Some analyses of 40-year bird count data in Central Massachusetts

1.

Two years ago, in a post with a cheesy title, I’d written about seeing cardinals frequently. I continue to come across them: it is still a thrill to see a sharp movement of red in the branches of trees, and to hear the bird’s distinctive calls. Inspired by these sightings, I find myself now drawn to other birds, mammals and insects that live in the wooded areas of New England.

On May 27th this year, I visited a tract of land preserved by the Massachusetts Audubon Society near Worcester: the Wachusetts Meadow Wildlife Sanctuary. There, I met naturalist Joe Choiniere. We talked for a while. Joe knew well the birds in the area -- details of their range, habitat, prevalence, appearance, calls etc. As the current property manager, he, like others before him, organizes a bird count each year at the meadow. I told him about my interest in looking at the data -- an interest that has grown ever since I began to teach probability and statistics. 

Joe said could share the data with me.  To observe how the data was collected, he also invited me to attend the count this year, on June 9th. It was a somewhat cloudy Sunday morning, but visibility was good. Around 10-15 people, most of them expert birders, broke into groups and went on different trails that wound through the hill forests, ponds and marshes of the sanctuary. I followed one group along the main dirt road. Each person carried a paper listing of all species and marked the numbers as soon as something was spotted. Close to 500 species of birds have been observed in Massachusetts, so one has to be a keen and experienced observer of birds to get the identifications right.

Late morning, everyone returned to a room in the Visitor’s Center. A coordinator called out the name of each species; the birders around the table responded with their counts, and a tally for 2013 obtained. This process remains the same each year. Minutes of the discussion are maintained, and journal published each year presents the tally. Variables such as the number of observers, weather and temperature can of course change somewhat, but the trails on which the counts are made have mostly remained the same. Most importantly, despite year to year variations, the 50-year duration means that some general inferences on population levels of particular species can be made. 

Joe sent me an Excel Spreadsheet with the count for all species at the meadow from 1964 to 2003 (the data for 2003-2013 is also available, but has not yet been entered in Excel). I started working with the data recently and made some preliminary graphs. In this post, I will illustrate, with examples, whether or not the annual bird count at Wachusetts Meadow tallies with other statewide trends. 

So let’s take a look at the cardinal count for 40 years since 1964, when the count first started at the meadow. The x-axis is the year. The y-axis is the number of cardinals observed by birders at Wachusetts Meadow.  We notice the variability from year to year (except in the early years when no cardinals were seen). But it’s pretty clear that there is an increase in the number of cardinals seen, even though there are still years when none are observed.

Note that the image is only of the male cardinal (somewhat sexist, you could say!); the female is more gray than red, but females are of course part of the count.

What do the statewide counts compiled by the Massachusetts Audubon tell us on the prevalence of cardinals? There are three such counts: the Bird Breeding Atlas (conducted from 1974-1979 and again from 2007-2012); the Bird Breeding Survey (an annual effort on specific roadways); and the Christmas Bird Count (a 114 year tradition that is kept going by enthusiastic citizens).  Trends in the cardinal population based on these counts can be seen here. Notice that all counts suggest either a "likely" or "strong" increase in the number of cardinals. This agrees with the graph above, based on the Wachusetts Meadow annual count.

2.

It is of course also possible that Wachusetts cardinal count may have only coincidentally agreed with other counts. So, for further validation, let’s look at the 40-year trend at Wachusetts for two other birds: the cliff swallow, and the house finch. 

I am fascinated by swallows: this July, I saw hundreds of rock swallows, their appearance similar to the above image, at the desolate ruins of the ancient city of Ani, along the river that separates Turkey from Armenia.

Sadly, for the cliff swallow we see a precipitous decline and counts have been zero for most of the 80s and 90s. This agrees with three statewide counts posted at the Massachusetts Audubon Society: they confirm a “strong decline” in numbers. The brief note says: “Today, the Cliff Swallow occupies less than half of the distribution it held in 1979. Loss of nesting structures, such as old barns and bridges, along with nesting competition from introduced House Sparrows are among the factors accounting for this restricted distribution.” 

