Derby Hill conducted its annual hawk count this past spring from March 1st to May 31st. This is the 42nd consecutive season this full time count has been done, providing an invaluable source of data, which shows many interesting trends. In 2019, we counted a total of 82,684 raptors, which is the second best season ever at Derby, behind last year’s record count of over 101,000 raptors. The 2020 season saw a record number of Turkey Vultures and Bald Eagles, and the second best season ever for Broad-winged Hawks and Peregrine Falcons. Unfortunately, it was the worst season every for both Rough-legged Hawks and Northern Goshawks. The season began much differently than last year, with no ice on the lake and no snow on the ground in March, a continuation of a mild winter. But much of April and May was cooler than normal, especially the first half of May, with many days of NW winds, and as a result, the migration of many birds was delayed.
The total of 14,194 raptors in March was the second best March total ever. Overall the migration seemed to be a week o two ahead of last year’s schedule, with warmer temperatures and no snow on the ground. There was only one day lost to weather, when it snowed on the 23rd, but that light snow was gone by the next day. In fact, in many ways the weather seemed to be ahead of the birds, with man-days of south winds, but a lot fewer migrant raptors than expected.For example, by March 9th it was already 68 degrees F with strong south winds, but only 99 raptors were seen. Similarly, on March 20th it hit 71 degrees F with strong south winds, but only 296 raptors were seen. The last week of March was busy with raptors, including multiple days of over 1,000 birds. The highlight of the month was the huge Turkey Vulture flight on the morning of March 30th, when a record 5363 came over, mostly from 0900-1000 It was fun to watch the reports of this push of vultures as they moved through the region, with a count of 4588 at Presque Isle on March 29th, mostly in the morning from 1100-1200, and 4803 at Braddock Bay on March 29th, mostly in the evening from 1600-1800.
Much of April seemed cooler than March, with the vast majority days having North or West winds. Some birds continued to move despite the wind, especially the vultures, which don’t seem to mind what direction the wind is from. For example, the first two days of the month saw continued large fights of vultures, with both days over 3,000, despite a strong N wind. Even more interesting was that the main line of vultures on both days was over the North Lookout along the lake shore, rather than over the South Lookout was one would expect with the wind direction. The last three days of the month finally had SE winds, and the Broad-wings definitely took advantage of this. A very nice flight of 7680 Broad-wings came over on the 28th, most of which were kettling directly over the North Lookout in the morning until a lake breeze pushed the remainder of the flight to the south in the afternoon. The SE wind became very strong on the 29th and 30th, and it was interesting to see how the birds responded to this favorably gale- instead of being pushed up against the North Lookout, they became very spread out, with many birds like kestrels over the North Lookout, many more birds like Broad-wings over the South Lookout, and some birds even a mile or more to the south of the South Lookout.
Ordinarily one thinks of May as being warm and sunny with south winds and singing songbirds, but the first two weeks of the month were dominated by a very strong polar vortex that pushed record cold air into the region, and most days had a strong NW wind. There was even a major snowfall on May 9th! This was a very discouraging period to count, since it is often the peak of migration for many species, raptors and non-raptors alike. I think the totals of many later season species like Broad-wings, Sharp-shins, Merlins, and American Kestrels would have been substantially higher this year without this cold weather. Nevertheless, there were some highlights this month, especially at the very beginning and at the end. A flight of 13,204 adult Broad-wings on the 2nd was the third best count ever at Derby, The last week to ten days of the month seemed more May-like. My last day of counting on May 25th (Bill Purcell took over after the 25th) was a great grand finale for me, with a nice flight of 2589 immature Broad-wings, and record flight of 152 Bald Eagles, all counted while hiding in the shade of the big tree at the North Lookout.
Not surprisingly, a new seasonal record was set for Turkey Vultures again this year, with a total of 32,167 seen. An incredible flight of Turkey Vultures came through on the morning of March 30th, when 4291 were recorded in one hour, and 5363 were counted for the day, a new record. Counts of this species have steadily increased throughout Derby’s history, from less than 1000 prior to 1983. This increase has been most dramatic in the last ten years, with numbers nearly tripling It will be interesting to see how long this increase continues.
The count of 458 Osprey was about average, but noticeably less than the count of 595 last year. The peak was early, with 94 counted on April 29th. Local Ospreys were once again nesting on the cell tower at the South Lookout.
