Finally the 2018 AOS supplement is out! This is what many birders (I hope is not just me) wait for months to reveal what are the official “new species” to the list and what we have lost in terms of lumps of two species previously thought to be different. This issue has some interesting changes and some other changes that seem senseless and very redundant. But the appreciation of the actual changes can only be fully understood if we go deeper on the background of what happened here.
After reading word by word the new supplement I found out many of the actual changes have something in common. The use of a new technique to “ask the birds themselves” if they can recognized the call of an isolated population in where researchers never notice any difference. By using playback to test birds’ reactions to recordings of their relatives, observing whether or not they approached the speaker. As says Freeman (co-author of the research) to a note in the The Auk blogspot “these populations look the same—they have similar plumage and are similar in size and shape—but assuming that populations that sing differently tend not to interbreed, this means that species-level diversity in the Neotropics is underestimated.”
And sure it is underestimated, just by mixing the technique of the playback and then backing up with a bit of DNA tests they found out 12 new species for the neotropics. From all these new recognized species, one was found in Costa Rica and some of the other news also come thanks to this amazing research. Below I will explain in detail this and other noteworthy corrections you have to make to your bird book…
The resurrection of Scarlet-rumped Tanager.
So no more Passerines and Cherries Tanager… they did the playback experiment on this bird and found there were not enough discrimination on individuals of the pacific with the individuals of the Caribbean of Costa Rica to actually tell them apart as separate species. So after some more DNA experiments to reinforce the playback study they realized they are in fact the same species… which mean they were divided by the Talamanca mountain range only less than one million years ago (sorry, not enough to be a different species). So back to the old Scarlet-rumped Tanager as they decided to respect the original name… a much more appropriate name and one that brings back old memories about birdwatching in Costa Rica when I was younger.
"Is this a Cherrie's Tanager or Passerini's Tanager?" Who cares now... you wont hear this question anymore as they are all the same. Scarlet-rumped Tanager from Carara National Park area.
Welcome home Chiriqui Foliage-gleaner.
Back to the experiment of the playback again…. Freeman and Montgomery conducted the playback experiments on 15 territories of Buff-throated Foliage-gleaner in the pacific slope of Costa Rica and western Panama and 14 territories of Buff-throated Foliage-gleaner in the Caribbean slope of Costa Rica and Panama. Each playback experiment measured whether populations fail or not to be attracted by the song from the other population.
Populations of Buff-throated Foliage-gleaners from the Pacific and Caribbean slopes of Costa Rica respond strongly to local song but essentially ignore song from their relatives across the mountains. This suggests that vocal differences constitute a strong premating barrier to reproduction between these birds, and is consistent with the genetic data that indicates that, despite living quite close, these populations last shared a common ancestor around 3 million years ago and that is fair enough to do the opposite they did with the Cherries and Passerines tanagers and as conclusion we have a new endemic; Chiriqui Foliage-gleaner
Here you can hear a Buff-thorated Foliage-gleaner at Braulio Carrillo and here the call of the brand new endemic, Chiriqui Foliage-gleaner at Piedras Blancas. Please remember this subtle difference in your head as you will need it next time you hear one in La Cangreja or Macaw Lodge as the contact zones in intermountain valleys might be overlooked.
A brand new endemic for Costa Rica and western Panama. This Chiriqui Foliage-gleaner taken by Juan Diego in 2013 in the Rainforest Aerial Tram reserve near Jaco area was by then just another Buff-throated Foliage-gleaner.
Goodbye to our mystery Yellowthroat…
The playback experiment gave us a final “blow below the belt” with our mystery Yellowthroat.
