Total Species and Cumulative List Increase
Despite Covid restrictions for this year, our data generally compared favorably with past years. Total number of species—140 (Appendix 1) was only slightly lower than the average of past six years (CBC #115-120, 143), and was higher than one of those years—139 during CBC #117. This year we added one species to our cumulative state list—a White-winged Dove from Bozeman, with photos (attached at the end of this report). The bird was found on count day, bringing our cumulative Montana species list to 222. We also added another species—Lark Sparrow in Missoula (with photos, found at the end of this report)—but it was only found during count week (CW), so it does not add to our cumulative list total. The bird over-wintered at a feeder in Missoula, a first for this species in Montana. While CW birds do not count toward our total list, we do track the species and they sometimes appear in subsequent years on count day. We had four other CW birds this year as well—Northern Hawk Owl at Glacier National Park; Barred Owl and Fox Sparrow at Missoula; and Lesser Black-backed Gull at Helena.
Missoula had the high total count day for species for this year—90, a record for that count. The record for the state is still 98 at Bigfork (CBC #118). Missoula also had the highest number of participants (102, 80 field-watchers and 22 feeder-watchers). The average number of total participants was 27, the fewest—3—was at McNeil Slough.
Total Individual Birds
We tallied 225,783 individual birds from 29 participating count circles this year (Figure 1). Montana has a total possible 34 count circles; five counts did not run this year. The total individual birds seen was higher than the average number of individuals seen for the period CBC #115-120, which was 222,000, but was not as high as tallied during CBC #120, and #115-116.
This year’s relatively high total individuals found may have resulted from better coverage of each circle, because teams were essentially arranged by household, with no carpooling of large groups. That is, we found many individual birds despite fewer circles reporting and fewer field participants (Figures 2 and 3) than during most recent years. Also, several circles had relatively open water this year and somewhat easy walking conditions—which facilitated better coverage of the areas, which in turn increased the diversity of habitats visited.
This year, a total 796 people participated on their respective count days as field participants (625, Figure 2) or feeder-watchers (171, Figure 3); some people did both activities and contributed to each total. While the number of field participants was about 13% less than the average from the past six years (CBC #115-120, 725), the total party hours this year (1577) was the highest of the past six years, and 15% higher than the average (1378) for that period. Recall that “party hours” is defined as daytime hours spent (via walking, driving or any other conveyance) by field participants only (that is, not feeder-watcher hours and not nocturnal owling hours). After the recording of bird species and their numbers, the tallying of party hours is the most important metric tracked by count compilers, because it drives the analysis of bird trends through time (more on that below). For this year, it appears field participants put in more effort in terms of total party hours, to presumably cover the circles as thoroughly as possible and with fewer people. Favorable count day conditions—for example fewer snowstorms and easy walking conditions from less snow cover—undoubtably contributed to higher effort (total party hours) this year. It is also possible that after being confined to our homes during the pandemic, many field participants felt more compelled to spend more time in the field on count day.
Feeder-watcher numbers (171, Figure 3) were higher than the average from the past six years (153) by 12%. While the number of feeder-watchers was similar to CBC #115 (168), the hours spent watching this year (450.38) was 27% higher than the average from CBC #115-120 (355 hours). Although anecdotal at this point, it is possible that more people confined to their homes this year resulted in people watching their backyard birds more closely. This may have contributed to the high number of feeder-watchers and high feeder effort hours this year.
Again this year and since CBC #115, Canada Goose (74,211 from 27 circles) and Mallard (38,178 from 26 circles) were the most abundant species found.
Recall that we use the metric birds per party hour (gray lines in the next 5 Figures) to compare trends between years, because the numbers of birds detected depends on how much effort goes into each count year. That is, using the metric birds per party hour allows us to compare apples to apples vs apples to oranges between years. I have included the actual bird numbers counted (orange line), to illustrate that the two metrics sometimes track fairly closely, but not always. In general, for Figures 4-8, the first CBC count listed was the first for which the species had recorded data.