For the house finch, we see no sightings at all until the 1980s. It turns out that the house finch was introduced into this region in the previous decade: “The introduced House Finch arrived in Massachusetts during the 1970s and never looked back. It can now be found living alongside humans over much of the state, and as a breeder it is nearly ubiquitous.” In the above figure, we don't notice high numbers in the years leading up to 2003, but the early years validate well with the available knowledge on house finches.

In both these cases, the Wachusetts Meadow trends again seem to match reasonably well with other statewide trends. Still, this is just preliminary evidence. Birders may be influenced by what they hear from others in their community or what they read in journals; during counts, they might unconsciously seek for a particular species or ignore others, thus introducing some “unnatural” variation. Yet, there is no way to completely escape such biases in a field study.

What impressed me most was the perseverance of anonymous individuals participating to keep such censuses alive all over the country. The comprehensive bird counts listed in the Massachusetts Audubon Society, all depend on the efforts of such individuals; the Christmas Bird Count has been going on for 114 years! 

Notes from Yellowstone and Wyoming -- Part 1

1.

The iconic Yellowstone National Park, the oldest in the US, established in 1872, is not easy to get to. If you don’t live in or close to the northeastern corner of Wyoming, you need either to drive from major cities like Denver, Salt-Lake City or Seattle – by no means a trivial drive -- or fly to two small airports, Bozeman (Montana) or Jackson (Wyoming). Despite its remote location, Yellowstone National Park gets 3.6 million visitors each year. Each day in the summer, as many as 10,000 tourists may visit the Old Faithful Visitor Center, named after the natural geyser -- one of dozens in the park -- which spews thousands of gallons of hot water every 90 minutes or so. Yellowstone is so crowded in the summer months that it can feel like a catered amusement park, rather than the genuine natural wonder it is.

For eight days in August 2012, we visited parts of the Greater Yellowstone region, shown below [map credit: yellowstonewiki.com]. Our flight departed from Hartford (Connecticut) at 7 pm; we reached Bozeman, Montana, with a stopover in Minneapolis, at 11 pm. From Bozeman, we drove to Yellowstone, where we spent two days, before leaving the national park and exploring some of the lesser known towns and regions in Wyoming.  Cody was the first stop on this route, reached through the Chief Joseph Scenic Highway that runs through the desolate Shoshone National Forest. Next, the town of Riverton and the Wind River Indian Reservation. In the last leg, we turned north to Grand Tetons, the other major national park in the area. Yellowstone is only 40 miles north of the Grand Tetons. From Yellowstone, it was a short ride back to Bozeman, Montana, through the town of West Yellowstone and Gallatin National Forest, for the return flight.

The descriptions below mostly follow the chronology of the trip.

2.

The Bozeman airport was just outside town, in Belgrade. We stayed at a Quality Inn nearby, managed by local employees. There was a Bible in the room: a reliable presence in most American hotels. But there was also, uniquely, a long note encased in a glass frame, placed on a desk. I will paraphrase the gist here: “We sincerely wish you a wonderful journey wherever you are headed in this beautiful region. We wish your presence is profitable for us; we also hope that if you are conducting business, like we are, that you have a most profitable time.” The message, brimming with cheer and goodwill, seemed a most natural merger of American evangelism and entrepreneurial zeal. It felt like a condensed version of the hyper-positive sermons the Houston evangelical preacher Joel Osteen delivers every Sunday on television.

In the morning, I had my first glimpse of the landscape around Bozeman. I’d imagined a very lush green setting, perhaps Alpine forests in close proximity. Instead, what I saw was not very different from the small towns in northern Arizona, Nevada, and New Mexico that I had traveled to as a graduate student: a mostly flat, dry and indistinct plain that stretched in all directions, allowing a very large sky, and ringed by bare brown mountains in the distance. 

