> On Apr 28, 2024, at 1:04 PM, David Brandes <000016035b42742c-dmarc-request...> wrote:
>
> Fantastic report, Nick! so grateful to you and Jon for keeping this important site running all these years, and to Andrew for continuing the tradition of counting excellence!
>
> Dave Brandes
>
> On Saturday, April 27, 2024 at 04:43:04 PM EDT, Nick Bolgiano <nickbolgiano...> wrote:
>
>
> 2024 was the 24th full season of the spring hawk watch at Tussey Mt, staffed daily Feb 20-Apr 26. The watch site is located on the top of Tussey Mt, the second ridge from the north and west in the western Ridge-and-Valley physiographic province and near the boundary between Huntingdon and Centre counties. The watch’s primary focus is monitoring the spring Golden Eagle migration. This report reflects that focus.
>
> Annual Golden Eagle totals at western sites such as Bridger Mts, MT; Mt Lorette, AB; and Gunsight Mt, AK, are commonly around 1,000-2,000. However, they draw from a western population of approximately 60,000 birds. The eastern Golden Eagle population is thought to have about 4,000-5,000 birds. Among eastern watch sites, the Golden Eagle total at Tussey Mt ranks second to Mackinac Straits, MI, in the spring, while Bald Eagle Mt ranks first in the fall (Table 1). No other spring site east of Michigan consistently counts close to the number of Golden Eagles that we do at Tussey Mt, although the 2024 total at the Allegheny Front site was close. Thus, these local hawk watches are important in monitoring the eastern population.
>
> Table 1. 10-Year Golden Eagle Averages (2014-2023) at Some Eastern North American Watch Sites.
>
> Spring
> Fall
> Site
> 10-year average
> Site
> 10-year average
> Tussey Mt, PA
> 169
> Bald Eagle Mt, PA #
> 324
> Allegheny Front, PA
> 80
> Allegheny Front, PA
> 208
> Derby Hill, NY
> 55
> Franklin Mt, NY
> 178
> Braddock Bay, NY
> 27
> Stone Mt, PA
> 150
> Mackinac Straits, MI
> 231
> Jacks Mt, PA
> 128
> West Skyline, MN *
> 155
> Waggoner’s Gap, PA
> 215
>
>
> Hawk Mt, PA
> 123
>
>
> Detroit River, MI
> 82
>
>
> Holiday Beach, ON
> 59
>
>
> Hawk Ridge, MN
> 195
> * - 6-year average for West Skyline; # - 4-year average for Bald Eagle Mt
>
> The 2024 official counter was Andrew Bechdel, who returned for a second year. Andrew did an excellent job; he was very diligent and his increased raptor ID skills were apparent. He joints a cohort of distinguished local birders who have been hawk watch counters at Tussey Mt: Jon Kauffman in 2009-2010 and 2014, Lewis Grove in 2017, and Sean McLaughlin in 2021 (Sean has subsequently counted raptors in Duluth, MN, at the West Skyline site in the spring and the Hawk Ridge site in the fall).
>
> The 2024 watch was conducted on 56 days, with 414 hours of watching. This closely matches past median (middle) effort of 56 days and 403 hours. We accomplished our primary goal of conducting the watch over the same time span as previous years and with similar hours and watchfulness. Season totals are shown in Table 2.
>
> Table 2. 2024 season totals and 10-year averages (2014-2023).
>
> Species
> 2024
> 10-year average
> 2024 Ranking
> Turkey Vulture
> 196
> 186
> average
> Osprey
> 59
> 89
> below average
> Bald Eagle
> 69
> 69
> average
> Northern Harrier
> 19
> 21
> average
> Sharp-shinned Hawk
> 203
> 162
> above average
> Cooper’s Hawk
> 28
> 26
> average
> American Goshawk
> 0
> 1
>
> Red-shouldered Hawk
> 35
> 40
> average
> Broad-winged Hawk
> 1378
> 920
> above average
> Red-tailed Hawk
> 213
> 286
> below average
> Rough-legged Hawk
> 0
> 2
>
> Golden Eagle
> 164
> 169
> average
> American Kestrel
> 38
> 42
> average
> Merlin
> 4
> 6
> average
> Peregrine Falcon
> 4
> 3
> average
> Total
> 2425
> 2020
>
>
> Below-average counts were observed for Osprey and Red-tailed Hawk, but these observations were consistent with long-term trends. Ospreys in Northeastern North America have been experiencing a decline, possibly related to the rise of Bald Eagles, and there is evidence that Red-tailed Hawks are not migrating as much as their ancestors did. Above-average counts were observed for Sharp-shinned Hawk and Broad-winged Hawk. The Sharp-shinned Hawk count was the highest since 2104 and was somewhat surprising since we had observed low Sharp-shinned Hawk totals during the previous fall. The 1378 Broad-winged Hawks was our 4th highest season total; 83% were observed during a four-day period, Apr 15-18. All other raptor species were observed in average numbers.