Canada Goose numbers appear to have started climbing around CBC # 87 (Figure 4, gray line). Their numbers during CBC #121 (74,211) were above the average from the period #87-120 (38,839). However, birds per party hour during CBC #121 (47) was much higher than the average (32) during that period. This year’s numbers were also well below the records set last year (CBC #120, 89,095 birds and birds per party hour 62), both of which were the highest points for the species for Montana in any CBC since #51, the first year for which we have data (Figure 4).
Mallard numbers also vary widely between years (Figure 5). This year’s total (38,178) was higher than the average from CBC #45-120 (just over 18,000). Birds per party hour this year (24) was similar to the average from the period #45-120 (25). The most recent high for birds per party hour was nearly 64 during CBC #100.
Prior to CBC #45, there were three abnormally high Mallard birds per party hour values (ranging from 122 to over 700). Because I have no way to confirm the total party hours for those years, those data were not included in this analysis, so that the ranges of birds per party hour (0 to 90) would be easier to read on this graph.
Next most numerous was European Starling (13,450 from 25 circles), another species whose numbers fluctuate widely between years (Figure 6). Numbers have gradually increased since about CBC #88 (gray line), although they appear to have declined since #118. This year’s numbers were well below the recent peak of CBC #116, at nearly 25,000 birds and birds per party hour just over 18.
Any Montana birder can tell you that Bohemian Waxwings likely show the widest fluctuations through time, clearly seen in Figure 7. During some winters they can be frustratingly difficult to find. This year’s apparently low numbers (gray line) are well in line with other low years (CBC #87, 99, 103-104, 119 for example).
The only other species over 10,000 individuals tallied this year was House Sparrow, (Figure 8, 10,715 birds counted from 23 circles).
It appears that House Sparrow numbers have been fairly steady (gray line) since around CBC #85, between 6 and 14 birds per party hour. These metrics also appear to be well below the high birds per party hour reported from the period CBC #39 to about #74. This possible population decrease has been noted in declines described in Birds of the Works online— “Trends measured by Breeding Bird Survey (BBS) data show (North American) continent-wide population decline for period 1966-2004” for House Sparrows.
This year, as in every year since CBC #115 (except for last year), Bald Eagle was the most widespread species, found on 28 count day circles and one CW circle (Upper Swan Valley), so 29 of 29 counts were represented. Next most widespread was Black-capped Chickadee—on 27 counts. Mallard and Black-billed Magpie were tied with 26 counts and each with one CW site, so 27 circles of 29 represented. Last year’s most widespread species was Common Raven, found on 25 counts this year. Other species found on 25 counts were Common Goldeneye, Northern Shrike, Red-breasted Nuthatch, and European Starling. All other species were on fewer than 25 counts. The above-listed species are generally the most widespread every year, although the order often varies.
Rare and other Species of Interest
This year, Missoula tallied an Anna’s Hummingbird; the species has been found on two previous counts (Billings 18 Dec 1982 and Missoula 15 Dec 2001 [Marks et al., 2016]). The bird was associated with a feeder, as has been the case with recently overwintering individuals of this species. Two warblers were found— a Common Yellowthroat with convincing details from Troy, and a whopping 13 Yellow-rumped Warblers from Billings (9 birds), Missoula (1), and Great Falls (3); Troy also reported a CW bird. Yellow-rumps occurs regularly on our CBCs, often on the Billings count. However, this was only the 3rd CBC for Common Yellowthroat—found on a count that no longer runs (Bighorn River) on 22 Dec. 2001, and Stevensville on 5 Jan 2005 (Marks et al., 2016). Missoula also tallied two Green-tailed Towhees—always an unexpected sighting from west of the divide in Montana. The species has been seen on four past CBCs—single birds from Park Co (29 Dec 1990), Yellowstone National Park (22 Dec 2002), and Ennis (16 Dec 2015, [Marks et al., 2016]), and two birds from last year (CBC #120) also from Yellowstone National Park. This year we found two Mountain Bluebirds, one each from Helena and Fort Peck, both on count day. The species has been reported during seven past CBCs, from #47 to #119. This year we also had five Lesser Goldfinches, from a feeder in Missoula. The species has become relatively reliable in recent years and has been reported from three past CBCs—during #113 (Missoula), #119 (Hamilton and Three Forks) and #120 (Hamilton).
