The 115th Christmas Bird Count

One-hundred fifteen years is a long time in the human perspective, and also when used to gauge the life of human activities; in that respect, Audubon’s Christmas Bird Count is a grizzled old codger of a program. It’s even five years older than the National Audubon Society itself! By other measures, a century—100 years, 1200 months, 5217.75 weeks, or 36,524.2 days—is just a blink, a flash, or a miniscule increment on an evolutionary or geological timescale. But a biological inventory that spans centuries can illustrate hugely important stories, both human and ecological. And as we move well into the second century of the Christmas Bird Count, its relevance and importance to our understanding of the status of birds in the Americas—and the effects of climate change on them—grows with each passing season.

However, all that isn’t why most CBC folks devote considerable time and effort to the program during their already busy holiday seasons. We do it because it’s a great excuse to get outside and do some birding, often with friends that we only see once or twice a year—usually on CBCs. We do it because we know our areas, and are excited to try to find some new species toward the end of the year for our annual lists. And we do it for the anticipation of experiencing some type of interesting natural event, whether that is a major irruption of winter finches, mind-boggling experiences with boreal raptors, or the discovery of an unusual species during the day.

While it seemed unlikely to most birders that during the winter of 2014-2015 we would have a fourth season in a row with significant numbers of Snowy Owls moving southward into the populated mid-latitudes, word had been filtering down that indeed there had again been a good breeding season for these spectacular owls. However, it was farther west and considerably farther north than the area of high breeding density during the summer preceding the 114^th CBC and its record Snowy Owl flight. Additionally, Ron Pittaway’s annual “winter finch forecast” predicted that finches and winter frugivores would likely mostly stay north in the boreal forests, where various seed and fruiting crops were good. But many of those finches are notoriously wayward in their wanderings, and birders always hold out hope for a chance encounter. So we took to the field and watched our feeders, binocs around our necks and scopes over our shoulders, anticipating whatever awaited us in the early winter.

In the end, the 115^th Christmas Bird Count was yet another record-breaking season. For the sixth season straight the bar was raised for both number of counts included and level of participation—2462 circles covered all told (54 more than last season’s short-standing record); 1888 in the United States, 460 in Canada, and 114 in the Caribbean, Latin America, Bermuda, and the Pacific Islands. The alphabetical roster of countries and protectorates included remains the same as during the 114^th CBC—the Bahamas, Belize, Bermuda, Brazil, British Virgin Islands, Colombia, Canada, Costa Rica, Cuba, the Dominican Republic, Ecuador, El Salvador, Guam, Guatemala, Haiti, Mexico, Nicaragua, the Northern Marianas Islands, Panama, Puerto Rico, St.-Pierre et Miquelon, Trinidad, the United States , and the U.S. Virgin Islands. Not surprisingly in that very grand total is a considerable number of new counts—58 in total, ranging from northern Canada to tropical Colombia—and they are listed in Table 1. Welcome aboard all, and we look forward to many years of successful counting in all your circles.

A Look at the Numbers

It takes lots of birders to make all those CBCs happen, and again record numbers of observers (as might be expected) participated in the 115^th Christmas Bird Count season. We broke the 114^th CBCs record total by just under 1000 observers—this season’s totals was 72,653 all told, with 62,211 in the field and 10,442 watching feeders. North to south and region by region, there were 10,123 afield and 3918 at feeders for a total of 14,181 observers in Canada; 49,604 in field and 6405 feeder watchers for 56,009 observers in the United States; and 2484 field observers and 119 feeder watchers in all other countries combined. Managing all that people power falls on the task list of the compilers of counts across the hemisphere and beyond, and keeping track of 100 or more observers can be quite a job. Table 2 lists the counts from across the Western Hemisphere with 100 or more observers—81 CBCs this season—great kudos to all!

All those birders in all those count circles across the Americas and beyond (the far-flung U.S. Protectorate Islands in the Pacific tally some fascinating birds) are pretty well guaranteed to tally lots of birds, and in the 115^th Christmas Bird Count a total of 68,753,007 birds are included (64,818,439 in the United States, 3,505,029 in Canada, and 429,539 elsewhere). That total is certainly in the ballpark average for much of the past quarter century; the only event that can change the total much is during the rare seasons like the 88^th CBC where tremendous roosts of mixed blackbirds were found in one circle at Pine Prairie, Louisiana. In that season that one count had more birds than are usually found by observers in all circles everywhere! Such is the challenge of studying numbers of congregatory species that form huge winter roosts, especially with a program like the Christmas Bird Count and Breeding Bird Survey where specified areas are covered each season. If the big roosts aren’t where the counting takes place, they’re missed.

