Total Counts Run and Total Species Found
In spite of Covid restrictions again this year, our data generally compared favorably with past years. This year we tallied data from 30 count circles of our total 34. Three counts did not run (Chester, Little Rocky Mountains, and Musselshell Valley) because of either covid issues, lack of field participants, or bad weather. One circle—Cut Bank—has been orphaned and needs a new compiler and some hearty souls to renew the count. If you can handle high winds and low temperatures, this might be the count for you.
Total number of species this year was—142 (Appendix 1), which equaled the average of the total number of species from the past seven years (CBC #115-121). This year we added no new species to our cumulative state list of 221.
We had seven Count Week (CW) birds this year that were not reported from any circle during a count day, including Ross’s Goose (Bozeman); Long-tailed Duck (Missoula); Red-breasted Merganser (Great Falls); Mew Gull (recently split, now Short-billed Gull but still Mew Gull in the CBC database; the bird was found at Bigfork); Barred Owl (Missoula); Gyrfalcon (Bigfork); and Gray Catbird (Missoula). Count Week birds were a bit higher than past years, perhaps because the fall and early winter were unseasonably warm in much of the state, and then the first sub-zero temperatures of the season descended just as the count period began. At least some of the waterfowl moved on due to iced-over ponds.
Bigfork had the high total count day number species for this year—90, followed by Missoula at 89. The record for the state is still 98 at Bigfork (CBC #118). The fewest species found was two at West Yellowstone (due to harsh weather) and nine at Upper Swan Valley. The average number of species found per circle this year was 50, which was one more than the average number of species seen from CBC #115-121. Even though the number of circles reporting data each year ranges from 29 to 34, the average number of species reported remains fairly constant.
Missoula had the highest number of participants at 125 (105 field participants and 20 feeder-watchers). The fewest—one—was at West Yellowstone, due to terrible weather on their count day. The average number of field participants was 21.
The total number of field participants (621) was about 13% lower than the average from the 7-year period of CBC # 115-121 (711). This year’s total feeder-watchers (155) equaled the average from CBC #115-121.
Total Individual Birds
We tallied 239,556 individual birds from 30 participating count circles this year. The total individual birds seen was the 2nd highest recorded, after CBC # 115 (243,285, Figure 1). This year’s total was 8% higher than the average number of individuals seen for the period CBC #115-121 (222,540).
Similar to last year, this year’s relatively high total number of individual birds 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 high numbers of individual birds despite fewer circles reporting and fewer field participants.
Combining this information, we can see that even though the number of field participants was below average (621 vs 711), the number of species recorded (142) was average, and numbers of individuals recorded was the 2nd highest recorded. One reason may be that participants have the local knowledge of where to seek out the highest diversity of species and highest numbers of individuals possible. That is, we had fairly good coverage of the circles, because we successfully found bird species and high numbers of individual birds, even though we had fewer field participants and only 30 of 34 circles running counts.
Another factor in explaining finding high numbers of individuals this year might be because, well, there were more birds to find. To explore this notion, I looked at the birds that numbered over 1000 individuals (Figure 2) in more detail.
Quantifying Increases in Birds
I wondered, did the species with high numbers this year have banner years, or average years and they are always high, or what was going on with them? To understand trends, recall that we use the metric birds per party hour to be able to compare trends for species across years. That is, raw numbers of birds is dependent on the amount of effort used to find those individuals, so using birds per party hour standardizes our data for comparison between and among years. For more information on this concept, see the National Audubon CBC website.
To evaluate increases in bird numbers, I compared the current metric of birds per party hour (that is, the total number of a species seen divided by the daytime effort for the year) to the average birds/party hour on record, which is available at the National Audubon CBC website.
Using this comparison, I found 16 species increased over 50% when compared to their preceding average birds per party hour (Figure 3). Keep in mind that the number of years averaged depends on the data available for each species, but generally the data begins in the 50s to 60s for most species. A few highlights are discussed below.
This year two species—Snow Bunting and American Coot—increased in birds per party hour by orders of magnitude, compared to their average from previous years. The graphs for both species look similar in shape, so I present Snow Bunting to illustrate both (Figure 4). Snow Buntings increased over 1000%, compared to the average birds per party hour from CBC #54-121.
American Coot increases (over 500% above average) were likely due to unseasonably warm conditions prior to count days. At Ennis Lake, for example, about a third of the area was ice free, such that the Ennis count tallied over 5600 coots this year (Robin Wolcott, Ennis compiler).
