Reshaping the World with eBird Data

Cartograms provide a pleasing way to present geographical data. The idea is to redraw a map so that the relative sizes of its units (e.g. countries, states, counties, etc.) correspond to some measured quantity. A common example is a cartogram of population by country, in which the relative sizes of China and India become exaggerated, while large countries such as Russia and Canada shrink due to their small populations.

World population cartogram © Copyright Benjamin D. Hennig (Worldmapper Project) cc by [CC BY-SA 4.0 (, via Wikimedia Commons
Various repositories of cartograms can be found online; a good place to start is worldmapper. Details about the nuts and bolts follows at the end of this post.

Instead of human population, let’s consider global bird species distribution by country. The raw data needed to construct this image was pulled from eBird. The figure below shows the result, where several regions, such as the UK and Belgium, were broken into component states. While the size of the country represents the number of species reported, the color scheme is based on the number of eBird lists submitted, with lighter colors corresponding to fewer lists.

Cartogram of eBird species counts, by country. Darker colors correspond to higher numbers of lists submitted. Data is from early December, 2017.

The results are not surprising, but the map is striking nonetheless: Russia and Canada are barely perceptible, their landmasses reduced by a relative paucity of species; Central America bulges out and dwarfs the continental US; Australia shrinks in relation to the Indonesian island region; Northern Africa becomes compressed while the sub-Saharan countries bulk up; and northern South America shows its true dominance: little Ecuador is now practically as large as Brazil.

The color scheme illustrates how the majority of our worldwide birding efforts remain mostly in regions with less species diversity. It can also be viewed as an indicator of the infrastructure for birding that a given nation has, in some cases. Ghana, for example, has an adjusted size comparable to other West African countries, but its new size and color together show that it has developed into the most attractive destination in the region for global birders.

Making Cartograms

Constructing a cartogram requires an algorithm that will morph an existing map in such a way that the relative areas reflect the data. But a good cartogram must also produce an image where borders remain intact, and the component regions must retain enough of their original shape so that they are recognizable.

The process of making cartograms is not too difficult, but it isn’t simple either. There does not exist a single program that allows one to merely enter data, push a button, and have an image. Instead, several steps using different packages and data sources are required. The work here started with a query of eBird by-country data as of early December 2017, and the initial maps were downloaded from the Natural Earth site. The QGIS package was used to join the eBird data in with the map shapefile. The plots for global data were produced using ScapeToad to perform the morphing, using the highest quality (longest-running) setting. Finally QGIS was used to edit the ScapeToad output and produce the shading in the final cartogram.

Additional novel cartograms related to birding are in the works.

Thirty Years of eBird “Top 100” Data

The eBird site administered by the Cornell Lab of Ornithology was launched in 2002 and has arguably advanced birding more than any technology since binoculars. Beyond acting as a repository for one’s records, it affords many tools to explore the data submitted by tens of thousands of birders, while giving ornithologists an ever-growing data set that has no peer in other biological sciences.

Analyses of eBird data has so far tended to focus on distributions and migrational movements. But it can also give insights into the engagement of birders. Of interest here is the data from the “Top 100” page, which provides a snapshot of the efforts of the most active participants, and which can be tailored for specific geographical areas and/or time frames. For example, one can look at the highest total number of species reported, or lists submitted, for any year, and for any geographic region. With a goal of recording at least 2,500 species in 2018 while working full-time, a study of the Top 100 records seemed instructive. Specifically, records for the past 30 years were analyzed, with a focus on the maximum number of species (as opposed to maximum number of lists) for worldwide birding.

Consider the total number of species reported vs. year, as shown in Figure 1. The bright green points at 2002 indicate the start of eBird; the bluish data to the left consists of historical records that had to be entered by users at a later time, while the reddish data to the right features data added more in ‘real-time.’ Note that the 2015 record Big Year (6,042) of Noah Stryker is not shown here – it was removed as it is such a huge outlier – both statistically and in terms of the typical effort given by even the most prolific eBirders. Also, a word about the data for 2017: because the Top 100 data was queried on November 24, 2017, it represented an incomplete year – the specific values here for 2017 are an extrapolation of the counts as of late November, out through the rest of the year.

Figure 1. Last 30 years of species count data, for the Top 100 worldwide. Note that the 2015 record of 6,042 by N.Stryker is not shown in order to not compress the y-axis scale.

