DREHERSVILLE – Although the overall numbers for most species were down for the 2013 Autumn Hawk Watch at Hawk Mountain Sanctuary, counter and research biologist Dave Barber said it is not necessarily a cause for concern.
Each year from mid-August through mid-December, sanctuary biologists and personnel, volunteer workers and private individuals count and record the sightings of migrating raptors as they fly south pass the lookout stations. A few volunteers may continue to count at North Lookout sporadically though January, and the best days for seeing migrants are those with strong northwest winds.
Final officials totals for the 2013 count was 15,271 raptors, which is more than 4,700 less than the 2012 final count total of 19,983. For the official counters at North Lookout it was a season of waiting for the big flight to materialize, but unfortunately for most species that big flight never occurred.
Of the 16 species counted, 12 were below their 10-year average and counts for some species like Northern Harriers and the Cooper's Hawks were as much as 46 percent below the 10-year average. Barber said the season was not all doom and gloom, however, as Turkey and Black Vultures and Bald and Golden Eagles had higher than average counts, the 20 Golden Eagles counted on November 3 was the fourth-highest one-day total in Hawk Mountain history, the 21 Bald Eagles seen on the August 23 was the 10th highest, and also counted was the first Rough-legged Hawk in five years on October 30.
Why so many species were below average is unknown, but many of the ridge watch sites in Pennsylvania, such as Waggoner's Gap in Carlisle, had similar below average counts, whereas valley sites such as Rose Tree Park in Media, had more average counts. A lack of strong cold fronts that keep the migrants on the ridge could partially explain the totals.
One year of below-average counts, however, is no cause for alarm. It is the ability to look at season totals across years and detect potential population declines illustrate the value of collecting long-term data like is done at Hawk Mountain.
In addition to the 15,271 raptors counted this fall, 80,369 non-raptors including 501 butterflies and 385 dragonflies were counted. Ranking in the top five species counted are Canada Geese (27,541), Cedar Waxwing (7,929), Common Grackle (6,319), Snow Goose (4,017) and Red-winged Blackbird (2,951), and the most unusual bird was a Bohemian Waxwing seen on September 2, only the sixth record for this northern species.
Overall, warbler and vireo counts seemed to be lower than average, although there were several excellent morning flights and some exceptional single-day species counts. Fifteen species of warblers were counted September 15, including a record high 60 Blackpoll Warblers, another 13 species were counted September 7 and September 5 a record-high 43 Cape May Warblers passed.
Other highlights included 8,584 Canada Geese on Thanksgiving, 50 Tundra Swans November 29, 484 Barn Swallows August 16, 82 Ruby-crowned Kinglets October 22 and a five-day total 2,582 Cedar Waxwings counted between September 3-7.
Starting this spring, Hawk Mountain researchers will identify a minimum of three Broadwing nests in and around Hawk Mountain, and tag for the first time ever up to six juvenile broadwings. Using the latest satellite technology, the birds will be tracked along the entire length of their migration journeys and back.