Niagara Peninsula Hawkwatch

 
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2010 MIGRATION SUMMARY

By John Stevens

Average, typical, so-so and concentrated are some of the terms that could be applied to the 2010 migration at Beamer Memorial Conservation Area (Beamer) atop the Niagara Escarpment in Grimsby, Ontario. Of course within that average year are several atypical observations, many of which were determined by weather conditions.

For the second year in succession, the season was virtually free of any snowfall (0.2 cm or about 1% of normal) but at least at the beginning of March there was some snow cover. That had all melted by March 10th so except for the early Red-shouldered Hawk on February 28, we were denied the pleasure of seeing this species with under lighting this year as their migration didn’t start in earnest until March 16. The absence of snow did not mean there wasn’t precipitation as four days in March were totally wiped out and five other days in the month were partly affected by rain. In general the temperatures were above normal during March but the migration was very slow until the 16th with the only really good day occurring on the 31st when 1,077 raptors were counted. That helped the total count for the month to be a respectable 3,925.

April 2010 was very warm, particularly at the beginning of the month, with the mean daily temperature being 4.4 degrees above normal. This produced the seventh best April count since full coverage began in 1981, 10,736 birds. Over half of this total passed during the first four days with the April 1 total of 2,049 being the greatest daily count of the season. There were also two days in April of inclement weather with no flight recorded.

For the third year in a row, the May count of 511 was very low with only May 1 and May 3 having more than 100 birds. Only 12 days received any coverage in May, partly because poor weather wiped out two days but the hours counted was particularly low as rain curtailed activities on five other days. It is becoming increasingly difficult to find counters in May, especially those willing to put in a full day when movement can occur from early morning to late afternoon. Overall, May was also above normal in temperature although not particularly during the first half when we provide coverage and half of those days had precipitation.

The season’s total count of 15,175 birds of 16 species was about a thousand above the 30-year average but slightly below the most recent 5-year average of 15,404. The 518 hours of records in 2010 represents about an average of recent years despite the low total in May. It is somewhat less than the 30-year average because of the first eight years when coverage extended to the end of May. The total hours was helped by many days in March and April with extensive coverage when Barry Cherriere stayed for an hour or two after the assigned counter left.

Species Highlights

Both Turkey Vultures and Peregrine Falcons set new annual count records this year while the Merlin count of 22 tied their previous high that was first set in 1996 and matched in 2000. The Turkey Vulture total of 6,732 was 10% above the previous record from 2008 and continues the steady upward trend in their numbers that has been ongoing since full-season counting began at Beamer in 1980. In 31 years, on only two occasions have we had to wait more than one year for the Turkey Vulture count to set an annual record. The two exceptions were the periods following 1988 and 1994, years when the counts had very large increases that took six and four years, respectively, to be matched.

The Peregrine Falcon has only ever been seen infrequently at Beamer. The resident population increase that has occurred in Ontario for this species since the recovery program, instituted after the ban on chlorinated pesticides was imposed, never resulted in a significant increase in their counts at Beamer. As recently as 2007, only 2 were recorded in the entire season. This year’s total of 12 was 33% above the previous high count of 9 set in 2006. We can hope that this signals the start of a greater flight at our watch site of this exciting bird although it is possible that a nearby resident was being observed repeatedly this year.

Goodrich and Smith in State of North America’s Birds of Prey (2008) state that “Black Vultures are expanding their range in Eastern North America”. We had seen single birds in 1992, 2000, 2004 and 2008. This year counter Tom Thomas recorded Black Vultures on separate days over a month apart. One bird was moving westward, the normal route at Beamer, while the second went eastward, a direction more often seen near the end of the migration period. It is possible that the same bird was seen twice but it seems unlikely. At Braddock Bay, located less than 200 km to the east at a similar latitude to Beamer, 11 Black Vultures were recorded in 2010 compared to the usual average of one. It appears that the range expansion may be reaching the southern shores of Lake Ontario.

Two other positive findings were made in 2010. The Osprey count at 53 birds rebounded from last year’s below average total of 39 and was the best count in four years although still well below the seasonal record of 71. The Bald Eagle total of 64 was below the recent 5-year average of 70 but is double the long-term average and was the sixth highest count for the species at Beamer.

The findings for most of the remainder of the fifteen species that are regularly seen at Beamer were below average. All the Buteo species had markedly lower counts in 2010 compared to 2009. In more perspective, Red-shouldered Hawks were 33% below, Broad-winged Hawks were 17% below and Red-tailed Hawks were 23% below their respective 30-year averages. A dark morph Broad-winged Hawk was seen on April 13th.