We see a clear, increasing trend in the number of species seen by the Top 100. In 1986, someone recording 1,000 species would have been the third most prolific eBirder, but in 2017, they would not even get into the Top 100. Also, after about 2005, there is a divergence in the average slopes of the top and bottom of the envelope of data – even as those in the lower portions of the Top 100 list are recording more birds every year, the handful of individuals within the top five or so are pushing the species totals up at an even faster rate. This almost certainly reflects a wider range of birding locales being explored.

A natural question at this point involves the makeup of the eBirding community reflected in this plot. The data was analyzed in terms of the number of years in which each individual appeared in these 30 Top 100 lists. There were a total of 22 eBirders that have been in the Top 100 sixteen or more times. Results for these 22 individuals alone are shown in Figure 2. Colors correspond to different eBirders.

Figure 2. Species vs. year for the 22 eBirders that were in the Top 100 at least sixteen of the 30 years spanned by the x-axis.

Figure 2 illustrates that the growing high species counts are not due to different, more prolific birders showing up more recently. Rather, it shows that the most continuously active eBirders are, on average, reporting more species every year.

Two other data sets were examined to see if trends were different. One set was based on highest species counts, but restricted to the United States only. The other set involved looking at the Top 100 worldwide, but using the total number of lists submitted instead of the species count as the determining factor for inclusion in the Top 100.

The median results for each case vs. year were determined and are shown in Figure 3. (The median captures an average sense of the Top 100 performance without being strongly influenced by any outliers.) The green line is for the original data set, where maximum species count is expected. The blue line is the same approach, but limited to the United States. The red line is for the case of highest numbers of lists, worldwide. Note that the blue curve does not include data for 2017 – it did not seem appropriate to extrapolate and project forward the numbers, given the lower ceiling on the total number of species possible in the USA as opposed to worldwide.

Figure 3. Median species vs. year for Top 100 data for three cases: The green line is worldwide lists maximizing species count. The blue line is for USA only. The red line is for worldwide lists but for maximum number of lists submitted.

In both the worldwide and US-only data, the number of species is increasing. Obviously the US-only curve will eventually ‘hit a wall’ before the worldwide data will. Meanwhile, the slope for the worldwide data has been ticking up constantly.

One might expect that the number of submitted lists that correspond to these increasingly larger species counts would show a proportional change. Species and lists counts do trend together, but not always at the same rate. Figure 4 shows the median number of species vs. the median number of lists, with a spline fit applied to show the general trend. Below 100 lists, and above, there is a dramatic change in the slope.

Figure 4. Median number of species vs. median number of lists for a year, for worldwide Top 100 (by species)

Figure 5 shows the same plot, but for the US-only Top 100. The results are qualitatively identical to what is seen in the global data.

Figure 5. Median number of species vs. median number of lists for a year, for US-only Top 100 (by species)

While in both cases, 100 lists roughly marks the inflection point, one should note the colors, which reflect the year: the change in slope occurs around 2005 in both cases. This suggests we look at the data for the median number of lists submitted vs. year, which is in Figure 6 below.

Figure 6. Median number of lists submitted. The red line is for worldwide lists but for maximum number of lists submitted. The blue line is for USA only maximizing species count. The green line is worldwide lists maximizing species count.

Clearly the changes in slope in Figures 4 and 5 are simply due to a very large increase in the median number of lists submitted by year, starting around 2005. This growth dramatically outpaces the increase in number of species reported. What caused the dramatic shifts in Figures 4 and 5? All of the data prior to 2002 had to be entered after-the-fact, often by hand, I imagine, and not everyone is going to be motivated to enter every note they had made in the field dating back x years. Maybe there was a tendency to consolidate lists? In any case, there is no question that among hard-core birders, there have been significantly more lists, and lists-per-species, on average, being submitted on a yearly basis since 2005. And this is true worldwide as well as in the US. Why didn’t the sudden shift in median number of lists submitted happen in 2002, when eBird began?  It seems reasonable to suppose that it took several years for “word to get out” and for birders to realize the utility of this powerful resource.

These trends should please the creators of eBird; not only is the army of observers growing, the efforts made by the most prolific members are steadily increasing on a yearly basis, garnering not just more species but more lists, and accelerating the size of the data set. It would be expected that this holds regardless of whether one is in a top-100 list or not. There is no reason to expect the trends to change anytime soon, although they will reach some asymptotic limits eventually. When, and at what values? It will be interesting to watch and see. I plan to revisit this at the end of 2019, and include some Top 100 lists at the U.S. county level also, to look at eBird’s impact on the hardcore birders that religiously monitor a given area as ooposed to trotting the globe.

