Record hawk flight highlights fall migration over the Monadnock Region

On a favorable autumn day, the movement of birds over the Monadnock Region can begin with a few distant specks above the ridgelines. Then the specks multiply. Broad-winged hawks circle upward together in columns of rising warm air, forming groups known as kettles. Once they gain altitude, the birds stream south toward the next source of lift, conserving energy during journeys that can eventually carry them to Central and South America. That annual migration produced a historic spectacle at the Pack Monadnock Raptor Observatory this fall, where observers counted more than 6,000 migrating hawks in a single day. "In some cases, we see just amazing spectacles of huge numbers of hawks, like we saw last week," said Phil Brown, bird conservation director and land specialist at the Harris Center for Conservation Education. "The biggest day of raptor migration in our 22 years happened on the 19th, with over 6,000 hawks flying by." Most were broad-winged hawks, a forest-dwelling species Brown described as smaller and less conspicuous than the familiar red-tailed hawk. "They're a little bit more secretive," Brown said. "They're a little more in the woods, and they're smaller — not as flashy — but they're super common." The flight was an extraordinary example of a much larger seasonal movement taking place over backyards, forests and fields across the Monadnock Region. Fall brings the year's greatest abundance of birds because adults are traveling alongside young birds hatched during the breeding season, Brown said. Many are headed toward wintering grounds south or west of New Hampshire. Their paths are shaped partly by geography and weather, which can funnel large numbers through migration corridors. "We're lucky enough to have ridges and valleys, and some of our best concentration points are along those features," Brown said. Pack Monadnock is especially well positioned to make that movement visible. The 2,290-foot mountain in Miller State Park sits near the northern end of the Wapack Range, a roughly north-to-south ridgeline aligned with the direction many birds travel in the fall. Raptors use rising air to reduce the amount of energy required for their long journeys. Thermals develop when the sun warms the ground, causing air to rise. On windy days, air striking a mountain ridge is pushed upward, creating another form of lift. "Many raptors, especially, are using the lift that comes off of those mountains," Brown said. "With a nice northerly wind, the wind is giving the birds lift that helps them fly with more ease and get farther in their migrations on a daily basis." Northwest winds, particularly after a cold front, can produce some of the observatory's most active migration days. Yet the species passing overhead change as autumn progresses. Broad-winged hawks dominated the September count, but their numbers decline sharply toward October as most continue south through the Appalachians. Sharp-shinned and Cooper's hawks, peregrine falcons, merlins and American kestrels can continue moving through the region in early October. Later in the season, observers begin watching for American goshawks, golden eagles and larger flights of red-tailed and red-shouldered hawks. The Harris Center staffs the observatory daily, weather permitting, from Sept. 1 through Nov. 20. Counters record the species and number of migrating raptors, along with weather conditions and other observations. Those records are submitted to HawkCount, an international database used to examine migration and population trends. The value of the count becomes clearer when one season is viewed alongside decades of observations. During the 2025 season, counters spent more than 605 hours at the observatory and recorded 8,581 migrating raptors representing 15 species. Broad-winged hawks accounted for 5,821 birds, approximately 68 percent of the season's total. That was an improvement over the record-low 2024 count but remained below the observatory's long-term average. Some species showed more encouraging results. The 2025 count included 170 bald eagles, continuing a long-term recovery that may now be leveling off. Counters also recorded 122 northern harriers, just three shy of the observatory's seasonal record, and an above-average 196 American kestrels. Other findings raised questions. American goshawks finished well below their long-term average, while red-shouldered and red-tailed hawks also produced lower-than-average counts. The report noted that warmer late-fall weather may allow some raptors to remain farther north when prey is still available, delaying or changing their migration. A low count does not always mean that a population has declined. Wind and weather can push birds toward a different ridgeline, causing them to bypass a monitoring site. That variability is one reason standardized observations collected over many years — and across many locations — are important. Pack Monadnock is one of more than 200 sites in the Americas that monitor migrating raptors each year, Brown said. It is currently New Hampshire's only full-season hawk watch with paid staff covering the entire migration period. The site also regularly produces some of the Atlantic Flyway's stronger counts for certain species. Its northern location and mountainous geography give visitors a chance to see birds that are uncommon elsewhere in the state, including the golden eagle and American goshawk. "Visitors from all over the state and beyond will come out and look for some of these species that they don't get to see too many of elsewhere," Brown said. The record broad-winged hawk flight has passed, but migration is far from over. Different raptors will continue crossing the region into November, often joined by migrating songbirds, waterfowl, monarch butterflies and dragonflies. Visitors can reach the observatory platform by a short trail from the Pack Monadnock summit parking lot or by hiking from the base of Miller State Park. Advance day-use reservations are strongly recommended, particularly during busy fall weekends.