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

All years aren’t created equally
20 November

In these days of growing interest in ABA Big Years, participants are becoming more strategic in their planning, and more focused on their results. It’s a ‘given’ that the serious contestant is likely to tick all of the 673 ‘common’ species (Codes 1 & 2) from the ABA checklist by the dreaded end-of-year buzzer. The real measure of success for the big year birder is what proportion of the ‘coded’ species (Codes 3-5) are ticked from that same checklist. Unfortunately for some contestants, not all years will provide equally generous 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 an ABA big year, as I’ll attempt to demonstrate below. What remains less clear is how to select that ‘perfect’ year to mount a big year campaign.

Part of the reason it's not easy - if even possible, to predict a ‘good’ year for vagrant bird invasions, is the lack of concise historical information to start with. A clarification of past trends would help identify potential correlations with climatic trends such as to El Nino/La Nina events. My interest in examining the year-to-year variation in rare bird species numbers has recently increased while following the progress of the five 2017 big year (Yve, Ruben, Victor, Gaylee and Richard). All five have already chocked up impressive year-lists with more than a month still to go – and December has historically been a peak period for rare bird discoveries within the ABA area.

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 exercise, Hawaiian sightings are not considered.

In a perfect world, the number of coded species reported 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 the ABA area in 2016. But it isn’t quite that simple. Other factors potentially 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, hopefully flushing unusual birds); increased strategically-timed pelagic birding opportunities; and improved coverage of the Alaskan outposts by dedicated birders and birding tours (though it seems numbers of birders venturing to the islands swell on years following ‘good’ years, and wane on the heels of relatively bad ones). Taxonomic changes present an additional consideration - 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 numbers, I formulated two different interpretations of the data. 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. Additionally, and necessarily more subjectively, I’ve made an attempt to differentiate between reported rarities that the serious Big Year birder might have had a good chance of sighting at some time during the year, as opposed to those reported species that couldn’t readily have been converted to ‘ticks’ by distant twitchers on any occasion (e.g. one-day-wonders).

Table 1 (below) shows a marked difference in the annual abundance of coded species reported on eBird over a five-year period. For example, there were 151 rare bird species reported in 2016, compared to 126 species just two years earlier - a whopping difference of 25. Before that, 2013 yielded a total of 130 species - 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.

As suggested earlier, I thought it might be an interesting exercise (at least to my fellow big year birders of recent years) to categorize the rarity reports from each of the last five years on the subjective basis of ‘twitchability’. Obviously, not all reported rare birds can be subsequently chased down by other birders. Many reported birds are observed only fleetingly - perhaps with a single sighting by a single birder, hence, the total number of rare species reported in a given year is not the same as the number of rare species accessible to the year-lister. It doesn’t really help the twitcher if a Code 5 Eurasian Wryneck shows up on a no-access super-paranoid military installation, nor when an Atlantic Yellow-nosed Albatross is seen (only) on a single pelagic trip out of New York. At the other extreme of the ‘twitchability’ scale, a Tufted Flycatcher with a months-long history of almost daily sightings in a heavily-birded public place, 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’ versus ‘un-twitchable’ individual rare birds, by screening thousands of eBird reports generated from 2012-17. 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
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 excercise 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 of these include Flesh-footed Shearwater, Bulwer’s Petrel, Least Storm-petrel, and Craveri’s Murrelet on the west coast; and Great Skua, Trindade Petrel and Fea’s Petrel on the east coast.

Due to the limitations of this excercise, there aren’t any substantial conclusions to be drawn about the cyclic nature of annual rare bird species numbers, let alone how these might affect the twitcher. But at the least, there clearly is 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!