A Global Big Working Year for Charity

The idea of a Global Big Working Year is to see as many species as possible between Jan 1 and Dec 31 without geographical constraint, but rather with a more pedestrian limitation: you have to work normal hours at your full-time day job, just like during any other year. (And no, if your full-time day job is being a professional birding guide, that doesn’t count.) In 2018 I will try to reach 2,500 species in this manner.

Is that a lot? A little? Is it a record, or not even close? For all I know this has been done before. (An official keeper of such records would certainly be welcome.) One can look at the eBird Top 100 for the world in order to get a feel for the numbers, but there are no details as to the time constraints at play. As of Nov 24th, 2017, there were seven individuals with more then 2,000 species recorded during the year. Based on their profiles, a few of these individuals appear to be active birding guides, so that wouldn’t fit with the GBWY criteria. In any case, 2,500 does not seem out of the question given sufficient travel on the weekends and vacations.

Without an official ‘record’ to try to break, I hope to make my 2018 GBWY mean more than just growing my life list at a healthy clip. I will pledge a fixed donation amount of at least $5 per species, for every species, over the year. That makes $12,500 or more my goal. Where is that money going to go? I plan to split it two ways, with half going for bird conservation efforts* and the other part going to research on blindness.

Maybe this is where I’d ask for others to contribute based on my result, or to do some kind of matching. That would be nice, but I wouldn’t ask for that. I can think of few things less interesting than birding or listing or doing anything, for that matter, vicariously. Instead, I’d rather challenge other birders to make a similar goal and pledge. Commit to some amount, any amount, per bird. Then pick a cause of your choice. Tell them what you are going to do, and do it. Tell other birders too.

This could even be done for just a day – such as the Cornell Lab of Ornithology global Big Day. They have a fundraiser based on the tally that their “Team Sapsucker” reaches during 24 hours – this is a great idea and it raises money for our common cause. Yet I can’t help but think that this could be augmented even more by having a Big Day Pledge fundraiser based on one’s own tally. You set the pledge level, you get the birds, and the accomplishment and the donation is a more personal event. Most importantly, it gets more involvement and more funds.

*Update Jan 6 2018: I’ve decided which birding cause I will support: Friends of Sax-Zim Bog. The timing on this is absolutely perfect, as they have just started a fundraising campaign for a “Big Half Year”

Birding in Ghana with Ashanti

We recently took a custom birding tour in Ghana and had a fantastic experience. We worked with Ahanti African Tours and they delivered an outstanding trip.

Claire and I have birding together for 24 years, mostly in the US, but abroad starting in 2002. Up to now, South America has been our most productive destination, but we have a new champion. Our nine days in West Africa netted us 282 species and 212 lifers. Ghana is a spectacular birding destination, and an overnight flight from NYC to Accra gets you here fairly painlessly from North America.

Our trip included the Shai Hills in the southeast, Kakum National Park and surrounding areas in the south, the Picathartes sites, and finally Mole National Park in the north. This gives an excellent sampling of rainforest and savanna habitats. Every new location that we visited brought new species; there was no duplication of effort.

Our guides, William, Ebenezer, and Kojo, went out of their way to make this a great tour. William in particular was one of those guides that has an uncanny ability to determine exactly where a bird has moved to after it has moved out of immediate visual range. I’ll never understand how this is done. They know their calls and songs intimately, and I tested them by recording as many vocalizations as I could and later checking them against xeno-canto. They didn’t misidentify anything.

We were especially impressed with their commitment to helping the local communities, such as the village of Bonkro, in addition to guiding. This is critical outreach, not only for improving the lives of their neighbors, but also in educating them about the importance of conservation and the protection of the priceless wildlife resources around them.

In Bonkro after seeing the Picathartes and making new friends. With driver/guide Kojo.

Our guides were able to accommodate for my vision issues, and because of their perseverance, I didn’t miss any birds. They also dealt with an unexpected challenge: on our final day, needing to get to the airport in Tamale for a flight to Accra, our vehicle broke down. This could have been a disaster but they managed to get us to the airport in time for our flight, and we made it back home as planned.

We are also happy to report that we didn’t have any digestive complaints during or after this tour. I wish I could say that about every tropical birding trip we have done. We were taken to good restaurants and hotels that always served very hot meals.

I cannot recommend this outfit highly enough, and I cannot think of a better introduction to West Africa birding. They offer trips in other locations as well, and we plan on using their services in Uganda at some point.

One final note; US citizens need a visa for Ghana, and it is highly recommended to pursue this through the Ghana consulate in Houston– it was fast and easy to get done. Reading about other traveler’s experiences indicated that other offices in the US were not always as efficient or consistent as they are in Houston.

