114th CBC Michigan Regional Summary

By John Trapp

The 114th Christmas Bird Count (CBC) yielded results from 69 Michigan circles, the most ever conducted. A total of 518,372 individuals of 149 definitive species was documented, with an additional four species reported during count week but not on count day. Two circles exceeded 30,000 individuals (Rockwood 39,085 and Anchor Bay 32,117), while five others exceeded 20,000 individuals. Three circles reported more than 80 species (Port Huron 88, Berrien Springs 85, and Anchor Bay 83), with another six circles exceeding 70 species. Following two exceptionally mild winters, participants in the 114th CBC were either rudely or pleasantly, depending on one’s perspective, reminded of what a Michigan winter is really like: compared to the 2012-2013 count period, daily snowfalls were 132% more frequent, snow cover was 50% more prevalent, and snow depths were 2.7 times greater.

Well-documented vagrants or seasonal rarities (species with annual frequencies of less than 50% in the previous 10 years) included the following: Ross’s Goose—a total of four birds, with two each at Allegan State Game Area and Hudsonville (singles were seen in 2009 and 2011); Western Sandpiper—one at Rockwood (Michigan’s 1st confirmed CBC sighting); Black-legged Kittiwake—a count-week sighting at Muskegon (singles in 2004 and 2011), Mew Gull—one at Battle Creek (the 1st reported on a Michigan CBC, although at least two previous Michigan records fall within the CBC period); Fish Crow—one at New Buffalo (Michigan’s 1st count-day report—there was a count-period report in 2011—constitutes a continuation of sightings in extreme southwestern Michigan since 2009); Varied Thrush—one at Dowagiac (singles in 2004 and 2007); Pine Warbler—one at Bay City (singles in 2004 and 2007), Vesper Sparrow—one at Mount Pleasant (singles in 2005 and 2008); Savannah Sparrow—a total of three birds, one at Anchor Bay and two at Rockwood (singles in 2005, 2007, 2010, and 2012); Harris’s Sparrow—a total of two birds, with singles at Eagle Harbor and Houghton County (1 in 2004); and Summer Tanager—one at Marquette (singles in 2003 and 2009).

Borderline species, those detected in five or six of the previous 10 years, are so-defined because with only a modest change in annual frequency they could move upward into the frequent category or downward into the infrequent category. Seven borderline species were reported this year: Greater White-fronted Goose—10 at Berrien Springs (reported in 5 of the previous 10 years and averaging 1.4 birds/year); Harlequin Duck—one at Manistee plus a count-week sighting at Ludington (6 of 10 years and 1.5 birds/year); Northern Bobwhite—a count-week sighting at Niles (6 of 10 years and 2.8 birds/year); Sharp-tailed Grouse—45 (26 at Neebish Island-Dunbar and 19 at Les Cheneaux; 5 of 10 years and 4.5 birds/year); Townsend’s Solitaire—a count-week sighting at Ludington (6 of 10 years and 0.8 birds/year); Common Yellowthroat—one at Anchor Bay (6 of 10 years and 1.4 birds/year); and Chipping Sparrow—one at Port Huron (6 of 10 years and 3.8 birds/year).

Of the 149 species recorded on count day, 134 are considered to be of frequent occurrence on Michigan CBCs, having been recorded in seven or more of the previous 10 years. The remainder of this review will focus on the 54 frequent species reported in numbers that were above or below expected levels based on historical CBC results. The status of a species is considered to be “changed” (i.e., substantially above or below average) if the number reported was more than one standard deviation above or below the average of the previous 10 years. That analysis reveals that 28 (21%) of the 134 frequent, or expected, species detected on the 114th CBC were present in above-average numbers, 26 (19%) were below average, and 80 (60%) did not differ markedly from their respective 10-year (2003-2012) averages. Five other species seen frequently in recent years went undetected: Great Egret, Purple Sandpiper, Boreal Chickadee, Brown Thrasher, and Red Crossbill. Looking at changes in numerical abundance of 139 frequent species from 2012 to 2013, we find that 59 species (43%) remained essentially unchanged (continuing in above-average, average, or below-average numbers) while 79 (57%) switched from one numerical abundance category to another, 31 in a positive direction (from lower to higher abundance) and 48 in a negative direction (from higher to lower abundance). Among the subcategory of 79 species switching from one abundance category to another between the two years, 12 underwent extreme changes, seven from abundance to paucity (Tundra Swan, Ring-necked Duck, Red-necked Grebe, Bonaparte’s Gull, American Kestrel, Black-capped Chickadee, White-breasted Nuthatch) and five from paucity to abundance (Red-headed Woodpecker, Blue Jay, Gray Catbird, Cedar Waxwing, Yellow-rumped Warbler).

