December 21, 2017

Autumn 2017 Migration Wrap-Up

Broadwing in flight by Bill Moses

In autumn 2017, Hawk Mountain tallied 17,012 raptors in over 1000 hours of effort. The overall total was 6% below the 10-year average.

Four species were spotted in above-average numbers, including turkey vultures, bald eagles, broad-winged hawks, and peregrine falcons. The broad-winged hawk total count, 10,726, was 36% above average, with four days of 1000 plus broadwings in September. This above average count for the species helped buoy the total raptor count to just 6% below average, despite the very low counts of other species.

Two of Hawk Mountain's most abundant species, the sharp-shinned and red-tailed hawk, were recorded in low numbers, 46% and 52% below the 10-year average respectively. Similar dips in numbers were seen in other regular migrants, as well. Particularly notable was the 90% below average count of the northern goshawk, a species that has declined in numbers for several years; this year's count is the lowest on record.

Some dips in numbers can be attributed to the lack of strong cold fronts that concentrate migrants in October and November, along with the warmer weather in northeastern states. The above average temperatures may have allowed some species to remain north longer, and they may still be seen migrating past the lookouts after the official hawk watch season.

The first bird of the season was a broad-winged hawk, and the last official bird of the season was a juvenile bald eagle. This bookends an impressive season for both species. Counters also spotted a rare, light morph rough-legged hawk on November 11.

Non-raptor migrants also were in lower numbers than average with 51,954 other birds counted, compared to the average of over 65,000. A total of 68,112 non-raptors were counted, including 2,434 butterflies and 707 dragonflies. Counters tallied almost 2,200 monarch butterflies this season, including a one-day count of 270. Other highlights include a couple of "red-letter" warbler days and 1,334 tree swallows on September 26. The most abundant non-raptor species for the 2017 season was the Canada Goose, with 19,931 counted.

For count details for the 2017 autumn season, visit

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