Niagara Peninsula Hawkwatch

 
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2013 MIGRATION SUMMARY

 

The last couple of seasons at Beamer, we have been able to celebrate the apparent arrival of Black Vultures as our sixteenth regular species (2012) and a record count of migrants (2011). In 2013 by contrast, it is going to be difficult to find much to celebrate at all. The final tally showed 12,209 birds of fifteen species, the lowest total since the 11,665 birds in 2000 and 16% below the long term (32-year) average (see Table 1). However that really doesn’t reflect how poor the count was this year.

 

For the first time, and hopefully the last, Turkey Vultures constituted more than half of the birds counted. Their numbers were consistent with what we’ve seen the last several years. As a result, with the low total count, the number of non-vulture migrants at 5,511 was just 48.5% of the long term average. This is by far the lowest count of non-vulture raptors in the history of this watch site. The previous record low was set in 2007 when 7,561 birds represented 66.5% of the long term average. Clearly, this was a dreadful migration at our watch.

 

Often it is possible to reconcile poor counts with adverse local weather conditions. Too much precipitation, adverse winds, unusually low temperatures, etc. can often be used to explain why counts were low. None of this is possible for 2013. Furthermore, if the weather were to blame, how come the Turkey Vulture count appeared to be unaffected?

 

Another possible explanation is inadequate coverage but as can be seen on Table 1, the number of hours was consistent with the last couple of years albeit slightly below the 5-year and long term averages. There were four days when we didn’t have a counter but two of these were at the beginning of March when not many birds are moving and the other two were late in the season, one on a cool day with some rain. Certainly a lack of coverage cannot account for the low total count.

 

Let’s examine the year in more detail. Daily counts are provided on Tables 2-4 and the monthly totals are compared with previous seasons on Table 5.

 

The Season

 

Hawk watchers might be surprised to learn that the average mean temperature in March 2013 was more than a degree above normal. This despite the fact that on only two days did the temperature exceed 13ºC and even then just by about three degrees. The reason was that there were no very cold nights, -8.1º C was the lowest, and so the mean temperatures were normal. Precipitation, by contrast, was only 31% of normal. Two days had quite short count times and several days were slightly shortened, either to begin or by late onset of rain. Generally though the March weather was pretty fair and the monthly count was close to the long term average (Table 5).

 

April mean temperatures were normal on average but precipitation was well above normal (154%). It was almost all rain and much of it came between April 8 and April 12 including three straight days with over 20 mm each. All this precipitation resulted in somewhat lower hours of coverage than we usually have in our prime month (Table 5) as three days were wiped out completely and two others had severely curtailed observation periods. The number of birds counted was about 1,500 below the long term average for April but more than 3,000 below the recent 5-year average.

 

The first ten days in May were very pleasant and we had good coverage but the migration was almost non-existent. Then it turned quite cool for a few days with some rain and even snow on the 12th. Just as the season ended, it warmed markedly and the migration picked up a bit but the monthly count of 375 was well below the long term and recent 5-year averages of 1,168 and 608, respectively.

 

Only April 5th had a count of more than a thousand birds when a good flight of Turkey Vultures passed. April 15th had the best variety with 13 species and included a good count of 22 American Kestrels. The previous day there had been 12 Ospreys. Neither of these counts is a daily record for the species at Beamer but still nice to see.

 

Species Accounts

 

Black Vulture: While no BV show on the migration charts, they were seen at Beamer again this year. On April 23rd a group of four were seen heading west in the morning and then, presumably, the same four went back east three and a half hours later. Although not everyone agrees, it is our policy to only count net birds passing the watch site as a means of avoiding continuous counting of resident birds. While these birds are not residing near Beamer, they were possibly from the group that reside in Lewiston NY, about 45 km to the east.

 

Turkey Vulture: The 6,698 TVs represent the third highest total for the species and an 11% increase over 2012, one of only three species to increase in 2013. This year they constituted 55% of the raptors counted and when one considers how much activity there is by the local birds, they have truly become our dominant species.

 

Osprey: While down almost 20% from 2012, the count of 52 was still slightly greater than both the recent 5-year and long term averages. A record early date for Osprey was set on March 13th when Sandra Horvath had one pass between snow squalls. This bird was a full week earlier than the previous record set on March 20, 2000 and only the second one to be seen before March 26. In the early years of the watch, Ospreys were not seen in March at all.

 

Bald Eagle: The Bald Eagle count was close to the recent 5-year average and almost double the long term average. I suspect that one or other of the local breeding pair may have been counted on more than one occasion so that the 2013 total may be slightly greater than it should be.

 

Northern Harrier: The 77 Northern Harriers recorded in 2013 represents the second lowest count for the species in the history of the watch. Only the 72 birds recorded in 1980, the first year of full season coverage, was lower. In the five years since the count of 173 in 2008, the counts have declined each year. While very worrying, the historical pattern for this species is a series of increases and decreases and in fact the record high count occurred as recently as 2004.

 

Sharp-shinned Hawk: The 1,335 sharpies seen this year is more than 200 below the previous low count for the species and is only 19% of the maximum count of 7,004 in 1994. In the early days of the watch site, this was our most commonly seen species and in fact the sum total of sharpies since 1975 still ranks it as our second most numerous (after Broad-winged Hawks). There may be many possible explanations for this kind of decline but I wonder if it doesn’t reflect an overall decline in small bird populations in the woods. RPI analysis of the trend for the species has indicated a significant decline in their counts over the years and this year’s count will only augment that finding.