Eight of the 29 species of waterfowl that are recorded frequently on Michigan CBCs deviated significantly from the 10-year average. Snow Goose (45 birds, the most in 8 years) was up 86%; Trumpeter Swan (225 birds, 2nd only to the 266 last year), continuing to benefit from recent reintroduction efforts, was up 39% after being up 86% last year; the more highly migratory Tundra Swan (2468 birds, the 3rd fewest in last 10 years) was down 44% after being up 54% last year; Gadwall (3376 birds, 2nd only to last year’s 3927) continues an amazing turn of fortune, up 175% after being up 331% last year; American Black Duck (2438 birds, the most in 24 years) was up 78%; Canvasback (18,825 birds, the 2nd fewest in 9 years), whose numbers on Michigan CBCs may show an inverse relationship with icing conditions on lakes Huron and Superior, rebounded slightly from last year but remained below average (down 64%) for the second year in a row; Ring-necked Duck (1390 birds, the 2nd fewest in 13 years) was also down 64% this year after being up 162% last year; Common Merganser (10,488 birds, the fewest in 8 years), a species whose numerical abundance on Michigan CBCs has declined from nearly 20,000 birds/year (1980-2003) to just over 10,000 birds/year (2004-2013), was down 74% this year. Returning to more normal numbers following their unusual abundance last year were Canada Goose (58,983 birds), Mute Swan (3725 birds), American Wigeon (31 birds), Mallard (37,172 birds), Northern Shoveler (15 birds), Northern Pintail (348 birds), Green-winged Teal (18 birds), Bufflehead (1784 birds), Hooded Merganser (413 birds), Red-breasted Merganser (1950 birds), and Ruddy Duck (1731 birds). Redhead (5313 birds) bounced back to usual numbers after being depressed last year.

Ruffed Grouse (98 birds, the fewest in 8 years) was down 31%. Red-throated Loon (98 birds) exceeded the 10-year average by 10-fold with 94% of individuals at New Buffalo on the shores of southern Lake Michigan, tempting speculation that this unusual concentration was somehow related to the unseasonably early build-up of ice on the upper Great Lakes. Pied-billed Grebe (10 birds, the fewest in 9 years) and Red-necked Grebe (1 bird, the fewest in 14 years) were down 60% and 95%, respectively. Freezing temperatures and heavy snowfall had not yet affected the Great Blue Heron (587 birds, the 3rd most in the last 10 years), whose numbers were 21% above normal. Horned Grebe (51 birds) and Double-crested Cormorant (56 birds) returned to normal numbers after their unusual abundance last year.

The Bald Eagle (597 birds, a new high) continues its relentless upward trend, being 48% above the 10-year average this year. Northern Goshawk (9 birds, the most in 12 years) was up 70%, Red-shouldered Hawk (55 birds, following last year’s record high of 56) was up 82%, Red-tailed Hawk (959 birds, the fewest in 14 years) was down 30%, and Golden Eagle (3 birds) was up 100%. Turkey Vulture (12 birds) returned to normal after being up last year, while Sharp-shinned Hawk (88 birds), Cooper’s Hawk (247 birds), and Rough-legged Hawk (152 birds) rebounded after being down last year.

Wilson’s Snipe (7 birds, the most in 14 years) was up 192%. Among the gulls, Bonaparte’s (a mere 198 birds, the 3rd fewest in 12 years) was down a whopping 87% after being up 250% last year, Ring-billed (10,544 birds, the fewest in 24 years) was down 54%, and Herring (15,733 birds, the 3rd fewest in the last 13 years) was down 17%. Bucking an otherwise downward trend among the gulls, Lesser Black-backed (15 birds, the 2nd highest ever) increased for the third year in a row, being up 58%. Also, American Coot (3361 birds), Sandhill Crane (721 birds), Killdeer (3 birds), Iceland Gull (1 bird), and Glaucous Gull (26 birds) all returned to more usual numbers after being unusually abundant last year, while Purple Sandpiper went undetected for the first time in five years.

Both of Michigan’s regular columbids were present in greatly reduced numbers: Rock Pigeon (11,029 birds, the fewest in 31 years) was down 30%, leaving one to question whether numbers were really reduced to that degree or if observers simply overlooked them, while Mourning Dove (17,866 birds, the 2nd fewest in 22 years) was down 25%. To say that the Snowy Owl incursion was the event of the season would be a vast understatement. Numbers of Snowy Owls detected on Michigan CBCs have been noticeably reduced in recent years, from 0.34 birds/count (1975-1993) to 0.10 birds/count (1995-2012). In light of this downward trend, the magnitude of this year’s invasion (some 9 times the 10-year average) is not only impressive but particularly gratifying. There was an inverse correlation between latitude and the probability of encountering a Snowy Owl, the latter value ranging from 15% of circles in the Upper Peninsula to 41% in the Northern Lower Peninsula and 58% in the Southern Lower Peninsula. Definitive numbers are hard to pin on this ghostly wanderer from the north, but the 2013-2014 spectacle was clearly one of the top four or five incursions of the last 50 years.