Most of the Snow Buntings from this year (around 6000) were tallied from the Fort Peck circle. John Carlson, the circle compiler, wondered if perhaps the birds were just more concentrated this year. He had noticed that there were many grain fields left unharvested from last fall (that is, there was not enough grain to mechanically harvest the fields without losing money). If conditions allowed the grain to be accessible (so not buried by snow), the birds may have congregated to take advantage of that food source.
Interestingly, although not as steep an increase as Snow Buntings, two other prairie species also increased this year—Horned Lark (over 150% increase from average, Figure 5) and Lapland Longspur (about 40% increase from average). These species’ numbers fluctuate widely from year to year, as depicted in the Horned Lark graph (Figure 5).
Other Finch Species
This year also appeared to be a good one for most of our finch species, with American Goldfinch leading the increases in birds per party hour, followed by House Finch, Common Redpoll, and Red Crossbill (Figure 3). Three of these species were fairly widespread, occurring on 26 (Common Redpoll), 24 (House Finch) and 20 (American Goldfinch) count circles. Red Crossbill was found on only 14 circles. Oddly, Cassin’s Finch, found on 10 counts, decreased about 60% from their preceding average birds per party hour.
American Goldfinch and House Finch graphs both show a marked increase in numbers and birds per party hour starting in the early 90s. American Goldfinch illustrates the point (Figure 6). Even with adjusting the average to reflect only these more recent years, both species still showed high increases from the average. American Goldfinch increased 48% when compared to the average birds per party hour from the period CBC #93-121, and House Finch increased 21% when compared to the average birds per party hour from the period CBC #94-121.
Several other species showed the American Goldfinch pattern of gradually increasing numbers to the 90s or so, followed by values that essentially cluster around a higher average during some more recent time period (Figure 6). These include Canada Goose, Northern Flicker, California Quail, Wild Turkey, Black-capped Chickadee, Red-winged Blackbird, Cedar Waxwing, American Crow, and Common Raven.
In contrast to the American Goldfinch graph shape, Common Redpoll, Red Crossbill, and Bohemian Waxwing graphs show ups and downs centered around a relatively stable average, similar to Horned Lark (Figure 5). This graph shape would be expected for eruptive or nomadic species.
One finch Species—Evening Grosbeak—has decreased in numbers, compared to the average birds per party hour from preceding counts (Figure 7), so the opposite of the American Goldfinch graph. While the species did increase this year compared to last year, their overall numbers are lower since the early 90s, when compared to period CBC #60-89. The species is now considered IUCN Vulnerable.
Common Raven was the most widespread species this year, found on 29 of 30 circles on their count days. Bald Eagle was the next most widespread species, found on 28 counts on count day and two count week circles, so all 30 counts were represented. They also showed a 56% increase compared to the average birds per party hour from the early 90s to present (Figure 8). Bald Eagles have made a remarkable recovery since the banning of DDT in 1972, but some individuals now face new challenges from lead poisoning from lead fragments found in gut piles and other carrion that eagles feed on. It will be important to see if widespread lead poisoning might decrease their overall numbers going forward.
Species that decreased compared to preceding average birds per party hour
Some numerous (over 1000 individuals recorded, Figure 2) species either showed essentially no change from average (Black-billed Magpie), or decreased when compared to their preceding average birds per party hour, including European Starling (27%), Common Goldeneye (20%), Mallard (19%, Figure 9) and House Sparrow (15%). The period for their averages generally ranged from the 40s or 50s through CBC 121. Rock Pigeon was essentially unchanged when compared to the long-term, but had about a 20% decrease from the recent period CBC #100-121. Ring-necked Pheasant numbers decreased about 10% since the 80s.
In summary, some species with high numbers this year were also higher than their preceding average birds per party hour metrics (e.g., Canada Goose, Bohemian Waxwing). Three species were exponentially higher than their past average birds per party hour (Snow Buntings and American Coot, and to a lesser extent, Horned Lark). We can use Figures 2 and 3 to see that not all species with high numbers this year were actually higher than their preceding average birds per party hour (Mallard, House Sparrow, European Starling). Some species seemed to have increased in recent decades, and had even higher averages this year, when compared to preceding average birds per party hour (Bald Eagle, Cedar Waxwing, Northern Flicker). It appears that at least 16 numerous species had essentially banner years this year (Figure 3).