This year only one count tallied Greater Sage-Grouse, a state species of concern, with one bird found at Bowdoin National Wildlife Refuge. At least one count that had reported this species in the past did not run this year—Big Hole. To more easily visualize these low birds per party hour values, I created Figure 9 without the highest birds per party hour—0.31 from CBC #40. For this year, birds per party hour was 0.0006, which was the lowest ever recorded, but it was similar to counts #111 and #114 at 0.0008, and counts #89 and #95 at 0.0009, which were the next higher values recorded. As noted last year, CBCs are not highly suited to evaluate Greater Sage-grouse populations, because the counts often do not occur where the birds spend the winter, and winter access can often be challenging.
This year we found six count day and two CW, or eight of 13 potential owl species that occur in Montana during winter. Three were relatively abundant—98 Great Horned Owls from 18 count days, plus two CW circles; 10 Northern Pygmy-Owls from six circles, and 33 Long-eared Owls from three circles plus one CW circle. The other three species were in single digits (Great Gray Owl, Short-eared Owl, and Northern Saw-whet Owl). The two CW birds were Northern Hawk Owl at Glacier National Park and Barred Owl at Missoula. The average number of owls (count day plus CW birds) from CBC #115-#120 is 8.7, so we were close to average during this year.
We missed Eastern and Western Screech-Owl, Snowy Owl (although there were individual present this winter); Barn Owl (although at least 1 was present before CW at 1 circle); and Boreal Owl—which has only been found on two counts (18 Dec 1981 at Glacier National Park and 16 Dec 2006 at Missoula, [Marks et al., 2016]).
This year, both Mourning Dove and Eurasian Collared-Dove birds per party hour values were lower since their recent peaks during CBC #117 (Figure 10). The metric birds per party hour has declined for both species to a similar degree since #117. While this year’s Mourning Dove value (0.2448) is the lowest since CBC #99 (0.2874), this year’s value is still higher than all reporting years from CBC #48-#98. Note that Mourning Dove values were especially high during the period from CBC #101 to about CBC #113—essentially the period when collared-doves were dramatically climbing. And while Mourning Dove numbers appear to have declined for the last four counts, so too have collared-dove numbers. These data suggest that Eurasian Collared-Doves have not had a negative effect on the numbers of Mourning Doves, contrary to the notion of many Montana birders.
Please note that the scale for each species is different, so that while the trend direction can be compared, the ultimate values for collared-dove is about five times the value for Mourning Dove. Also, although perhaps hard to see, collared-doves were first reported on a Montana CBC in #101, and were first detected in Montana during the summer of 1997.
Hawks and Falcons
This year we tallied 674 Red-tailed Hawks from 21 counts, and an additional 30 Harlan’s type Red-tails from eight counts. We also found all possible falcons (American Kestrel, Merlin, Prairie, and Peregrine) except for a Gyrfalcon (although individuals were present this winter). Our least-likely winter falcon—Peregrine, because most migrate from Montana during winter—was found on two counts and totaled four birds.
This year produced the expected gull species—Ring-billed, California, Herring, but only one Glaucous Gull (Kalispell, although 2 CW birds [Big Fork, Great Falls] were recorded). One Lesser Black-backed Gull—getting to be regular each year in low numbers—was recorded CW in Helena. Fort Peck—usually our winter gull capital—was shut out of the honors for rare gulls but did produce our only American White Pelican. Scattered pelicans have been found on 18 past CBCs since #83.
Thanks to all of our volunteers, and we hope to be out again next year without distancing and with masks only if necessitated by high winds.
White-winged Dove—new CBC record for Montana—the bird was reported from 16 Nov 2019 to 8 Jan 2021, and likely would have overwintered but was taken by a Sharp-shinned Hawk 8 Jan 2021. Photographed on count day (19 Dec 2020) by Kevin Ellison, Bozeman, Montana CBC.
First over-wintering record (reported 13 Dec 2020-12 Feb 2021) of a Lark Sparrow, CW bird for Missoula CBC, photo by Jalalieh Morrow
Birds of the World online, Cornell lab of Ornithology
Marks, J. S., P. Henrdricks, and D. Casey. 2016. Birds of Montana, 259 pp., Buteo Books, Arlington, VA.