By David Wheeler, Derby Hill Bird Observatory Hawk Counter, Spring 2016
Season Overview
From 1 March to 31 May 2016, 42,924 migrant raptors of 17 species were noted during 565 hours of observing from the north and south Lookouts at Derby Hill Bird Observatory near Mexico, NY, Oswego County. Rarities included 2 Black Vultures and the first Swainson’s Hawk since 2012. An excellent late-May push of Bald Eagles and immature Broad-wings occurred, having been missed in 2015.
Monthly Review
March
Winter 2015-2016 was mild in northeastern North America, both in snowfall and temperature. The count began with bare ground (compare March 2015!) and most of March continued the mild trend. Raptor-arrival milestones were 7-10 days ahead of the previous season. Lake Ontario was entirely open and no floating ice was seen from the watch site (again, compare March 2015). Numbers of the early migrating species like Cooper’s Hawk, Red-shouldered Hawk, Golden Eagle, Rough-legged Hawk, and Red-tailed Hawk were disappointing, prompting speculation that the mild winter had not necessitated as much southward movement of these hardy birds. Observers shifted their anticipation to April, hoping for more of these popular raptors.
In March, 9,750 raptors of 15 species were counted in 157.5 hours of coverage.
April
After a mild March, the first ten days of April saw a return to winter-like conditions with cold NW wind and several days with snow covering the lookout. High pressure took control for the second half of the month, giving day after day of sun and northeast wind (normally an uncommon wind for the site). Good flight days were unpredictable and coincided with raptor supply more than concepts of good flight weather.
Normally Derby Hill’s biggest month, April numbers were a big disappointment and there were few counts at the North Lookout. Many birds were undoubtedly missed flying inland beyond vision, but Derby Hill protocol does not allow the official count to “chase” the flight line. Days with obvious movement lacked the hoped-for Rough-legs and other fan-favorites, dashing the spirits of observers and guaranteeing record-low counts of some species.
In April, 17,392 raptors of 16 species were counted in 200.5 hours of coverage. This is slightly more than half the number for April 2015.
May
Late-April’s northeast-wind situation spilled mercilessly into May. Most days started with light southeast wind, which quickly gave way to Lake breeze. Birds got through anyway, as they did in the prior months and for eons before. While 2015 never enjoyed a late-May flight of “Florida” Bald Eagles and immature Broad-wings, 2016 brought two excellent flight days in the final week that bolstered the season’s count.
In May, 15,782 raptors of 15 species were counted in 207 hours of coverage.
Species Accounts
Black Vulture
2016 was another typical but disappointing year for Black Vultures, with one bird on 27 March and another on 1 April and none after that. Observers and counter alike eagerly await a time when good numbers of this handsome vulture will be mixed in with its more common cohort.
Turkey Vulture
Though almost 4,000 birds off the preceding two years of record counts, 18,301 is still a big jump from 2013. One can only speculate whether another record-high might have been realized if not for our mild winter and unfavorable early-April weather. First bird was noted on 6 March and the peak flight was 2,233 on 27 March, only about half the peaks of 2014 & 2015. A great hour on 7 April produced 1,200 birds passing low over the North Lookout. As with most years, several were observed with no tail feathers and another with a few white primaries.
Osprey
Spring 2016 gave us 316 Ospreys, 180 birds shy of the recent 10-year average and the lowest since 2010. The first bird arrived on 24 March and peaked with 41 birds on 3 May. In the last ten years, Osprey numbers have fluctuated between 300-700 birds. The presence of local birds along Lake Ontario may also affect the count some years more than others, while this season’s unfavorable winds may have caused birds to be missed inland. In May, an Osprey was observed daily from the South Lookout dragging long sticks to the top of the (very high) cell tower visible in the back sky. Will it be successful?
Bald Eagle
439 Bald Eagles were officially counted passing Derby Hill, about average for the last 10 years but substantially below some. Post-breeding adult and juvenile (this year’s hatches) “Florida” Bald Eagles made a strong showing in late May with 112 passing in three days beginning on the 26th. Like Osprey, BE numbers in the last ten years show substantial variation. 2014’s May count of 456 surpasses 2016’s entire season. It is worth noting the difficulty in counting BE as some repeatedly cruise the Lakeshore.
Northern Harrier
In 2016, a total of 409 Northern Harriers were counted, substantially below the recent 10-year average of 507. As with other species, considerable variation in annual counts is noted. Counting this season was especially difficult due to the many South Lookout watch days. Harriers were often seen cruising up Sage Creek or crossing the road and immediately heading for the “ditch” to hunt. To count or not to count, that was the question. The mild winter may have also allowed more of these fan-favorites to remain north of the watch site. A great flight on 7 April produced 95 birds, 52 of which passed in a single hour.