Both Mourning Doves and Eurasian Collared-Doves increased in CBC 122, compared to last year (Figure 10). Eurasian Collared-Dove numbers may be starting to flatten out following an initial steep climb after they were first detected on counts in CBC #101; they increased 7% over the period CBC #112-122. Mourning Dove numbers may also be flattening out after high numbers reached during the early 2000s. Mourning Dove numbers are still substantially higher than during the period CBC #48-98.
One question arises—why were Mourning Dove numbers so high during the early 2000s? I wonder if some Eurasian Collared-Doves were mis-identified as Mourning Doves during the early part of that period. Before collared-doves were common and observers were used to seeing them, the observers would not have been clued into the presence of collared-doves and were likely not as adept at collared-dove identification. It seems reasonable that at least some Eurasian Collared-Doves were mis-identified as Mourning Doves during that time. But Mourning Dove numbers were still high in 2013, so participants would have likely been able to correctly identify the species by that time.
It is also possible that more people were feeding Mourning Doves during winter in rural portions of our count circles, and that winters have become more mild, so that some Mourning Doves stayed in Montana, rather than migrating south of Montana during winter. This combination of factors could account for the high Mourning Dove numbers that started in the early 2000s (Dave Lockman, Stevensville CBC personal communication). We would need to mark summering Mourning Doves in Montana to see if this change in migration pattern has occurred.
Rare and other Species of Interest
This year, we had few unexpected species. No warblers were found. Yellow-rumped Warblers have occurred regularly on our CBCs, often on the Billings count. No bluebirds of either species were found this year. We did have some ‘scarce but becoming regular’ species. Missoula tallied three Anna’s Hummingbirds. This species has been found on three previous counts, one bird from Billings (Dec 1982) and twice at Missoula (2 birds in Dec 2001, and one bird in Dec 2020). The birds were associated with feeders, as has been the case with recently overwintering individuals of this species. This year, Bozeman reported a Lincoln’s Sparrow with convincing details. The species has been found during 12 past count years (starting in the mid-70s), but it is unusual enough and hard enough to identify so that reports still need appropriate documentation. We had nine Lesser Goldfinches from three counts—Hamilton one, Kalispell two, Missoula six, and a count week bird from Bigfork. We also had three Lewis’s Woodpeckers (Missoula 1, Stevensville 2). Both of these species have become somewhat reliable in recent years.
This year we found seven owl species on count day and an additional species during count week, for a total of eight of the 13 potential owl species that occur in Montana during the winter. Two were relatively abundant—91 Great Horned Owls from 15 count circles and 25 Short-eared Owls from five circles. The other species were in single digits and included two Great Gray Owls from two circles, two Snowy Owls from one circle (Fort Peck) plus two count week birds from two others; nine Northern Pygmy-Owls from six circles, two Northern Saw-whet Owls from one count (Missoula), and five Long-eared Owls from three circles. The one CW bird was Barred Owl at Missoula.
The average number of owl species (count day plus count week birds) from CBC #115-121 is 8.6, so we were close to average during this year.
This year we missed Eastern and Western screech-owl, Barn Owl, Northern Hawk Owl, and Boreal Owl—which has only been found on two counts (Dec 1981 at Glacier National Park and Dec 2006 at Missoula). We would not expect Burrowing Owl on Christmas Bird Counts, because it is a summer breeder only in Montana.
This year, Rough-legged Hawks (783 birds from 24 circles and 1 count week bird) narrowly out-numbered Red-tailed Hawks (779, from 24 circles). We found an additional 35 Harlan’s type Red-tails from 10 circles, and five Ferruginous Hawks from three counts (all 3 east of the divide). We found all possible falcons (American Kestrel, Merlin, Prairie, and Peregrine) plus a count week Gyrfalcon (from Bigfork). Our least-likely winter falcon—Peregrine (because most migrate from Montana during winter)—was found on one count and one count week circle. Care must be exercised when identifying falcons during winter here. One Osprey with convincing details was reported from Bigfork.
This year produced the expected gull species—Ring-billed, Herring, and Glaucous, but only one California Gull (Fort Peck) and two Lesser Black-backed Gulls, one each from Helena and Fort Peck. Lesser Black-backed Gulls are getting to be regular each year in low numbers. Bigfork had a count week Mew (Short-billed) Gull, which is possible in winter but not found every year.
Thanks to all of our volunteers, and we hope to be out again next year without Covid restrictions and without high winds and deep snow.