Bozeman was a ten minute drive from the hotel. Naively, I had expected it to be a remote town with little to offer. Instead, Bozeman sprawled over an area that seemed large for its population of 37,000. The downtown had trendy restaurants, well-stocked bookshops, and a cooperative grocery selling local and organic food. The idea of a rugged, inhospitable West is only a decorative exterior in Bozeman. The coffee shops had plush seating and colorful interiors; and the well dressed young clientele, absorbed in their laptops, were probably students from the nearby Montana State University or urban backpackers on a break. Thinking back, I feel amused I did not spot a meditation or yoga center. But an easy google search reveals that there are in fact many in town.

There are two routes from Bozeman to Yellowstone National Park. One leads to the western entrance and the other through the northern – through Gardiner city. We took the latter. After downtown Bozeman, one could be forgiven for momentarily forgetting about the social conservatism of the region. Very soon, however, there were prominent signs on the freeway: “Life is a Beautiful Choice”. The radio shows were sympathetic to the Republican worldview. The grass had a beautiful tinge of yellow; the wildflowers by the roadside, also mostly yellow, were in full bloom. Otherwise the scenery was primary agricultural: grazing cattle and farms with mechanized equipment for irrigation, suggesting some sort of large scale ownership.

At the northern entrance to Yellowstone – commemorated by a historic old arch – a black SUV from Colorado proudly declared: “God bless our troops and especially our snipers.” How this message, aggressive in tone and spirit, could be reconciled the large cross of Christ that hung from the rearview mirror of the same car, remained a mystery.

3.

Most natural parks revolve around some startling visual feature or theme. The Grand Canyon National Park, for example, is about the wondrous shapes, depths, colors and textures that water and other natural forces have created in the brittle, dry and high Colorado Plateau. The same theme echoes, on a smaller but no less dramatic scale, through the national parks of southern and south-central Utah: Zion, Bryce, Arches, Capitol Reef, Canyonlands.

Yellowstone, however, is not just about one thing, though its active volcanic status – expressed through geysers, strange-colored (prismatic) springs, mud volcanoes, steaming vents – would be grand enough to draw crowds. There is a lot more. The Yellowstone River carves its own canyon (picture below), and provides startling and intimate views of waterfalls, sheer cliffs and rapids. And then there is the easily observed wildlife: bison, elk, bears, bighorn sheep, red foxes, pronghorn antelope, bald eagles, pelicans, ospreys, otters, trumpeter swans.  

This diverse visual bounty means that the five visitor’s centers, where the expensive lodging, dining and shopping options are, can feel like miniature cities in the summer. The large parking lots are constantly abuzz with people and cars, the constant opening and slamming of doors.

The suburban mall analogy isn’t far off the mark: for us humans, it is about shopping and consuming experiences that Nature has to offer. Whatever the cost, we are intent of capturing a slice for our own memories: by driving the 142 miles of paved roads in the park; getting too close to herds of bison or mother bears and cubs (as happened during my visit) for the petty reason that the posing tourists can be in the foreground of a photograph that can be proudly paraded on Facebook; using the expensive lodging and dining facilities, creating enormous quantities of trash in the process, a fact quickly forgotten as we bask in the glow of the odd environmentally sustainable practice that the parks and hotels promote.   

4.

During the summer, the National Park Service (NPS) hires 800 employees, who live within the boundaries of Yellowstone. The private firm, Xanterra Parks and Resorts, runs the lodging, fine dining and cafeterias for NPS, while the general stores are owned by Delaware North Companies Parks and Resort. These corporations have 3500 employees who live in inside the park, in shared dormitory-like settings. The employees, young and old, are hired from far flung states like Texas, but also abroad (Taiwan has a formal exchange program).

Xanterra claims to be an environmentally responsible corporation. It also has a presence in Grand Canyon, Death Valley, and Zion. Their 2011 sustainability report, accessible online, provides details about how they reduced absolute as well as adjusted greenhouse gas emissions over the last 10 years.

In true corporate style, the report is glossy and promotional, with scenic pictures distractingly placed next to the graphs and tables. The report essentially admits that the very idea of high end resort in a fragile natural places runs contrary to any notion of environmental protection. In this sense, it is honest. Corporations, the report says, make huge claims about sustainability to promote their public image; this façade is aptly called “greenwash”.