For years a few resident Yellowthroats seen in the San Vito area were thought to be more similar to Masked Yellowthroat (Geothlypis aequinoctialis) than the expected Olive-crowned Yellowthroat (G. semiflava). The fact of having the whole isthmus of Panama dividing the two populations of Masked Yellowthroat and the differences in call and face pattern made all birders and ornithologist to claim this birds for years as a potential new species named Chiriqui Yellowthroat (G. chiriquensis). After the playback experiment it comes the surprise to show the bird in San Vito is not Chiriqui Yellowthroat but is not a Masked Yellowthroat either (here is where all the Costa Rican birders drop their jaws). Both genetics (a 2009 experiment with DNA) and song (including perception of song) show that the biogeographically proximate Caribbean and San Vito populations in Costa Rica are extremely similar; the conclusion is that the two should be called Olive-crowned Yellowthroat (G. semiflava). But now there is a funny note on reading how humans perceived bird calls to be different and how birds perceived. Even if the songs are very different (from a human perception) populations of Olive-crowned Yellowthroat from the Caribbean slope of Costa Rica responded strongly to songs of populations from San Vito, suggesting a lack of song-based reproductive isolation and by instance a change on the expected obvious conclusion that birds that sing differently would not interact to each other’s song. The final word is that if you don’t playback Yellowthroat calls in the field you would never guess it.
Turns out that our magical-mystery Chiriqui Yellowthroat is just another Olive-crowned Yellowthroat like this in the photo but with some plumage variation on the face... (nah... honestly I don't buy it).
A neotropical seedeater with french accent.
The White-collared Seedeater change its name to one more complicated to pronounce; Morelet’s Seedeater (Sporophila morelleti). As a split from Cinnamon-rumped Seedeater a new cool endemic that Mexico wins,only present in the Pacific slope and interior of Mexico. This two birds are very different and if you are into Mexican birds is a split you can see coming up, but why Morelets? Who is that Morelet? Well the subspecies morelleti was described by Bonaparte from specimens in the Paris Museum collected by “the French traveller Morelet” near Petén, Guatemala, in 1847. According to Jobling (2010), Pierre Marie Arthur Morelet (1809-1892) was a “French naturalist, artist, and collector in the Azores, Canary Islands, and tropical America.” He had a particular interest in drawing molluscs but apparently his interested quickly expanded as his surname is used in the English names of Morelet’s Crocodile (Crocodylus moreletii) and Morelet’s Tree Frog (Agalychnis moreletii), but apparently not a single bird species. The authors of this paper suggested keeping the name White-collared Seedeater will cause too much confusion if used in this sister species and considered giving priority to this old name originally suggested to be used in the subspecies by Ridgway’s but correcting the spelling to Morelet’s Seedeater (notice the latin name is misspelled but they decided to leave it like that… why? They said is to respect the mistake!... ornithologist moves in mysterious ways sometimes…).
The three new species and their range taken from the original SACC proposal by Mason et al. (2018).
The following changes have nothing to be with the playback experiments but in my opinion are also noteworthy as I love bird scientific names:
The “tree-riders” woodpeckers!
Hairy, Smoky-brown and Red-rumped woodpeckers will change their genus to Dryobates. A much more aptly Latin name that summarize a group of woodpeckers reasonably similar but in my opinion very different in many behavioral aspects. The spelling remind me a bit the famous genus of some neotropical posion dart frogs “Dendrobates”… and they actually mean something very similar in Greek. “Dryo” comes from druos "tree" and “bates” from bato "I mount". So using some of my imagination this guys can be literally translated as the “tree-riders”… way better than the old fashioned woodpecker name but of course the English name has no change in this new genus of woodpeckers.
The rise of a new Royal family…
And no, I am not talking about a child between princess Meghan and prince Harry… I am talking about a brand-new family in honor of the Royal Flycatcher called ONYCHORHYNCHIDAE… But, in Costa Rica, who is invited to this cool new family, well obviously the Royal Flycatcher but also some peasants with no crown. Like the Ruddy-tailed Flycatcher and both Myobious flycatchers (Black-tailed and Sulphur-rumped flycatchers)… no royal crown on any of this three but apparently they are closely related in DNA and believe it or not one of the reason to have their own family is because of their close relationship with Sharpbill! Yes, Sharpbill and Royal Flycatcher are relatives… I doubt they have ever seen face to face in their lives but well there you have it…
A brand new tropical queen rise its crest in the lowland rainforest of Carara National Park. The Royal Flycatcher now on her very own family. Photo by Juan Diego
Costa Rica lost an endemic genus (sad reactions only)!