Belted Kingfisher numbers (121 birds) were within the normal range after being up last year. Red-headed Woodpecker (106 birds, the most in 19 years) was up 159%, Yellow-bellied Sapsucker (51 birds, the most in more than 33 years) was up 185%, Downy Woodpecker (2813 birds, the fewest in 13 years) was down 19%, and Pileated Woodpecker (310 birds, a new record high) was up 39%. American Kestrel (185 birds, the fewest in 13 years) was down 42%. Meanwhile, Northern Flicker (523 birds) returned to normal after being down last year, while Merlin (15 birds) and Northern Shrike (85 birds) were again within the normal range after being up last year.

Crows and jays through kinglets exhibited confusing patterns of variation, with six species being up and five down. On the up side, Blue Jay (11,423 birds, the most in 8 years) was up 27%, Common Raven (697 birds, the 2nd most in the last 10 years) was up 35%, Horned Lark (2946 birds, the most in 13 years) was up 116%, Brown Creeper (313 birds, the 3rd most in the last 12 years) was up 18%, Carolina Wren (231 birds, the most in 7 years) was up 30%, and Golden-crowned Kinglet (562 birds, the most in 13 years) was up 69%. On the down side, Gray Jay (3 birds, the 3rd fewest in 13 years) was down 67%, American Crow (29,552 birds, the fewest in 11 years) was down 25%, Black-capped Chickadee (14,913 birds, the fewest in 9 years) was down 14%, White-breasted Nuthatch (2875 birds, the fewest in 13 years) was down 21%, and Winter Wren (12 birds, the fewest in 12 years) was down 30%. Boreal Chickadee, averaging 2.1 birds/year, was not seen this year. The irruptive Red-breasted Nuthatch (859 birds) was within the usual range following their unusual abundance last year.

American Robin (6450 birds, the most in 9 years) and Gray Catbird (7 birds, the most in 10 years) fared well despite the generally inclement weather, being 54% and 94% above average, respectively. Brown Thrasher, detected in eight of the previous 10 years but averaging just 1.3 birds/year, was a no-show. Northern Mockingbird (8 birds) returned to more usual numbers after being up last year. The highly irruptive Bohemian Waxwing (8 birds) returned to “normal” numbers after being up last year. Cedar Waxwing (6627 birds, the most in 11 years) was up 28%, Lapland Longspur (2795 birds, the most ever) registered an incredible 306-fold increase, and Yellow-rumped Warbler (243 birds, the most in 11 years) was up 197%.

Amidst the nine species of emberizids that appear frequently on Michigan CBCs, only one deviated appreciably from normal: Dark-eyed Junco (22,326 birds, the most in 12 years) was up 57%. White-throated Sparrow (337 birds) and White-crowned Sparrow (71 birds) returned to normal numbers after being depressed each of the last several years. Northern Cardinal (7109 birds, the 2nd fewest in 11 years) was down 11%, Brown-headed Cowbird (520 birds, the fewest in 32 years) was down 58%, Pine Siskin (92 birds, the fewest in 37 years) was down 93%, and House Sparrow (18,720 birds, the fewest in 45 years) was down 34%. For the most part, winter finches remained north of Michigan this year, with Pine Grosbeak (9 birds), White-winged Crossbill (1 bird), Common Redpoll (11 birds), and Pine Siskin (92 birds) all down more than 90%. Red Crossbill was entirely absent, and Evening Grosbeak (71 birds, the 2nd fewest in 7 years) was down more than 50% from a 10-year (2003-2012) average already just a fraction (about 5%) of the numbers seen in the 1970s and 1980s.

Given that one of the attractions of participating in the CBC is the possibility of finding rarities, let’s look at some statistics on the role that rarities play in Michigan CBCs. In addition to the two new species added to the CBC checklist this year (Western Sandpiper and Fish Crow), there were frequent additions to the species lists of individual circles. Twenty-seven (51%) of 53 circles with 10 or more years of CBC data added an average of 1.6 new species. The most frequent local addition was Snowy Owl (newly reported on three circles), followed by Trumpeter Swan, Great Black-backed Gull, Gray Catbird, Lapland Longspur, and Fox Sparrow with two each. If a rarity is defined as a species encountered on fewer than about 10% of historical counts within a given CBC circle, we find that 87% (46) of 53 circles with a history of 10 or more counts detected at least one rarity. Furthermore, among those circles in which rarities were detected, they accounted, on average, for about 4.5% of all species and 0.18% of all individuals. Thus, it can be seen that the likelihood of encountering a rare or unusual species during a Michigan CBC is indeed an unusual event.

Once again, I thank the army of participants who brave the elements to gather the data that help to document trends in Michigan’s regularly occurring winter birds while seeking to lay eyes on the rare, unusual, or unexpected individuals lurking among them. Thanks are also extended to the compilers, who are responsible for the behind-the-scenes work that makes compilation of this report possible. I am honored to work with them all. Finally, heartfelt thanks to Adam M. Byrne and Jonathan T. Wuepper for help in the reviewing and evaluating reports of rarities, thus enhancing the quality of the database.