Sharp-shinned Hawk
With only 2,031 counted, 2016’s Sharp-shinned Hawk total is nearly a thousand birds shy of the recent 10-year average. Best counts were only half what might be expected. Sharpies however are the most likely to be missed during long periods of South Lookout counting such as were experienced this season. The species is prone to flying low and close to Lake Ontario even on N or NE wind and these birds won’t be above the treeline and thus not visible from inland. Derby Hill’s protocol does not allow combining counts from separate observers at the two lookouts. Our smallest accipiter is often seen spiraling with larger hawks, usually at the top of the group where it is on the “safe” side of the bigger birds, but sometimes low at the bottom where it is close to the safety of dense cover.
Sharp-shinned’s are of substantial conservation concern because of plummeting numbers thought to be related to a decline in songbird populations throughout its range. Small passerines are this woodland accipiter’s primary food source.
Cooper’s Hawk
Cooper’s Hawks numbered 166 this spring, much below the recent 10-year average of 321. The species is common in winter at the site latitude and may simply not have come as far south because of the preceding mild winter. Much water remained open and thus small ducks and other likely prey species were never forced out. Derby Hill has had for many years a “local” Cooper’s seen display-flapping along the west horizon. This bird was often flying high arcs on deep wingbeats and seen escorting other Cooper’s out of its airspace.
Northern Goshawk
Only 5 Northern Goshawks were seen passing Derby Hill this season, with no certain adults. The species is irruptive however and the winter was mild, thus a strong candidate for poor showing. Still this is the second season in a row with very low counts. Two of the five perched in a tree near the North Lookout before moving on. This is very unusual as raptors rarely stop at the site.
Red-shouldered Hawk
The Red-shouldered Hawk count for 2016 was 340, substantially below the recent 10-year average of 455 and a drop in the proverbial bucket compared to historical counts at the site. Its status as a candidate to remain to our north in mild winters is open for debate, but this may be a factor. First bird arrived on 6 March and peaks of 50 and 68 occurred on the 12th and 17th of March (nearly two weeks earlier than the peak dates for 2015). Immatures quickly took over with the first noted on 26 March and all but 2 of 16 were young birds by the 30th.
Broad-winged Hawk
First Broad-wingeds of the 2016 season were noted on 15 April, with triple-digit counts following soon after. Best days gave us 3,427 birds on 27 April, 4,244 on 3 May, and 2,129 on 4 May. This good showing was further improved by a nice late-May flight of immatures – 1,665 on the 26th and 1,127 on the 27th. One is left to wonder what the count might have been had winds been more favorable during the peak period, since the species is prone to being blown inland during South Lookout flights. The season finished above average with 18,392 birds compared to 16,513 for the recent 10-years.
Given the strong late-May burst of young birds seen at both Derby Hill and Braddock Bay, birds may well be seen throughout the summer on favorable winds.
Red-tailed Hawk
Spring 2016 saw only 2,140 Red-tailed Hawks counted passing Derby Hill, barely half the 10-year average of 4,197 and by far the lowest count since standardized recording began at the site in 1979. First birds were on 4 March with four triple-digit days in the second half of the month. Peak flights were only half what is expected from recent history – best was 223 on 27 March. However, the species massive range north of the watch site and hardy, adaptable nature make it a strong candidate to remain north in mild winters. Unfavorable winds at the watch site, especially during early April, almost certainly caused some birds to pass far inland. Soaring birds such as the buteos are especially prone to this fate during north wind. For the first time in several years, no unusual subspecies, dark-morphs, or leucistic Red-tails were seen. A local Red-tail near the South Lookout was persistently badgered by an American Crow nesting nearby and often seen holding its own territory from the branch of a nearby tree. A second Red-tail pair that nests southeast of the lookout could also be seen. This is an interesting scenario in as far as one could not normally observe adjacent Red-tail territories at the same time.
Rough-legged Hawk
This spring, only 65 Rough-leggeds were counted passing Derby Hill, less than a third of the recent 10-year average of 219 and by far the lowest since standardized recording began in 1979. The count site is at the southern end of the species winter range and it is also irruptive and not known for traveling any farther south than necessary. Following a mild winter, poor counts are expected. Some may even have gone through in February, as reflected in the (very early) peak flight date of 9 March (vs. 2 April in 2015). The last bird was seen on 18 April.
Of the 45 that were seen well enough to reliably determine plumage, 64% were light and 36% were dark (a higher fraction of dark than the 20-25% often cited as typical). A fan-favorite and Derby Hill’s signature bird, its arrival will be eagerly awaited next season.
