2016 Bradbury Mountain Spring Hawkwatch Season In Review

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The 10th annual Bradbury Mountain Spring Hawkwatch wrapped up on May 15th, bringing a remarkable season to a close. Although I did go up for two hours to hope for a vagrant Mississippi or Swallow-tailed Kite on the 20th, netting five migrants (2 Sharp-shinned Hawks and 1 each of Broad-winged Hawk, Cooper’s Hawk, and Merlin. All immatures as expected on the late date). It was worth a try!

Anna Stunkel, a College of the Atlantic graduate and veteran of the Lucky Peak hawkwatch in southwestern Idaho, was the 2016 Official Counter, and she did an incredible job. A tireless observer and interpreter, she introduced hundreds of visitors to the project, and to our numerous local Bald Eagles! While Jeannette and I covered her days off – when rain didn’t do the job for us – or whenever else we got a chance, our many volunteers, especially Zane Baker, Tom Downing, Dave Gulick, Chuck Barnes, and Rick Hartzell were priceless. No hawkwatch is successful without a loyal cadre of assistants – spotting birds, answering questions, and bringing food – so thanks to you all!
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The 2016 season total of 4,785 between March 15th and May 15th was our second highest total in the ten years of the project, and an impressive 17.6% above average (we exclude 2007 from our data analysis due to a change in methodology after this “trial” year).

Oddly enough, we amassed this tremendous total despite losing 16.5% of our possible coverage hours (9am to 5pm EDT) to weather, including fog, rain, snow, or high winds. The 414 total hours of observation was actually 6.6% below our average.

343 raptors passed the watch on April 17th, topped by the 980 tallied on 4/22 and 585 on 4/23. Those two amazing days changed our season dramatically – we went from worrying about a record low count to dreaming about a record high! 3,165 of our raptors passed through between April 16th and April 28th, accounting for 70% of our total flight.

Two rarities were recorded, headlined by a Black Vulture (our 7th of all time) on May 12th, and perhaps even rarer according to the season, a Broad-winged Hawk on March 20th (our previous earliest date was April 3rd, 2008 which itself was an outlier). We hypothesize that this was not a vanguard of the usual long-distant migrants arriving from Central America so early, but rather a bird that wintered either in South Florida or perhaps even well north of usual range thanks to the mild winter over the East.

Although southwesterly winds – our best conditions – were rare this spring, numerous days of west and light northwest in April, combined with sunny conditions and few weather systems during the peak weeks of our flight produced our great count, led by above average numbers of Osprey, Northern Harrier, Sharp-shinned Hawk, Broad-winged Hawk, American Kestrel, and Merlin. On our biggest day (4/22), light westerlies eventually turned to the southwest, and westerlies rotated around to the southeast on the following day.
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However, the mild winter and early onset of early spring – including snow-free conditions over much of the area on the first day of the count and ice-out already occurring on larger rivers – got the season off to a quick start, but also meant we missed a number of birds that had already continued north before the count started on March 15th. Below average numbers of Turkey Vulture, Bald Eagle, Cooper’s Hawk, Northern Goshawk, Red-shouldered Hawk, and especially Red-tailed Hawks were the result. “Locals” of each from Day 1 also affected our count as we had to err on the side of caution early on to not overcount local birds (especially vultures and eagles) every time they flew around the mountain. It was a very, very different season from the 2015 count, in which winter never seemed to want to go away.

However, our record low 1 Peregrine Falcon is not as easy to explain – perhaps the constant westerlies just kept this predominately more coastal migrant far enough towards the coastline of Casco Bay.

As always, we also keep track of non-raptor migrants to the best of our ability.
2,010 Double-crested Cormorants, 1457 Common Grackles, 1028 Canada Geese, 918 Tree Swallows, and 747 unidentified/mixed blackbirds led the way.

Sandhill Cranes are now an annual occurrence, and this year we tallied four birds: 2 on 3/26, and one each on 4/16 and 4/25. The expansion/colonization/recolonization of Maine by this magnificent species continues, and our hawkwatch is apparently well placed to sample their return flight. Other noteworthy migrants included a White-winged Crossbill on 3/17, migrant Bohemian Waxwings on 3/26 (50) and 4/19 (29) with numerous visits by small flocks to the Common Juniper at the summit, and two Blue-gray Gnatcatchers (4/22 and 5/3).

A total of 92 species were seen and/or heard from the summit, including regular vocalizations from local Barred Owls and a variety of warblers.

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  2016 Avg. 2008-2015 difference from average
Black Vulture 1 0.8 33.3%
Turkey Vulture 260 272.5 -4.6%
Osprey 513 431.1 19.0%
Bald Eagle 68 77.6 -12.4%
Northern Harrier 132 98.6 33.8%
Sharp-shinned Hawk 744 715.1 4.0%
Cooper’s Hawk 69 74.1 -6.9%
Northern Goshawk 2 7.9 -74.6%
Red-shouldered Hawk 75 91.4 -17.9%
Broad-winged Hawk 2123 1545.0 37.4%
Red-tailed Hawk 245 270.4 -9.4%
Rough-legged Hawk 0 0.9 -100.0%
Golden Eagle 0 0.5 -100.0%
American Kestrel 429 359.3 19.4%
Merlin 76 69.1 9.9%
Peregrine Falcon 1 5.4 -81.4%
       
Unidentified Raptor 47 47.3 -0.5%
Total 4785 4067.9 17.6%
       
Hours 414.25 443.5 -6.6%

Of course, this project doesn’t happen without your support of Freeport Wild Bird Supply, but we can’t do this without the support of Bradbury Mountain State Park and our co-sponsors, Leica Sport Optics. Our sincerest thank you goes out to Sunshine Hood, the new park manager at Bradbury (we can’t wait to grow the project with you!), and Jeff Bouton and Stan Bucklin of Leica.
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But most importantly, this project doesn’t happen without all of you joining our counter at the summit, learning about raptors, migration, and conservation. To show your support for the project, and to raise funds for future needs (counter’s salary, new signage, etc), check out the exclusive Bradbury Mountain Hawkwatch t-shirt by North Yarmouth’s Coyote Graphics. It features Michael’s original artwork of the view from Bradbury within the outline of raptor on the front, and raptor silhouettes by the 2016 Official Counter, Anna Stunkel on the back.

We look forward to seeing you at the summit again beginning on March 15th, 2017 – or perhaps sooner if weather conditions align (like more kite weather!)
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