To its credit, the report does list some specifics: waste vegetable oil to partly power Xanterra activities; building a solar power generation facility in Death Valley National Park in California; soaps that are made of organic materials; and creating a store (the first of its kind, they claim) with a sustainability scorecard, to promote awareness. The vending machines smartly adjust themselves to peak and low usage periods, switching refrigeration on and off, thus minimizing unnecessary energy use. At Zion National Park, Xanterra has stopped the use of bottled water.  

In 2008, Xanterra was bought by Philip Anschutz, a Colorado-based billionaire whose empire includes businesses ranging from petroleum to entertainment. Anschutz is a cultural and social conservative, and, according to Wikipedia, was a major supporter of the George W Bush administration and his policies. When he bought Xanterra in 2008, however, he was, as this website claims, fully in favor of its sustainability initiatives. The question however remains: Can a billionaire involved with the petroleum industry and interested in furthering economic development, really be supportive of sustainability, or is he concerned more with the impression of sustainability, so that customers who use Xanterra feel less guilty about their travels – proud, even? The impression of sustainability is good for business, but sustainability itself is a more complex matter, and raises questions that we are afraid to face. 

One of Xanterra’s high end attractions within the park is the pricey Lake Yellowstone Hotel. The building is large and multistoried. Its yellow paint makes it look bland although the blandness could also be interpreted as a kind of minimalistic elegance. The lobby and lounge are spacious, have clean wood floors, small lamps attached to pillars, cushioned seating, a large piano, and a glass doors which provide a view of the Yellowstone Lake. When we got there in the afternoon, families and older couples, with drinks in their hands, were enjoying the view, as they waited for dinner.

An LCD television on a wall near the lobby provided a map and details of the local farms the food was sourced from. It was good to see this, but I wondered whether the benefits of local were incomparably overwhelmed by visitors like me, who had flown or driven from far flung places in the world.

5.

Driving north from Lake Yellowstone, you pass through Hayden Valley. The wide meadows and rolling hills here looked grand, and I felt it was principally because of the striking green and yellow hue of the grass, this last phase of the summer. Bison grazed in the valley along the winding path of the Yellowstone River. Occasionally there were clouds of dust as they indulged in mud baths, vigorously twisting their upside-down bodies, their legs flailing. Roads were routinely blocked by herds leisurely making their way across the road, from one meadow to another (these traffic halts have a name: bisonjams). Unlike elk, deer, bears, foxes, coyotes, and pronghorn antelopes, which are alert to the slightest movement, sensitive to the presence of people around them and therefore harder to see up close, bison seem to display a Zen-like dispassion to the flow of people or cars. This dispassion is an illusion of course: a roused bison can move fast and finish off a pesky, intrusive tourist with little fuss.

Indeed, bison are so easy to spot within the confines of Yellowstone that weary tourists, who have been in the park for a few days, declare with a touch of annoyance: “Oh, it’s only a bison.” 

How quickly one gets used to extraordinary sights! It’s easy to forget that this magnificient animal almost went extinct. In fact, it is not to be found in other wilderness areas in the country. Bison are raised in farms for their meat, but such herds cannot be considered wild. In all, there are about 4000 bison in Yellowstone. Once millions of them roamed the Great Plains. As America expanded westward, Plains tribes lost their lands; and new settlers hunted bison with rapacity and abandon. Their numbers at Yellowstone came down to an astonishing 23 – yes 23! -- at the end of the 19^th century. By pure chance, the thermally active region around Yellowstone did not lend itself easily to agriculture, and so was spared direct colonization by settlers. That did not stop poachers, however. The decline in numbers would have continued had it not been for a concerted, government backed effort at protecting bison and its habitat.   

6.

The somewhat less crowded Lamar Valley is in the northeast of Yellowstone. The landscape, dominated by scrub vegetation, is more rugged, and the silences mysterious. Bison herds are even more extensive, and are spread for miles and miles along the banks of Lamar River. Now and then, I spotted elusive pronghorn antelope grazing with bison. At trailheads, park rangers warned of recent bear activity.

