ABA Checklist released


22 November, 2017

The ABA Checklist 8.0, which includes the approved Hawaiian list of species, has been published at http://listing.aba.org/aba-checklist/. The new checklist also resolves the question of the three mainland provisional species carried by the 2016 Big Year birders - all were approved!

Here then**, are the final scores of Big Year 2016 for 'Classic ABA' area and 'USA'. The Hawaiian species numbers as well as the 'New ABA' numbers are only hypothetical at this time; the ABA is presently deliberating over the question of the Hawaiian listings of 2016 Big Year birders on a provisional basis.



Classic ABA
*Hawaii
*New ABA
USA 
John Weigel
783
52
835
830
Olaf Danielson
778
51
829
825
Laura Keene
762
52
814
806
Christian Hagenlocher
752
0
752
749 


 *An ABA decision on the question of 2016 Big Year birders qualifying for inclusion of their Hawaiian sightings is pending.

** All figures are derived from the remarkable Big Year data sets of birding historian Joe Lill.

All years aren’t created equally

20 November, 2017

In these days of growing interest and participation in ABA Big Years, participants are becoming more strategic in their planning, and more focused on their results. It’s more or less become a ‘given’ that the serious contestant will likely tick all of the 673 ‘common’ species (Codes 1 & 2) from the ABA checklist by the dreaded end-of-year buzzer. Effectively, the real measure of success for the Big Year birder is the proportion of the 328 ‘coded’ species (Codes 3-5) that are ticked from that same checklist. Unfortunately for some, not all years will provide the same opportunities to rack up impressive rarities lists - irrespective of how much planning and effort is applied. Timing, it seems, can be an overriding factor in determining the outcome of a Big Year, as I’ll try to demonstrate below. What is less straightforward is answering the question of how to select that ‘perfect’ year to mount a Big Year campaign.

Possibly contributing to the difficulty in anticipating ‘good’ years for vagrant bird invasions, the historical pattern isn’t clear. A clarification of that pattern is needed before useful correlations with influencing factors - especially weather trends, can be found. My interest in this question of year-to-year variation in rare bird species numbers has recently become piqued while following the progress of the five birders currently racing around the ABA area (Yve, Ruben, Victor, Gaylee and Richard), having already chocked up impressive year-lists with more than a month left to go.

I wanted to measure the differences in rare bird species numbers in at least the most recent years. How does this year compare to last year? What about 2013, when Neil Hayward broke Sandy Komito’s long-standing record? To find out, I used the Species Maps section of the eBird Explore Data webpage https://ebird.org/ebird/map/ to extract all ABA coded species reports on a year-to-year basis. I acknowledge that going back only five years is not sufficient to draw a whole lot of conclusions – but I do intend to go back another five or ten years when I have the time. For the purposes of this current exercise, Hawaiian sightings are not considered.

In a perfect world, the number of coded species reported in the ABA area on eBird in a given year could be regarded as a sound reflection what’s going on in the field – e.g. if 2016 had 20% more rare species reported than did 2012, then it would be nice if we could assume that there were about 20% more rare bird species bouncing around in the ABA area in 2016. But it isn’t quite that simple. Other potential factors influencing the roughly linear rise in annual sightings over the past five years might include the ever-improving bird-reporting systems – with increasing use of eBird; the increasing interest in birding (resulting more birders stomping around out there locating unusual birds); the increasing strategically timed pelagic birding opportunities; and/or the improved coverage of the Alaskan outposts by dedicated birders and birding tours. Taxonomic changes present an additional factor to consider - at least in the longer term, with the net effect of all those splits and lumps gradually swelling the number of prospective coded bird possibilities. 

After crunching the eBird data, I’ve formulated two different ways of looking at the results. Table 1 provides a straight up comparison of the annual number of rare bird species reported at least once during the year on the eBird registry. More subjectively, I’ve also provided Table 2 in an attempt to differentiate between reported rarities that the serious Big Year birder might have had a good chance of sighting, as opposed to those reported species that couldn’t readily have been converted to ‘ticks’ by distant twitchers (e.g. one-day-wonders).

