nearby is Helena, Montana, Canyon Ferry Lake, the Missouri River, Townsend, Montana, and White Sulphur Springs, Montana. The highest point in the Big Belt Range is Mount Edith at 9,504 feet (2,897 m) while the center of the range is 7,385 feet (2,251 m)[1]
The Big Belts lie primarily between the Missouri River drainage to the west and the Smith River drainage to the east. Today, they are traversed by U.S. Highway 12 between Townsend, Montana in the Missouri drainage, and White Sulphur Springs, Montana in the upper Smith River drainage.[2]
The gulches on the western slopes of the Big Belts were noted historically for rich gold placer strikes. The richest was the 1864 and 1865 placer gold strikes in Confederate Gulch, including Montana Bar, which was one of the most concentrated gold placer strikes ever made.[3]
The range takes its name from the fact it is situated in a long belt-like arc. It stretches 75 miles, making it a mid-length subrange of the Rocky Mountains. To the east are the Little Belts and to the south, somewhat continuing this arc, are the Bridger Mountains.

The Belt Supergroup series of rocks, which are primarily Precambrian mudstones, were named after this mountain range and the adjacent Little Belt Mountains. A particularly well-known example of exposed Belt Group mudstones in alternating purplish-red or pale bluish-green layers in the Big Belt Mountains is in Wolf Creek Canyon along Interstate 15 between Helena and Great Falls. While these rocks were named after these ranges of western-central Montana, and are found in them, they are more exposed and better known in northwestern Montana, northern Idaho, and southeastern British Columbia, namely around Flathead Lake, Glacier National Park

Site History

The Duck Creek Pass Eagle Watch was first recognized as a significant migration flyway for Golden Eagles in 2007. In 2014 volunteers documented 284 Golden Eagle in 6.75 hours of observation. Additional counts in fall of 2014 consistently yielded greater numbers of Golden Eagles than any other site in the United States. Location data collected from Golden Eagles equipped with satellite transmitters indicated that a significant number of migrant Golden Eagles, after traversing the length of the Big Belts, migrated directly east to the Crazy Mountain. In fall of 2015 the first standardized scientific count (from 15 September – 3 November) at Duck Creek Pass yielded 2,630 migrating raptors. This is the highest Golden Eagle passage rate known in North America. The Duck Creek Pass site also yielded an astonishing diversity of raptor species as in September of the count season it is possible to see all 17 species of raptors known to migrate through this region. No other western hawk watch site gets this amazing diversity. Full season counts continued at Duck Creek Pass through 2017. (Dugan & Grayum 2016)

Unfortunately, due to extreme early season weather events (primarily snow), lack of funding and coordination the sites effort was greatly reduced in 2018 and 2019. After the 2019 season it was recommended to the Golden Eagle Migration Survey (GEMS) committee and Raptor View Research Institute (RVRI) to move the high elevation count elsewhere. (Seaman 2019)

In the fall of 2020 responsibility of conducting standardized scientific counts was taken up by Montana Golden Eagle Research (MGER).

The Duck Creek Pass Eagle Watch and Cave Knoll Eagle Watch  intend to contribute to the understanding of spring and fall raptor migration (with an emphasis on Golden and Bald Eagles) in western Montana. Since this project is long term it may have the potential to enhance our knowledge of raptor population status and trends. Most importantly, as apex predators, these raptors may serve as critical barometers of overall ecosystem health and human-caused environmental changes (including climate disruption).

Project Description

Standardized scientific counts of migrating raptors may provide valuable information regarding overall population numbers, and if any particular species is in decline.  Based on preliminary fall raptor counts conducted at Duck Creek Pass Eagle Watch it is estimated that this site may yield seasonal count totals of between 2,000 and 4,000 migrant raptors, with approximately half or more being eagles.  The Duck Creek Pass Eagle Watch is designed to determine total migrant raptor numbers and the seasonal timing of passage of the birds.