The answer to that thorny question is…
…when it becomes a gull! That’s when.
Anyone who knows me well, or has attended certain of our talks, will be well aware how I felt about the Turnicidae or buttonquails, being unceremoniously dumped into the Charadrii, our beloved waders. How I longed for the days when birds were classified by visual and behavioural traits and obvious close affinities. I was always puzzled by the inclusion of the Jacanadae i.e. jacanas (which resemble gallinules) and the Thinocoridae or seedsnipes (resembling grouse) in the seminal Shorebirds guide by Hayman, Marchant and Prater.
Later, and just as perplexingly the Pediononidae or Plains Wanderer and Chionidae, the two sheathbills were also added. I had read somewhere that the Charadrii is a taxonomic dumping ground – if you don’t know what it is, stick it in that particular suborder. It was certainly looking like that from my non-scientific perspective, which is where I come from. When the buttonquails were added I knew that disrespect to our waders was rife in the scientific world.
Well, recently a new study has shown that the buttonquails are not waders (I could have told them that) but are instead, gulls in the suborder Lari (I didn’t see that coming!). Bewildering though this is, I rejoiced, the buttonquails were gone.
Unseen and unfathomable science had deposited the buttonquails in our remit and then hooked them out again – hooray!
But it is worth remembering that surrounding every silver lining there is also a cloud; as I read on, my joy was short-lived.
I have always felt that pratincoles and coursers or Glareolidae were bone fide waders, despite the coursers being dry land birds and the pratincoles having such short legs that wading would be suicidal. But, this self same study showed that they too would migrate out of the Charadrii and into the Lari. However, there was worse to come. I discovered the Dromadidae, the single species family of Crab Plover was also to be removed to the Lari.
Now this surely is a classic wading bird, almost always seen wading on its wonderfully long and elegant legs, isn’t it? Admittedly it is anomalous in its breeding natural history when compared to the majority of waders; it nests in a burrow that it digs in the sand with its massive bill; single egg, white at that; non precocial chick, which is uniformly grey and white, not cryptic like other wader chicks and which needs to be fed (unsurprising since it resides at the end of a sandy tunnel). But with the adults resemblance to avocets and the bill like a thick-knee, the Crab Plover clearly fitted in near them, didn’t it? Apparently not. Its gone.
So, the number of waders in the world (formerly 257) has been reduced by 36 (18 buttonquails, 9 coursers, 8 pratincoles and the Crab Plover). This means that, if we count those that are extinct or thought to be extinct, the total now rests at 221.
On a personal level this means that from 186 species on my world wader list I drop to 172 species seen. From now on though, I will be referring to my success rate in terms of percentages and not actual numbers as that has risen from 72.5% of all species seen to 78%. If you then remove the 9 species I can’t possibly see, since they are extinct (or believed to be so), that percentage leaps to 81%.
Right, now, you science buffs, how about working your magic on the seedsnipes, sheathbills and the Plains Wanderer? I can live with Jacanas.
Wader Quest will be adopting these taxonomic changes with immediate effect, the wader directory on the website has already been updated.