Swainson’s Hawk
A light-morph bird passed the watch site on 26 May during a substantial flight of immature Broad-wingeds and Bald Eagles. The bird had been seen the previous day flying by Braddock Bay, recognized in photos by Braddock counter Ryan MacLean as the same bird by its missing central tail feathers. A second Swainson’s thought to be a dark bird had also passed the previous day but was missed at Derby Hill. This year’s bird was the first since 2012 but the species is a strong candidate to be missed. Best days for it usually coincide with southwest wind, the best wind at Braddock Bay, but a wind which causes birds to “cut the corner” and fly very high and far out over the Lake at Derby Hill.
Golden Eagle
The 24 Golden Eagles that passed Derby Hill this year is much below normal for modern times – 61 is the recent 10-year average. The first two birds arrived on 9 March but February migration is also possible for the species. The entire April count was only 1/3 of the best April day of 2015. Thankfully the species was seen a few times in early May. It is a candidate for remaining north in unusually mild winters, so hopefully numbers will rebound next season. In referring to these low counts of hardy species, long-time hawk watcher Gerry Smith observed “this is what happens after a wimpy winter.”
American Kestrel
The 2016 season produced only 179 Kestrels, much below last year’s total and the recent 10-year average of 327. As with other species, substantial variation exists year-to-year with similar low numbers in both 2010 and 2012 but 677 birds in 2013. Our smallest falcon is known to be in decline, but what causes these up and down counts over relatively short time periods? Obviously some winter at the site latitude and thus might reasonably be a candidate to remain farther north in mild years and thus not available to pass and be counted. Additionally, “new” birds were often difficult to tell from a local pair that nests nearby. Peak count on 7 April was only 24 birds, barely a third of that tallied on the best day in 2015.
Merlin
Increasingly common at the site latitude in winter, 2016 saw only 36 pass. This is slightly more than half that of 2015 and 13 off the recent 10-year average. First birds were on 9 March and scattered throughout the count period with a good showing in early May. 30 April gave observers at the South Lookout a very unusual sight – a soaring Merlin! The bird, an adult female, was spiraling with a male Kestrel which was making sure to stay above the larger falcon. Eventually both glided out and gave great looks passing over the watch site.
Peregrine Falcon
First 3 birds were on 9 March, a very early date especially for more than one and likely reflecting the amount of open water and diving ducks available as prey the previous winter. 14 total were scattered throughout the count period, equaling the recent 10-year average, but much fewer than the 51 seen at Braddock Bay this season. Adults passing in early May were likely the northern-nesting tundrius subspecies, and Peregrines generally may just as easily overfly the Lake as travel along its shoreline. Several soared cooperatively for long periods, providing good views of the species’ characteristic “bow and arrow” shape.
Non-raptor highlights
Songbirds, waterfowl, and other visible non-raptor migration was followed as time and weather allowed. Short-distance migrants that winter in North America dominate in March, with long-distance neotropical migrants arriving in late April and May.
Snow Goose – Flights ramped up quickly to daily peaks in the 10,000-15,000 bird range on March 7 and 8, and were mostly done by March 15. Compared to 2015, peak dates occurred three weeks earlier and this year’s flight was mostly over before the first bird of last year! Few if any “test” migrations were observed where birds went back. Unlike Canada Geese which often overfly water, our Snow Geese are seen as loose, overlapping V-formations making a 90 degree turn on the west horizon to follow the Lakeshore.
Ross’s Goose – Two were seen on March 7 and one on March 24 mixed in with Snow Geese.
Herons – 20 Great Blue Herons and a Great Egret passed on April 7, plus 2 more Egrets on April 22. American and Least Bittern were heard in Sage Creek Marsh throughout May. One of our neighbors stopped to report a Black-crowned Night Heron in Sage Creek south of Rte 104B on April 23. The species is always scarce in the vicinity of the watch site.
Sandhill Crane – 13 total for the season, the first four on March 17 (three weeks earlier than 2015), then scattered throughout late-April. Max group was five on April 21.
Shorebirds – First Killdeer arrived on March 7 to find open ground and much better weather than last year. Common Snipe, Solitary Sandpiper, Lesser Yellowlegs, American Woodcock, and an Upland Sandpiper rounded out a very unexceptional season.
Gulls & Terns – Mild winter translated to a poor spring season as most seemed to have migrated early. Black Tern was missed altogether.
Short-eared Owl – By far the most likely owl to be seen migrating by day, this bird soared and was blown about in high winds on April 29 south of the south lookout.
Common Nighthawk – 450 were counted on May 26, an excellent single-day number but likely a typical season count compressed into one four-hour period by the effects of weather. A single bird passed the south lookout at high noon on May 20.