Birding in the Tunnel

Retinitis Pigmentosa, or RP, is a degenerative, hereditary eye disease, and a miserable hand to draw at the table of genetic inheritance.

RP reduces, or outright destroys, peripheral vision, by attacking the rod photoreceptors which are distributed to the sides of the retina, away from the back of the eye, where the cones predominate. The cones provide detail, acuity and color perception, but they are limited to the center of the visual field. So the RP victim typically experiences tunnel vision, though in some cases it compromises the cones too, resulting in total blindness.

The rod cells that populate the outlying regions of the retina also provide night vision – a fact known to every amateur astronomer, for it makes possible the trick of averted vision: while looking at a particularly faint object, you are advised to direct your eye askew, letting the faint light of a distant galaxy of diffuse nebula fall upon the rods on the side of the eye. And indeed, what was only a faint smudge before will become a slightly brighter, more detailed smudge. With RP the rods don’t function, so low-light conditions are no-light conditions.

One might think that tunnel vision implies a view of blackness punctuated by a small aperture of visibility, like this:

Anyone in there?

This is not accurate. There isn’t any black. To see the black of the tunnel walls would be to see somethingThere just isn’t anything to see beyond the central core. And the brain isn’t content with the lack of information from the eyes, so it fills in. Sight is a joint effort of optics and image processing that builds a view of the external. In my experience, a better representation, though not perfect, is more like this:

Different. Not better.

In neither case can you discern the Many-colored Rush-tyrant to the lower right of the area of interest:

This is a photo I took during a trip to Argentina. I was having so much difficulty finding this little guy that I put the bins down and just starting taking photos in the general area where the guide pointed. Sometimes that is the only way to ‘see’ a bird.

The ruse makes it seem that the tunnel isn’t there. And if nothing happens or changes in the visual periphery, then the illusion is good. It’s as if you see everything. You can walk through your house, the details of which are well-known to your brain, without incident. But should the cat decide to crouch on the floor, the cat will be trod upon. Cats eventually learn to alter their behavior in a house with a blind person.

More difficult to navigate are public areas with people moving about without constraint, such as a busy airport. You seem to see everything, but then suddenly, a body materializes, as if beamed there by the fastest of teleporters, so close that a collision is barely (or not) avoided. It is startling, sometimes embarrassing, and potentially dangerous. (Airports are hell, as they are the natural habitat of rollerbags, those dreadful trailing extensions invariably in the no-sight zone. To those of us with reduced vision, they are a damned scourge.)

But the greatest frustrations for a birder involve birds, of course. We once attended something called “Jaegerfest” in Superior, Wisconsin. It was not a good experience. A ceaseless and hellish October wind came pouring off the Great Lake, watering the eyes and freezing the tears, while thousands of unidentifiable distant gulls wheeled in the poor light. From the assembled line of scope-wielding birders came the occasional cry of “Jaeger!” and instructions to look “at two o’clock, above of the water tower” or something similar. That anyone could then pick out one bird from that swarm was quite impressive, but beyond my abilities, so we left.

A nearby small lake provided a respite from the wind, and the waterfowl took advantage. Pintail, Green-winged Teal, Canvasback – amazing how they rode the waves on that blustery day in such a tight group, even as a man in chest waders clambered out towards them… what an idiot I am. I had trained my scope on this while a few bemused locals snickered behind me about the nice mixed flock of decoys I was studying.

We went back to Lake Superior, in time for the excitement of a Sabine’s Gull flying directly towards the shore, mixed among the copious and less interesting gulls. With RP, finding the unique gull flying amidst hundreds of others is no easier than finding a Greenlet up in the canopy. According to those around me, that Sabine’s Gull flew within tens of meters of the shore, banked, displayed its signature pied wing pattern in a most edifying and satisfactory manner, and then departed. I never saw it. The fellow next to me observed aloud that “No one can complain about that! What a great view!” Well I could have complained.

I used to keep my vision problems to myself, unwilling to be treated differently. But after the disbelieving guffaws of more than one guide and declarations such as “What? It’s right in front of you! How can you not see it?!” I decided to tell all my guides up front that I had a disability. Good guides account for this and remember, but others… not so much. After explaining my situation (in Spanish, no less) to a guide in the Ecuadorian Amazon, he was soon shouting at me, “Look with your binoculars! Look with your binoculars!” when a skittish Rusty-belted Tapaculo was moving below some nearby leaves in a very dark forest. As if that would have helped. I was lucky to have seen a flash of it with my unaided eyes.