Lamar is also where one is likely to see wolves. If the Bison’s near-extinction story is tragic, the Wolf’s is even more so: wolves were completely eliminated in Yellowstone, primarily due to their adversarial relationship with farmers. Efficient, large-scale agriculture is opposed to species diversity: anything that kills, directly or indirectly, what we eat (cattle or crops) must be eliminated to improve yields. Wolves kill cattle and therefore are on the wrong side of human interests. So, even as bison were protected in Yellowstone, wolves continued to be hunted. Unlike bison, wolves were not threatened on a global scale: there were other habitats where they still thrived. But in Greater Yellowstone, by the mid nineteenth century, they had disappeared.

In 1995, wolf packs were controversially reintroduced to Lamar Valley and Greater Yellowstone. They have a healthy presence in the region now. Their reinstatement provides a fascinating opportunity to quantify the impact a major predator’s absence or presence creates in the food chain.

This is what has been hypothesized: With wolves missing, elk numbers rose through the last century. Coyotes, rivals of wolves, also prospered. But streamside vegetation – willows, aspen – that elk consumed declined. Beavers, which depended on these plants, also declined. When the wolves returned, elk numbers reduced by half, coyote numbers are down as well. But beaver populations are back to healthy levels. Bears, meanwhile, have benefitted, since they can scavenge wolf kills easily. Scavenging birds – ravens, eagles, and magpies – have also more wolf-kill carcasses to feed on.

Whether observed increases and decreases in numbers of other species are chance correlations or whether the reintroduction of the wolf was indeed the principal cause is difficult to say with certainty. Nature is far too complex:  there exist plenty of other changes that happened in the same timeframe for the reintroduction experiment to have neat conclusions. Yet it is fascinating preliminary evidence on the interconnectedness of everything.     

A Fictional Conversation

For about a year, I've wanted to share and write about my newfound interest in religion, nature, animals, science, and all sorts of things that never interested me before. I tried the essay format, but so far I haven't quite succeeded in writing anything interesting. It takes time, I guess, to find the appropriate language, words and tone. It's always a work in progress. But here is an initial attempt to discuss religion and science, using two individuals. The two individuals are merely puppets to get some points across; it's very artificial for sure, but still felt better than an essay. Not sure how this is going to read -- but how does one know unless one tries?
 -----

“… but you still believe there is no conflict between religion and science?”

“It’s all about how you interpret it. It just depends on what you call ‘religion’.”

“To me, religion is belief in God, and that’s pretty clear cut.”

“Well, alright, let that be our definition of religion then: belief in God. It’s a problematic definition, but we can work with it.”

“Good. Now tell me how you can reconcile science with religion. To me science is about evidence and cultivating doubt, whereas belief in God is not.”

“Yes, that’s true. Science certainly provides more evidence than religion and also – if the scientists are honest – allows doubts and failures. You turn on the switch on and there is light – that’s proof that science works. The evidence is there in virtually all aspects of life, which we now take for granted…” 

“Whereas religion gets away with unverifiable claims: the presence of a soul, someone was enlightened thousands of years ago, or someone walked on water, or someone lifted a mountain…”

“But you cannot disprove these claims; these things could have happened. It would be unscientific to negate these possibilities outright, even if our current laws of physics suggest otherwise. A more apt way to phrase it would be to say that religious miracles, unlike everyday scientific miracles, cannot be demonstrated on a regular basis. You just take them on faith, which is really a blind faith, rather than saying: It could have happened but I cannot say anything for sure; there is no evidence.”

“Exactly! In science you have the burden of proof, whereas the burden of proof is not there in religion. One promotes skepticism, the other asks for blind belief no matter what. And then exploits that belief to create wars, divisions, ideologies. To me that’s an irreconcilable difference.”

“Well, science, if not practiced well, can also divide, create wars, ideologies and destruction. We humans are the problem, though we like to play the secular/scientific versus religious game. I have a more moderate view on the debate between science and religion. I think of it in terms of degrees of objectivity. In a relative sense, yes, science is more objective than religion, and there is no disputing that. But it would be incorrect to call science the ultimate truth or theory. We can instead call it the most objective truth we have, or what humans have collectively and gradually come up with, using the tools of logic and mathematics.”