Given the geographic scope of the Christmas Bird Count, it’s no surprise that a significant proportion of the birds of the world get counted, and during the 115^th CBC the full total was 2106 species, roughly one-fifth of the avian taxa on Earth. In the United States, 655 species and an additional 66 identifiable forms were tallied, while in Canada 305 species were tallied. While no new native species were officially included in the U.S., by some measures one was—the male Eurasian Siskin present for some time in a flock of Pine Siskins and White-winged Crossbills on Unalaska Island, in the Aleutian Chain of Alaska. There is one previous record of this species in the CBC database, but it was of a female-plumaged bird and recent studies on Pine Siskins have shown that there is a small proportion of “green morph” Pine Siskins that are inseparable in the field from female Eurasian Siskins. So keep your eyes out in those siskin flocks devouring the nyjer seeds outside your window—you never know what will turn up in them! Canadian CBC participants had better luck finding new species for the cumulative Canada CBC list; Tennessee Warbler at Peel-Halton, Ontario, Black-throated Green Warbler at Cape Sable, Nova Scotia, and Eurasian Tree Sparrow at Winnipeg, Manitoba were all new to the CBC in Canada.

We measure the success of our Christmas Bird Counts by many yardsticks, and one of the most common is our final species total for the season. Observer effort, weather, the birds themselves, and just plain luck are all major factors in the equation that sums our species totals, and Table 3 is the list of 129 counts (91 in the United States and Canada and 38 in Latin America) that tallied 150 or more species. Once again Matagorda County-Mad Island Marsh, Texas at 234 species in the US/Canada and Yanayacu, Ecuador at a mind-boggling 529 species in Latin America top their respective regions. So why does it seem that the same counts always get the highest species diversity on CBCs? It’s all in geography. The coastal Texas (and California) counts are blessed with varied habitats, southerly latitude within North America, and lots of observers. And the counts in Ecuador (and of course other countries in Latin America) are smack in the middle of the incredibly diverse Neotropical forests, often with great variation of altitude within the circle. Thus lots of species diversity in coastal Texas and in the Andes of South America. But there’s another way to look at things—the number of birds (rather than species) tallied. Yes, folks at Yanayacu found 529 species, but the total number of birds tallied was 5507 individuals, and it’s likely that most of those were by voice only. Looking at a count in southern Canada, Point Pelee, Ontario (and that with good diversity of habitat, being on Lake Erie), “only” 81 species were tallied, but they found 72,825 birds. Bismark-Mandan, North Dakota counters tallied 54 species—and 31,310 birds. Most of these birds were probably seen, not heard. So yes, for the big species tallies head to the Neotropics—but to see lots of birds, it is counts in the higher latitudes that are the destination!

Regardless of latitude or longitude, and given that most observers don’t have the option of heading to far-flung destinations to do their Christmas Bird Counts, we often measure our local count’s success by comparing our species total with those of neighboring circles. Folks in the Yukon Territory or Idaho can be proud of their standing compared to other circles in their nearby regions, and don’t need to worry about how they compare to California, Texas, or Costa Rica. Table 4 contains the list of regional high counts during the 115^th CBC—take a look and compare, but don’t despair! Every area of every count has its own highlights and rewards each season. Speaking of yardsticks, don’t forget to take a look at Brent Ortego’s Summary of High Counts for the United States and Dick Cannings’ Summary of High Counts for Canada—you may be pleasantly surprised to find your CBC listed.

Trends Upon Trends

By the way, this season was Dick Cannings’ last as the Canadian coordinator for the Christmas Bird Count. Dick has been a great friend and ably managed the count in Canada since the beginning of the agreement with Bird Studies Canada and the National Audubon Society to have BSC coordinate the program in Canada. Dick has also been doing the CBC regional editing for British Columbia and other areas in western Canada since the 83^rd CBC, so he has a long history of guidance and good cheer for the CBC in Canada. Dick was recently elected to Parliament in Ottawa, and needs to relinquish his position with Bird Studies Canada. I can’t thank Dick enough for his friendship and sage advice over the years—but I’m sure he’ll still be involved with the CBC as a participant (and hopefully still regional editor).

All things considered, the 115^th Christmas Bird Count had other interesting aspects. Weather-wise, you’d have to say it was “average”, with mild and pleasant conditions over much of northeastern North America during most of the count period, a cold blast prior to the 115^th Count period in many northern regions, and sporadic inclement and cold weather over much of the rest of the North American continent. Perplexingly, pleasant conditions on count day in any given region may mean that birds are hard to find, and this phenomenon presented itself in many areas during the 115^th CBC. When the weather is bad birds need to concentrate in the areas where observers expect to find them during the CBC, but when conditions are favorable birds are spread out across the landscape. Given the cold snap prior to the 115^th count period and pleasant conditions during the count period, for many folks birds were just plain hard to find.

It is interesting to note that lingering neotropical migrant species seem to be increasing in frequency across many of the northern regions of North America. Look at two of the new additions to the 115-year cumulative Christmas Bird Count list for Canada—Tennessee and Black-throated Green warblers. These, among other long-distant migrant warblers, thrushes, and tanagers, are increasing in occurrence on Christmas Bird Counts across much of the United States and Canada. Is it possible that there are just more experienced birders out there noticing and identifying these birds? Yes, of course that is possible. But given the moderating fall and early winter conditions over most of North America, it also seems likely that tardy neotropical migrants are better able to survive for longer periods in the northern regions of the Americas—and thus are noticed and tallied on an increasing number of CBCs across the United States and Canada. Swainson’s Thrushes, Scarlet Tanagers, and several species of warblers were considered “impossible” on North American CBCs even a decade ago, yet now with impeccable documentation they are being included on an increasing number of CBCs across the United States and Canada. Each year the data submitted helps to give us insights into where birds are moving.