Table 1 (below) demonstrates a marked difference in the annual abundance of coded species reported on eBird over a five-year period. There were 151 rare bird species reported in 2016, compared to 126 species two years earlier - a whopping difference of 25 species. 2013 yielded a total of 130 species, which was still very low compared to 2016 and 2017, and yet Neil Hayward managed to break the longstanding Big Year record (even with a late start), largely by chasing every twitchable rarity on the eBird radar.


Table 1. Summary of the number of ‘coded’ bird species reported annually on eBird from 2012-2017*

2012
2013
2014
2015
2016
*2017
Code 3
73
75
74
77
78
77
Code 4
32
40
37
46
50
46
Code 5
11
15
15
21
22
26
 Code 6*
0
0
0
0
1
1
116
130
126
144
151
150

* 2017 figures are current only to time of writing - 18 November. Will update at end of year.

**Although previously considered ‘effectively extinct in the wild’, successful conservation measures have seen the California Condor rebound sufficiently to re-establish its ‘tickability’ for ABA birders in 2016.

From the perspective of the Big Year birder, I thought it might be an interesting exercise to categorize the rarity reports from each of the last five years on the necessarily subjective basis of ‘twitchability’. Of course, the total number of rare species reported in a given year is not the same as the number of rare species accessible by the year-lister. It doesn’t really help the twitcher when a Code 5 Eurasian Wryneck shows up on a no-access super-secret military installation, nor when an Atlantic Yellow-nosed Albatross is seen (only) on a single pelagic trip out of New York. At the other end of the accessibility spectrum, a Tufted Flycatcher with a history of almost daily sightings in a heavily-birded public place over a period of months is pretty much a ‘dead cert’, as the Australian birders would say.

For the sake of satisfying my own curiosity, I created a clearly unscientific but somewhat practical set of criteria to try to distinguish between incidences of ‘twitchable’ and ‘un-twitchable’ individual rare birds from many thousands of bird sightings reported on eBird. An inadequate definition of those criteria is provided further down the page.

Table 2. Number of rare bird species reported in each of the subject five years are separated into two groups – ‘twitchable’ and ‘untwitchable’.

2012
2013
2014
2015
2016
2017*
untwitchable
31
33
37
32
35
33
twitchable
85
97
89
112
116
117
total
116
130
126
144
151
150
In the process of assigning ‘twitchable’ vs ‘untwitchable’ status to the 328 coded species, I examined every eBird report for each species across each of the subject five years (you can see why I only went back five years, for now). To qualify for ‘twitchable’ status during a given year, a species must have presented the keen twitcher with at least one opportunity for a fair shot at encountering it. Typically, this meant that a bird needed to be sighted on at least one additional day, between two to four days after a previous sighting. Where sightings were confined to two back-to-back days, I’ve mostly erred on the ‘untwitchable’ side, though in reality, the ‘fly first and ask questions later’ twitcher will occasionally pull off a win in this scenario, at the cost of sleep and inflated last-minute flight costs. In practice, many birders rely upon their gut feelings about the ‘stickability’ of freshly reported birds, while others might invoke the ‘two-day’ or ‘three-day’ rule – wherein the bird needs to be relocated for a second, or perhaps third day before flights are booked. It’s a tricky challenge for Big Year birders that can be influenced by the extent of desperation in the air. The overly desperate or enthusiastic player can expend substantial effort and resources adopting the ‘fly first and ask questions later’ approach, only to accumulate a frustrating string of failures. On the other hand, Big Year contests can be won by the narrowest of margins, amplifying the value of the odd success generated by the ‘fly first’ approach.

For the purposes of this little study I’ve approached the twitchability issue for pelagic bird species a little bit differently. Coded species that typically show up at least four or five times per year off the California coast or the Atlantic Gulf Stream during the peak seasons are regarded as twitchable - even if it might require up to a half-dozen day trips to secure a sighting. Examples include Flesh-footed Shearwater, Bulwer’s Petrel Least Storm-petrel, and Craveri’s Murrelet, Great Skua, Trindade Petrel and Fea’s Petrel.

Due to the limitations of this study, there aren’t too many earth-shaking conclusions to be drawn about the cyclic nature of annual rare bird species numbers, let alone how that will affect the twitcher. But still, there appears to be strong year-to-year variation in the opportunities presented to the year-lister, suggesting that the Big Year birder would benefit from a better understanding of what makes a good year ‘good’, and how those conditions can be better predicted. Easy!