Our sweet Cocos Island endemic and its endemic genus disappeared from the map. Cocos Flycatcher (Nesotriccus ridwayi) turns to be closely related with Mouse-colored Tyrannulet by instance changing its genus to the same of its closest cousin… making my imagination to fly and picture a Mouse-colored Tyrannulet standing in floating material in middle of the ocean for months until a few of these guys reached the Cocos Island. This is only my divagating thought but could actually happened there. I will never look at a Mouse-colored Tyrannulet the same way. So now Cocos Flycatcher is Phaeomyias ridgwayi and Costa Rica lost an endemic genus.
During a trip to the Cocos Island I spent hours watching this cute little endemic flycatcher and I had a feeling that the closest relative in mainland of the Cocos Flycatcher (right) was the Bran-colored Flycatcher (left). Do you think they look more similar now? But apparently I was wrong . Photos by Jorge Gabriel Campos and Juan Diego.
Finally, the orphaned Piprites found his family.
This is good news to me as my favorite nemesis bird in the world finally found his family! (this sounds like material for an episode of the Reality-TV show "Find My Family")… but certainly the Gray-headed Piprites have valid points to place him (and the other two members of its genera) in a brand new subfamily called “Pipritinae” among flycatchers. The genus Piprites has presented a taxonomic challenge for more than a century! But recent genetic studies indicate he is a flycatcher, by now.
The best photo I have seen of Gray-headed Piprites in Costa Rica (and pretty much one of the best pictures I have seen in the world) taken by Lev Frid near Turrialba.
Another fun name change that seems to be obvious coming up is the change on the English name of Red-breasted Blackbird to Red-breasted Meadowlark. So no more Blackbirds apart from the Melodious, Red-winged and the super rare Yellow-headed in Costa Rica.
Another lovely Meadowlark... Red-breasted Meadowlark taken by Juan Diego Vargas in Dos Brazos de Osa, Puntarenas.
And finally there is one taxonomic change I would like to mention... not because it worth a learning lesson or jaw dropping but more because it exemplified how silly these changes can seem for general public. In 2003 following a change that had been adopted by the British Ornithologists’ Union (1992) the English name of Rock Dove was changed to Rock Pigeon but just recently they realized that a few species of Australia are called Rock-Pigeons as their base name. So they have to go back AGAIN to Rock Dove to avoid the misunderstanding. As senseless as it seems but we all do mistakes and is fun to see when the mistakes are reversed but not before affecting everyone’s bird checklists.
The biggest fails in my opinion:
Yellow Warbler will still be just yellow...
This time we were very close to pass a much needed split of Yellow Warbler. As most readers will be aware there are a lot of “Yellow Warblers” with different amounts of red in the head. They are resident to Mangroves, Pacific Islands and Caribbean Islands. And go by different names… "Mangrove" Yellow Warbler, "Coco´s" Yellow Warbler, "Galapagos" Y. Warbler, among others. Well, the full split of all the insolated populations of this warbler failed! In summary because we still understand too little about their limits and how to split them correctly. But a formal proposal almost made it to make a small segregation of these warblers in two big groups. American and Tropical Yellow Warbler. Of course to make a division between resident and migratory. But unfortunately, it rebound again. Because “more research is need it” so keep calling them just Yellow Warbler by now. Even if they all sing different, have different breeding strategies and look quite differently.
Fig. 1. Bayesian phylogeny of yellow warblers based on combined mtDNA sequences. Green, North American migrant populations ‘aestiva’; yellow, West Indian golden ‘petechia’; red, Central and northern South America mangrove ‘erithachorides’. Plumage pattern corresponds to each subspecies based on plumage descriptions (Olson, 1980; Browning, 1994; Klein & Brown, 1994) and from museum skin collections. From Chaves et al. (2012).
The still poorly known "Cocos" Yellow Warbler... as you can see the amount of red on the crown is quite a field mark from our well known migratory "Northern" Yellow Warbler. This one taken by Juan Diego while guiding the last tour on the spectacular Cocos Island Endemic Adventure offered by Lifer Nature Tours.
Another new Ground Sparrow endemic to Costa Rica? Or not.