>
> The 24-year trend in Golden Eagle total count has an overall hill shape, with lower counts during 2001-2007 (average 161), higher counts during 2008-2015 (average 205), and lower counts again in 2016-2024 (average 153). The 2024 total of 164 was just below the 10-year average of 169 and welcome after 2023’s low count of 118 (Figure 1). I suspect that lower totals occur when less severe winters cause Golden Eagles to winter farther north than they previously did or allow them to begin filtering back north before the spring migration begins in earnest during late February and early March. Sometimes, as in 2023, a sustained W/NW wind regime in the first half of March seems to limit Golden Eagle counts, but the 2024 wind regime was much more favorable during the peak Golden Eagle migration period.
>
> The first detections of migrating Golden Eagles at Tussey Mt have been fairly consistent across seasons, so there is no indication that many have moved past us before we start (the Allegheny Front watch starts earlier than we do and they have only detected a few before we start). In 2024, we recorded the first three Golden Eagles on Feb 21 and the first significant count, nine, on Feb 26. They then came with a rush in early March, with 95 counted during the first 12 days (which includes four rain days), 58% of the season’s total. The high count was 27 on Mar 8. The cumulative Golden Eagle chart shows that the 2024 count was slightly ahead of the long-term average through Mar 16, but from mid-March on, the detection pattern was very similar to the observations of other years (Figure 2).
>
> The best winds at Tussey Mt are from the S or SE, which we observed on Feb 26-27 and Mar 1, 3,4, 8, and 11-12. This largely explains the early Golden Eagle movement. At the Allegheny Front hawk watch, on the Allegheny Front west of Bedford and about 61 air miles to our southwest, favorable flights occur when winds are from the E or SE. The Allegheny Front site experienced their best Golden Eagle count this season and it was concentrated during the same time period as the good flights at Tussey Mt (Figure 3). Interestingly, the Derby Hill, NY, site, near the SE end of Lake Ontario, also has experienced one of their best Golden Eagle seasons (Figure 4).
>
> I suspect that when a sustained period of S or SE winds occurs during the peak period, as happened this year, a large percentage of Golden Eagles moves north along the Allegheny Front and Laurel Ridge to its west and we miss seeing those birds. I have noticed before that sustained S or SE winds seem to push many Golden Eagles toward the Allegheny Front and, at Tussey Mt, I theorize that we need periods of both S/SE and W/NW to keep them on our ridge. While Tussey Mt has many of its best flights on S/SE winds, we also see Golden Eagles on W/NW winds. Tussey Mt is not situated along a landscape feature that is commonly called a “leading line”, like at the Great Lakes sites, or acts as a natural “collector” of Golden Eagles, like Bald Eagle Mt does in the fall. Instead, we benefit from the length of our ridge, which extends south into Maryland, and its location in the western Ridge & Valley.
>
> The shapes of the three cumulative curves help to tell a story about the three sites. Counts at Tussey Mt have been more consistent, which I believe is related to the many Golden Eagles moving through here and the consistency of our effort over the years. Counts at Allegheny Front have been more variable largely because of that site’s strong dependency on E and SE winds. Derby Hill observations are dominated by immature birds, as shown by consistent flights occurring in April. However, as in 2024 and 2021, they sometimes see many Golden Eagles in March, probably related to more adult Golden Eagles being seen there when winds have been from the S or SE.
>
> Thanks to our sponsors, Shaver’s Creek Environmental Center, the State College Bird Club, and individuals. Also, thanks to the many people who visited and helped to spot migrating raptors; we appreciate all the good help. Next year will be our 25th season, a good milestone to achieve.
>
> Nick Bolgiano
>