Testing The Patience of Birding Guides Around the World – that’s my motto. Happily, most of them do a fine job, and more often than not I get the bird, because I’ve learned to be content if I get a recording of their call or song. However, I’ve been tempted to bring along some hardware that others can try on to see what it is like to bird in the tunnel:

Want to know what it is like to bird with RP? Get a Tusken Raider mask!


Global Big Years and Day Jobs

The recent accomplishments of Noah Stryker and Arjan Dwarshuis are impressive. Anyone that has traveled internationally for birding understands how grueling even a week or two can be. Uncomfortable overnight flights, jet-lag, immigration and visa paperwork, often barely adequate rooms (some with six- or eight-legged visitors), extreme heat, humidity or cold, and the joy of traveler’s diarrhea…would you endure any of this without the reward of seeing some spectacular birds? An entire year would be punishing indeed.

In spite of this, twelve months in worldwide pursuit of birds is a prospect that many of us would jump at. Not necessarily for the purpose of breaking what will be an increasingly formidable record – as gratifying as that would be. If that is one’s goal, the sooner done the better… as the record is broken again over time, it will reach a natural asymptotic limit, becoming more and more difficult to exceed. (Predicting this number is an interesting statistical question, which I plan to address later.)

The prospect of simply having an unencumbered year in which to bird is very seductive. For many of us, the necessity of attending to our day jobs renders such a extended project impossible. So what would be some next-best scenarios for attempting a ‘record’?

All birding contests, or anything that can be quantified with a record, must feature some kind of constraint. Even for a global big year, we have the arbitrary conditions of starting and stopping at a January 1st boundary. Big Year competitions based in North America feature geographical limitations based on arbitrary boundaries. A more recent, novel constraint is the ‘Green’ Big Year, which involves avoiding the use of fossil-fuels during travel.

A benefit to restricting a tally to a region such as North America is that it renders it possible to bird competitively through the year without having to abandon work – given the smaller area to cover and a total count expected to stay under 800 or so birds. What about a different tack? Let’s propose a contest that recognizes the biggest limitation that most of us have – the lack of free time. Let’s have a global big year for working stiffs category: a Global Big Working Year (GBWY), or a better name, if you’ve got one.

The rules might run as follows:

You have 365 days to tally your count, starting on Jan 1st. During that time, you must be working, or pretending to work, or otherwise not birding, for a minimum of 40 hours per week. You are free to bird on working days; before work, after work, over lunch or from your office window, but no more. Weekends and vacation days, of course, can feature as much birding as you can fit in, with no restrictions on geographical location.

Vacation time – how much time should be allowed? We can attempt a reasonable answer by looking at typical leave time around the world.

Based on this accounting, the median number of days off is 28. Combined with weekends, we come to 132 days that could be used fully for birding, and 233 days in which birding can only occur in concert with a normal, eight hour-per-day work schedule. If you have to burn a vacation day as part of your travel, then that counts against your allotment of 132 days, unless your travel is part of your work. (I checked with your bosses, and that’s what they said.)

Not everyone gets the same number of vacation days, so an adjusted total could be determined at the conclusion. The adjustment would increase your ‘score’ if you had less than 132 days free for birding. For example, if you had only 120 days of full birding due to work demands, and you recorded a total of 1,200 species, your adjusted score would be 1,320, which simply extrapolates your 10 bird/day average out to 132 days. (We need to put some lower limit on this, otherwise we could theoretically bird just one day, record 100 species, and then achieve a score of 13,200! A natural choice would involve the case of the poor sod that gets no vacation, leaving just 104 weekend days.)

So, if you used V vacation days and counted a total of N species, the adjusted score would be:

N * 132 / (104 + V)

How many birds could one expect to see under these conditions, assuming you could accumulate species at a comparable rate as the world record holders? In one year, Noah Stryker recorded 6,042 species based on Clements taxonomy (10,550 total), while Arjan Dwarshuis recorded 6,852 species using the IOC taxonomy (total of 10,672). Normalizing the Dwarshuis number for the Clements taxonomy, the value is 6,774, and that works out to between 18 and 19 species a day… 132 days of birding at this rate nets some 2,443 species. Adding the part-time birding that one can do during work days, a goal of 2,500 species, roughly one quarter of the birds on the planet, does not appear unattainable.

It is possible that this number has already been reached, but lacking a formal category for recognizing it, it won’t be widely known. If you’ve done such a GBWY, please leave a comment or a note. Such a category would appeal to many birders, and if we can have such as thing as a naked birding life list, then why not this?