 

Cooper’s Hawk: For Cooper’s Hawks one has to go back to 1979 when we did not have daily counters to find a year with so few as we had in 2013. The 86 birds recorded this year probably also include some counting of one of the resident birds, which on this observer’s count days seemed to be particularly active. It is possible that there were two pairs within the vicinity of Beamer this year since on occasion there were three local birds in view. Certainly it was unlikely to have been counter bias calling possible Cooper’s Hawks as sharpies that caused the low total of Coops since the sharpies total was also very low. The total of 86 birds represents only 44% of the long term average for this species.

 

Northern Goshawk: The five goshawks seen this year is characteristic of recent non-irruption years for this species at Beamer, being near the recent 5-year average and well below the long term average of 20 that is much greater because of large irruption year flights. We are due for an irruption year, however, and typically there is an increase in the number of migrants the year or two prior to the peak. This didn’t happen in 2013 so we are still waiting.

 

Red-shouldered Hawk: Our signature species also set a record this year. The 437 birds counted was the lowest ever at Beamer, worse than the 455 in 2003. This is 71% of the recent 5-year average and only 60% of the long term average. Compared to many of the other species this year, this was a relatively good showing if a record low count can ever be considered good.

 

Broad-winged Hawk: Whereas two years ago we had a record high count this year we reached the nadir of a record low total. The 1,484 broadwings seen was below the previous record of 1,549 set in 1996. Even on a day like April 28th during prime time for this species and with favourable southeasterly winds, only 155 BWs were seen and most of these were well to the south of the tower. By comparison, the watch site near Rochester, NY had their best BW count of the season, over 6,000 birds that day.

 

Red-tailed Hawk: Another record low seasonal count with only 1,750 birds, breaking the previous record of 1,857 set just two years ago. This is another species whose counts are likely slightly inflated as a result of the activity of the resident birds. Two pairs were regularly seen from the tower, one along the escarpment edge and the other, including a bird with a damaged leg that hangs slightly when it flies, to the south of the falls. This has likely been true historically as well but reducing the count totals by a hundred or so birds each year would only increase the 36% decline from the long term average registered by this year’s total.

 

Rough-legged Hawk: The count of 38 birds seen this year was actually slightly more than last year. Counts for roughlegs are somewhat irregular because their migrations are more dependent on prey availability rather than seasonality than many other raptors. There have only been six years with counts below this year’s total so it was still one of our poorer years for this species too.

 

Golden Eagle: It was an average year for Golden Eagles at Beamer although the eight birds seen were below the recent 5-year average of 11.

 

American Kestrel: Perhaps the one bright spot in an otherwise dismal year was the fact that the kestrel count was the greatest since 2008 and about equal to the long term average at Beamer. The total of 92 birds was above the recent 5-year average of 69, an encouraging sign for this species. Of all the raptors that we see regularly at Beamer, American Kestrel is the one that RPI studies suggest has suffered the greatest population decline. For us to have an average year is good news.

 

Merlin: This was another species seen in average numbers in 2013 although the total of 12 birds is below the recent 5-year average of 16 and the lowest total since 2008.

 

Peregrine: Completing a sweep of average years for the falcons, the five Peregrines in 2013 were actually slightly more than the long term average of 4, albeit below the recent 5-year average of 8. It is questionable how many of these sightings actually represent migrating birds. The species is nesting both east and west of Beamer and the birds we see of this species are often moving in directions other than the east to west migratory direction for most birds.

 

No rare species were recorded this year.

 

Summarizing the species counts we see that the larger birds (Turkey Vultures, Bald and Golden Eagles and Osprey) were at or above their short term and/or long term averages and the falcons, as mentioned, were near their long term averages. The Northern Harrier and all the buteos and accipiters set record low counts in 2013, except for the two species, Rough-legged Hawk and Northern Goshawk, with irregular migration behaviour. That’s six species setting new lows in one year, the kind of record more typical of the second year of a watch site than the 34th year.

 

As usual our thanks go to the counters and assistants who volunteer their time and suffer whatever weather and flights they have on their assigned days. “Official” counters in 2013 were: John Barker, Bouwe Bergsma, John Black, Ed Couture, Sandy Darling, Tim Foran, George Holland, Sandra Horvath, Marcie Jacklin, Gord Kozak, Matt Mills, Brian Mishell, John Stevens, Mike Street, Tom Thomas, Phil Waggett, and Rob Waldhuber.

 

John Stevens

July 2013

 

2013 NIAGARA PENINSULA HAWKWATCH MONTHLY COUNTS

Species

March

April

May

Total

Black Vulture

0

0

0

0

Turkey Vulture

3051

3472

175

6698

Osprey

1

49

2

52

Bald Eagle

31

29

2

62

Northern Harrier

7

68

2

77

Sharp-shinned Hawk

44

1193

98

1335

Cooper's Hawk

34

41

11

86

Northern Goshawk

2

3

0

5

Red-shouldered Hawk

224

213

0

437

Broad-winged Hawk

0

1452

32

1484

Red-tailed Hawk

755

951

44

1750

Rough-legged Hawk

13

24

1

38

Golden Eagle

3

5

0

8

American Kestrel

9

79

4

92

Merlin

1

9

2

12

Peregrine Falcon

2

2

1

5

Unid. Accipiter

1

2

0

3

Unid. Buteo

13

37

0

50

Unid. Falcon

0

0

0

0

Unid. Eagle

0

0

0

0

Unid. Raptor

2

12

1

15

Total Raptors

4193

7641

375

12209

Hours Counted

212.85

185.58

90.75

489.2

Raptors/Hour

19.7

41.2

4.1

25.0

 

 
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