The 29 Rough-legged Hawks counted represents the second lowest count that we’ve ever had for this somewhat irregular migrant, and is 63% below the 30-year average and 67% below the recent 5-year average. The count for this species last fall at Cranberry Marsh on the northern shore of Lake Ontario was also relatively low so perhaps the low Beamer total in 2010 was to be expected.

Moving to the Accipiters, the 2010 results somewhat mixed with the Sharp-shinned Hawk count 24% above the recent 5-year average although still well below the 30-year average. In contrast, the Cooper’s Hawk total was just 125 birds representing the third lowest count since 1980 and 26% below the recent 5-year average. It is possible that the counters are becoming more experienced at identifying the local Coops and they are not being tallied as they may have been previously.

The Goshawk count of 8 was typical of a non-irruption year but somewhat surprising in light of the higher counts last fall at watches on the northern shore of Lakes Erie and Ontario. Most of those that passed the site this year seemed to be quite accommodating by allowing the counters excellent views to confirm their identity.

The Golden Eagle count was on the 30-year average but below the most recent 5-year average. We have had several years with greater numbers of this species recently and this total marks a return to a more characteristic number.

The average number of Northern Harriers seen in a year at Beamer is 141 but significant variation occurs from year to year with little in the way of trends being evident. In 2010, the count was only 109, the eighth lowest total on record. This is below the recent 5-year average by 14%.

The American Kestrel count was below both the recent 5-year and long term (30-year) averages and at 55 birds was less than half the 120 seen in 2008. This was the second lowest total for this species that we’ve had over the 31 years of full season coverage, greater only than the 45 birds seen in 2005. A widespread decline in the population of American Kestrels in the northeast has been detected during the RPI analyses for fall watch sites and, except for 2008, the springtime observations at Beamer appear to confirm this trend.

Lucky Tom Thomas was also the counter on April 11 when 13 species were counted, missing only Northern Goshawk and Peregrine from our 15 regular migrants. No other day had more than 11 species. Finally, it should be noted that if next season has slightly more birds than this year, some time near the middle of May 2011 we should record the 500,000th raptor since the watch started in 1975.

Thanks go to the following volunteers for accepting responsibility as designated counters: Bouwe Bergsma, Peter Booker, Barry Cherriere, Bob Curry, Geoff Carpentier, Ed Couture, Sandy Darling, Keith Dieroff, Chris Escott, Tim Foran, Sandra Horvath, Marcie Jacklin, Bruce McKenzie, George Naylor, Bill Smith, Janet Snaith, John Stevens, Mike Street, Tom Thomas, Phil Waggett and Rob Waldhuber. Thanks also to the numerous observers who put in lots of time assisting. These include Don Peuramaki, Cody Law, Colin Horstead, Mike Kirchin, Linda Cherriere, Dave Sked, John Niewiadomski, Gord McNulty, Dave Weare, Toni Carson, Brian Hawthorn, Doris Southwell, Eric Single, George Holland plus several others, many of whom come from a great distance and appear occasionally.

2010 NIAGARA PENINSULA HAWKWATCH MONTHLY COUNTS

SPECIES
FEB
MAR
APR
MAY
TOTAL
Black Vulture
0
1
1
0
2
Turkey Vulture
0
1983
4659
90
6732
Osprey
0
0
50
3
53
Mississippi Kite
0
0
0
0
0
Bald Eagle
0
34
26
4
64
Northern Harrier
0
24
81
4
109
Sharp-shinned Hawk
0
178
1893
268
2339
Cooper's Hawk
0
71
49
5
125
Northern Goshawk
0
7
0
1
8
Red-shouldered Hawk
1
403
107
2
513
Broad-winged Hawk
0
0
2858
64
2156
Swainson's Hawk
0
0
0
0
0
Red-tailed Hawk
2
1172
929
53
2156
Ferruginous Hawk
0
0
0
0
0
Rough-legged Hawk
0
17
10
2
29
Golden Eagle
0
5
3
0
8
American Kestrel
0
5
44
6
55
Merlin
0
7
10
5
22
Peregrine Falcon
0
7
3
2
12
Gyrfalcon
0
0
0
0
0
Prairie Falcon
0
0
0
0
0
Unidentified Accipiter
0
3
0
0
3
Unidentified Buteo
0
5
5
1
11
Unidentified Eagle
0
0
0
0
0
Unidentified Falcon
0
0
2
0
2
Unidentified Raptor
0
3
6
1
10
Total Raptors
3
3925
10736
511
15175
Hour Counted
4.3
206.9
229.9
77.3
518.4
Raptors/Hour
0.7
19.0
46.7
6.6
29.3
 
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