While most “winter finches” stayed north in droves for the 115^th Christmas Bird Count, a few species did move across the continent. Cedar Waxwings, Pine Siskins, and Purple Finches pushed southward in the eastern United States as far as the Carolinas and Georgia, but never reached northern Florida in significant numbers. Continuing recent trends, Eurasian Collared-Doves consolidate their range with a northwestern vector (as they have done over many regions globally in recent decades), with increasing numbers in western Canada and southeastern Alaska, even reaching the “mainland” of Alaska for the first time this season. Interestingly, these adaptive doves have decreased significantly in number in the Southeastern United States where their initial colonization occurred. Could this be the beginning of an equilibrium of Eurasian Collared-Dove numbers tracking their northwestward range expansion over the past few decades? Who knows—but time and future seasons of Christmas Bird Counts will tell.

On a continuing less-than-positive note, numbers of Northern Bobwhite, American Kestrels, and Loggerhead Shrikes continue to decline in most regions. These are all species of hedgerows and shrub lands that require food negatively affected by pesticides—and are also affected by the decline of shrub land habitat across North America. Species of the shrub lands and grasslands of the world are among the most rapidly declining world-wide, and results from Christmas Bird Counts can help track how these species fare over the coming decades in the Americas.

Somewhat incredibly, for the fourth Christmas Bird Count season in a row there was a major flight of Snowy Owls southward during the 115^th CBC. It all started back in the 112^th Count, when there was a broad movement of Snowy Owls southward from the east coast to the west coast in southern Canada and the northern tier of states. In the next 113^th season, the Pacific Northwest bore the brunt of the invasion, with even higher numbers tallied on many CBCs than during the previous season. In the following 114^th CBC, the all-time record flight occurred in eastern North America, with the highest tallies ever recorded of these magnificent arctic predators on many CBCs, and birds found as far south as Florida and offshore to Bermuda. During the following summer of 2014, researchers in the arctic regions noted that yet again there was a high density of breeding Snowy Owls—this time much farther north and somewhat westward in Canada—with the result that a record Canadian season for Snowy Owls happened during the 115^th CBC, numbers even exceeding the flight from the 114^th Count. The Snowy Owl epicenter this past season was in south-central Ontario, on the north shores of the Great Lakes. The Kingston, Ontario CBC tallied 48 Snowy Owls, almost twice the number any CBC had during the record 114^th Count! We will find out in the upcoming 116^th Christmas Bird Count if there is another flight of Snowy Owls southward in the next season, which would make the fifth consecutive major flight. That may give indication of something significant changing in the Arctic environs.

From the 25 “Christmas Bird Censuses” that were conducted in December 1900, most of those covering city parks, the CBC program has grown to well over 2000 active 15-mile diameter circles across the United States and Canada. The area covered by those counts represents about 5.3% of the total landmass of the two countries, and that percentage is considerably greater when we look at the fact that most counts are done in the southern third of Canada and the lower 48 states. The results generated by Christmas Bird Count participants each season add to what has become a crucial long-term data set, used by conservationists and researchers on a weekly basis and generating a wealth of publications on the current and future status of birds across the hemisphere. We are entering a period of targeted growth for the CBC program, hoping to focus on areas where more coverage is most needed. Federal and tribal lands, the big empty spaces on the overall map, islands in the Caribbean, and of course much of South America all represent locations where more CBC coverage could be desirable. An “adopt a circle” program could also help re-start existing CBCs that have lapsed in coverage over time. Plenty of opportunity in the future awaits!

A Season of Changes

Despite all the interesting bird news about the 115^th CBC, this has been a season of considerable loss for the Christmas Bird Count program. Along with Dick Cannings’ departure as Canadian coordinator, you’ll read of other retirements and departures of long-standing compilers throughout the regional summaries. But in some ways the biggest hit was the death of Don Ekstrom, Audubon Science’s Program Manager in the Willow Grove, Pennsylvania office. Don was our phenomenally capable and talented behind-the-scenes person for many things Christmas Bird Count related, including the management of communications with compilers through the CBC Admin mailbox. Many of you have either spoken with him or emailed back and forth with him over the past 12 years. Don was the one who made things tick in the Science Office, and kept the CBC on track during many exceptionally busy times. He’s also in some ways the voice of the CBC, as it was he who produced and narrated all the instructional videos we have for compilers on the CBC website. His gentle demeanor and kind advice greatly helped many of us over the years, and though his voice lives on with the CBC the lack of his physical presence will be deeply felt.

Yes, 115 years is a long time, but a program like the Christmas Bird Count somehow brings out the best in people, and they stay involved for the long run. Remarkably we can still measure the entire existence of the program with the involvement of two ornithologists—Frank Chapman, who originated the program in 1900 and retired in 1934, and Chan Robbins, who started compiling in 1934 and still compiles and participates to this day. The old guard may someday move on, but up-and-coming young birders will fill the ranks. And so the tradition continues.