Perhaps as excepted, Bald Eagles set both daily and seasonal records again this spring. The season count of 1344 is nearly 100 birds more than last year’s record, and the count of 152 on May 25th beats out the count of 136 on May 6th last year. No doubt the count will be even higher next year.
The count of 448 harriers was about average, with a peak of 46 on April 13th.
Numbers of sharpies seemed below average, with only 2920 counted for the season, and the peak was only 448 on April 29th.
The season total of 285 Cooper’s was a bit better than last year, but still probably less than the overall average. The peak day was 26 on March 26th.
The dismal total of only four goshawks is the lowest ever in Derby’s history, lower than even five for the season in both 2016 and 2018.
The number of Red-shoulders substantially improved from last year, with a season count of 642 and a peak day of 103 on March 18th.
After last year’s record count of over 60,000, I figured this year would probably be more average, but with a season total of 40,929 in 2020, it ended up being the second best season ever at Derby. The peak was 13,204 Broad-wings on May 2nd, which is probably the 3rd best flight recorded here.
The Red-tail count of 2815 was very similar to last year, which means there’s still no sign of improvement from the recent low numbers. The peak day was 310 on March 27th.
The season count of 64 is the lowest ever at Derby, which is especially sad since this is the site’s signature species.
There was a drop in Golden Eagle numbers from last year, with only 38 counted this season. The lack of immature birds in late April and May was particularly noticeable.
The count of 470 kestrels was similar to last year, about average for recent years. The peak day was 122 on April 29th.
Although the count of 71 Merlins was below last year’s season, it was still above average. The peak day was 10 on April 30th.
The total of 28 Peregrines is the second best season at Derby, behind the count of 32 last season.
As with last year, I attempted to count all the non-raptors migrating through, which meant that I was out at sunrise nearly every morning. Overall the non-raptor migration was not quite as exciting compared to last year, although there were still a lot of birds. As with the raptor count, the persistent polar vortex in late April and the first two weeks of May really put a damper on the migration of many species that would normally peak at that time. Nevertheless, I counted a total of 788,414 individual birds of 185 species, which compares to 979,925 birds of 198 species last year, with nearly the same amount of effort put in (723 hours this year vs 753 last year). .As with last year, the vast majority of this total was geese and blackbirds, including 256,021 Snow Geese, 54,048 Canada Geese, 157,987 Common Grackles, and 167,828 Red-winged Blackbirds. There were also 18,902 American Robins and 15,387 American Crows, but gone were the hordes of Blue Jays that were seen last year. Only about 3,000 Blue Jays were seen this year compared to over 59,000 last year, a rather shocking difference,.Warbler migration was greatly delayed and then very short, lasting only about five days, with a peak of 19 species and 2118 Yellow-rumps on May 18th. There was a big swallow flight on April 30th included 2610 Barn Swallows, 1750 Tree Swallows, 46 Northern Rough-winged Swallows, 32 Cliff Swallows, and 9 Bank Swallows.. Since Rusty Blackbird is a species of special concern, it is worth mentioning that I counted 3380 for the season, including a peak day of 827 on April 29th; these numbers are similar to last year. Some of the other non-raptor highlights were three observations of Fish Crows on April 19th, May 14th, and May 21st, a single Surf Scoter on May 2nd, a Least Bittern calling on May 19th, and 2 Red-throated Loons on April 22nd during a large flight of 106 Common Loons. These were all species that I did not see last year.
I greatly enjoyed my second season at Derby Hill, a very relaxing and comfortable place to count birds and to witness visible migration. I would like to thank Dave Fitch for making it all possible and for keep the cottage in such great shape. I would also like to thank all the wonderful people who showed up to watch migration, help spot birds, and even bring treats, both for me and for the birds: Joe Brin, Matt Brown, Ron Burdick, Peter Davidson, Liz DelConte, Dave Fitch, Kevin McGann, Don Metzger, Bill Purcell, Chris Reynolds, Andy Saunders, Paul Shanahan, Judy Thurber and Drew Weber were all regulars, though of course there were lots of other folks who came to visit as well. Finally, I would like to give a special thanks to Bill Purcell for doing the last six days of the count, which was a big help to me. I hope to see everyone next year.