“So there is something over and above?”

“I don’t know. Good science represents the limit – and it’s an ever expanding limit – of what humans can think of and explain. Beyond it, who knows what’s there. I simply don’t know. And that’s important: I don’t know – that space of not knowing is very important. Socrates said something about not knowing....” 

“I think he said: I know only that I know nothing…”

“Right. In my view, not knowing is where religion begins. Knowledge often leads to arrogance, but not knowing and being sincere and honest in accepting that you do not know is humility. This is the same humility that most of the world’s religions ask us to cultivate. But in general – and almost no one is immune from this – the more you know the more you think you can control, and you become egocentric and protective of your knowledge. In this aspect, science has a serious downside: the ability to know the laws of nature and exploit the natural world to suit human needs makes us feel supremely confident; we feel can achieve anything. We look only at what we have achieved, and feel tremendously proud as a species, but we ignore what we do not know at all.”

“But our lives are better…”

 “Materially better, yes, for now, but sooner or later, you run into a wall. Reality doesn’t quite function the way humans want. No amount of knowledge can capture the ever changing nature of reality. What the future has in store we have absolutely no idea. The universe and even events in our solar system may have some unpleasant surprises in store for us. Science is the effort to find answers, but no matter how deep you go, quantum mechanics, evolutionary theory and what not, you always reach a point where you do not know anymore. So you stop for a moment there and acknowledge, ‘Wow, this is too vast, too big and too complex, for my puny mind to understand.’ It’s the Great Unknown.”

“I understand that. But that’s still very different from belief in God…”

“Is it really? That’s why I said it is all in the interpretation. For me, the Great Unknown is what you can label, for the purposes of convenience, as God. I believe in this Great Unknown; I don’t know what it is, but it is there…”

“Well you know, you are sounding very mystical now!”

 “Why not! A scientific pursuit is really a mystical pursuit. I start with the feeling, ‘I want to know’ and you do get to know more, and you are able to explain more. It is a great feeling – you can compare it to the religious joy that a pilgrim or a monk or a yogi might feel. Einstein’s theories of relativity are aesthetically beautiful theories – they say it is the most elegant use of mathematics to show the intertwined nature of space and time. Darwin’s ideas make you feel connected to every living creature in earth – by his thesis, the animals and birds you see around you are your cousins! That promotes a wonderful feeling of unity! At the same time, there still are unanswered questions and new questions, and you realize you can’t know everything. That does not mean you stop – you can be thankful for the knowledge you have and you can keep the search going – but the illusion that you will know all begins to go away.”

 “Alright. Your ‘religion’ -- if you can call it that -- is quite different. Something like a poetic impulse with scientific bits thrown in. I don't have an issue with it. My main issue is with the monotheistic faiths that claim that there is a Creator, or that the world has been intelligently designed. I feel these faiths are quite arrogant – they prescribe that there is only one way and no other way, and in doing so cause all sorts of problems.”

 “Saying that there is only one way and no other way implies that the person who is making that very strong claim has complete knowledge – wouldn’t that be the opposite of humility? Is it possible for someone to claim, with tremendous sincerity and honesty and without a trace of doubt, that there is only one way to God and that all other ways lead to hell? And as for the existence of a Creator, one cannot reject the possibility: no one can disprove something that so far not been seen. But it does not matter anyway. Whether a Creator exists or not is irrelevant; the Creation exists – by that I mean this universe, this earth we live in, the sun, the moon, our senses and our thoughts which allow us to experience the world, they all exist, or at least seem to be vivid and real to us. That’s all that matters, and that itself is a miracle of sorts. This is actually an amazing fact: the Creation is everywhere and all around us, this table here that my eyes allow me to see, this chair whose solidity I can feel, this fruit that I can smell and taste! It makes you ask the question: What is all this? That itself can impart a sense of wonder.”