Northern Flicker – Certainly one of our most attractive flyby species, mid-April saw numerous triple-digit flights. Best day was April 17 with 500+ birds.
Flycatchers – First Eastern Phoebe was noted on March 25. An Olive-sided Flycatcher was seen near the south lookout on May 26.
Northern Shrike – Seen many years especially at the South Lookout, but not this year.
Blue Jay – Obvious northbound migration began in late April with peak flights of 2,000-2,500 birds on May 12, 14, and 26.
American Crow – Good flights in March included 4,500 on the 7th and 8,000 on the 8th.
Tree Swallow – First birds on March 13 and 30 on the 24th.
Common Raven – Much scarcer just 10 years ago, ravens were seen or heard most days during the count period.
Black-capped Chickadee – Unfortunately, no substantial movements were noted.
Winter Wren – seen along Sage Creek Rd on the early date of March 24, the bird likely wintered nearby.
Eastern Bluebird – As in previous years, some small flocks were noted in late May.
American Robin – Best flights were 1,500 – 2,000 birds on several days in the second half of March.
Cedar Waxwing – 500-1,000 birds on peak days in late May.
Warblers – May morning flights were dominated by American Redstart, Yellow, and Yellow-rump. Prairie and Golden-winged Warbler delighted visitors on May 12, while a male Hooded Warbler was photographed during morning flight on the 17th. A nester on the southern Lake Ontario shore, Hooded is scarce north of the watch site.
Sparrows – Multiple Vesper Sparrows graced the south lookout in April, while a non-singing Clay-colored was found on the bluff on May 21 (female?). A Chipping Sparrow was seen near the cottage throughout May singing a Clay-colored-like sequence of trills. Apparently the song has been previously documented in the species and included in the Sibley Guide smartphone app as “dawn song,” though the Derby bird sang it constantly all day. In reality the pacing and tone quality were not quite right for Clay-colored. The bird was never heard singing the familiar long, single trill. A Henslow’s Sparrow flight call was picked up by the night-flight microphone just after midnight on June 2. It was the first in five years of monitoring.
Blackbirds, etc – These conspicuously low-flying morning and evening migrants were on the move from the beginning of the count period. March 7 delivered 12,500 Red-wings and 122 Grackles, awesome numbers for the date. Surprisingly, 10,000 icterids were still noted on April 15. First Eastern Meadowlarks on March 13. Baltimore Orioles put on a good show in morning flight. Only two Orchard Orioles were noted.
Winter Irruptives – Not a great winter and thus not a great spring, but Pine Siskins were well represented. No Red-breasted Nuthatches or Evening Grosbeaks were detected, and only a light movement of Purple Finches.
Acknowledgments
Thanks to Bill Purcell and Phil Taylor who provided coverage on days off. They often kept count from the south lookout while I was moving the official watch headquarters. Bill also helped update the running-total white board (generously donated by Tom Carrolan) at the north lookout kiosk. Braddock Bay hawk counter Ryan MacLean texted rarities and flight status from our nearest neighboring hawk watch. Many observers pointed out birds: Chris and Sally Holt, Phil Taylor, Pete Davidson, Jim Tarolli, Wayne Fidler, Mary and Mark Magistro, Jeff and Theresa Covington, Judy Thurber, Jay and Pat Chapman, Judy Wright, Ken Burdick, Kevin McGann, Joe Carey, Ron Burdick, Brian Miller, Andy Francis, and many others are greatly appreciated. We continued to enjoy visitors from hawk watches throughout Pennsylvania and New England. Mike Tetlow provided spotting help during our big late-May flight and was diligently on the lookout for rarities. Gerry Smith kept watch early in the morning and provided historical perspective, and with Dave Fitch managed the site. Tom Riley did a diligent job of updating the Derby Hill Facebook page with daily count reports. Alison Kocek got the word out on Twitter about late-developing hawk flights. Jason Sodergren of HMANA provided help uploading hourly count data to the Hawkcount.org website. Bill Evans continued his night migration monitoring and daily breakdown of flight calls recorded by the Derby Hill microphone. Steve Kolbe provided moral support. The entire Birdfest committee & volunteers, led by Maryanne Adams, is highly commended for pulling off another successful event. Ken Hodgson continues to maintain the grounds and keep the trails and lookouts in excellent condition. Diane Emord maintained our Bluebird/Tree Swallow boxes and installed a sign denoting our newly-acquired status as a Monarch Waystation. Ken and Rose Burdick facilitated the Birdathon compilation picnic. Judy Thurber maintained the Fritz Scheider garden and kept our suet feeders full. Many of our regular visitors contributed sunflower seed. A huge thanks to all and apologies in advance to anyone I may have missed.
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