This one really hurt all Costa Rican hearts since is a proposal that comes from a young Costa Rican ornithologist and friend Luis Sandoval. He proposed to split White-eared Ground-Sparrow as a new endemic for Costa Rica. Three subspecies have been described based on plumage differences. One in Costa Rica between 500 and 2000 m; one from the northern highlands of Nicaragua above 500 meters and one from Chiapas, Mexico, to El Salvador. Historically the one in Costa Rica has sometimes been treated as a separate species based on plumage differences, size, and distribution. Although everything seems right on this (it almost went to penalties in the leagues of taxonomy) only had 4 positive votes vs. 6 negative votes on this proposal with the result of failing the split (but have to say that two of those votes were hesitating).
For most people on the committee the differences in the vocalizations don’t seem very strong, and plumage differences also seem slight. But one of the main arguments agaisnt was (AGAIN) the lack of new playback experiment we discussed at the begining of this post on all of the three populations! In my opinion the new "popularity" of this technique to show species limits and the lack of such an experiment on this particular proposal made it against our fellow Costa Rican ornithologist. We were close to two "arm-chair ticks" ground-sparrows in a row.
Barn Owl back to the barn.
They were sooo close to split Barn Owl into at least 4 species… only change for us was to add the word “American” in front of the name… not big deal to be honest but it didn’t pass anyway… for the same reason. “More research is need it” and they don’t want to have “half-way works”.
- T. alba (Western Barn Owl), 10 subspecies, widespread in Africa and Europe.
- T. furcata (American Barn Owl), 12 subspecies, widespread in North, Middle, and South America
-T. javanica (Eastern Barn Owl), 7 subspecies, distributed from south and southeast Asia to Australasia and southwestern Pacific
-T. deroepstorffi (Andaman Masked Owl), from the Andaman Islands
Who is next?
Don’t said I didn’t mentioned here, get psychologically prepared for what I think will be two of the major changes in the next supplement.
The split of “Golden-crowned Warbler” to change name in our area to Stripe-crowned Warbler. So if you were planning to ignore a Golden-crowned Warbler in Costa Rica because you have seen it in Brazil better dont do it.
During the same playback experiment these guys found that Orange-billed Sparrow populations respond strongly to local song, but, in most cases, ignore song from each other of another location this suggests that vocal differences constitute a strong premating barrier to reproduction between populations. The proposal is still in process but it will get to something soon.
My two cents...
But what is my main lesson learned in general with this new supplement for my every-day life as a specialized bird guide in Costa Rica and other latin American countries… Lots of people that like birds will see the use of playback to call a bird into the view completely unnecessary but for a bird guide that makes the living out of “birds seen” and in were “heard-only” can represent the difference between a success or fail on a search, the playback takes a serious different approach.
If you are on this shoes then you will understand that playback is a necessity for having good views of a lot of tropical birds (just as the hummingbird feeders are a necessity for a lot of bird photo guides… serious bird photographers know I am not lying here).
So I will say the moral of the fable here is that if every birder or bird guide using playback out there can leave a note on a public database (like eBird, iNaturalist or similar) about the response of the bird to a given song they were using that can be, potentially, a great help in future analysis of this kind. Maybe or maybe not... But certainly it will help way more than if you do nothing and just take a photo or "tick" the bird off your personal checklist and walk away. Even better if you can record it and upload to Macaulay Library or XenoCanto and make the note of the excellent response after playing back X or Y recording. Sometimes there are process that are hard to control but if you cannot defeat the problem try to see the positive aspect of it. And sure there are positive aspects to rescue when you are birding the remote tropical forest of Central or South America. So my shoutout here is: If you playback bird calls for your hobby at least “flag it” and release a bit of the guilt, leave a trace that can be follow for others looking for answers in a sea of questions and give a light about which bird they should focus more energy and time. "My two cents" on this.
Stay tuned for more…
Best regards from Costa Rica and get out there and listen some birds,
Some publications used for this post:
Del Hoyo, J. & Collar, N. (2017). Chiriqui Yellowthroat (Geothlypis chiriquensis). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved
from http://www.hbw.com/node/1344155 on 20 October 2017).
Escalante, P., Márquez-Valdelamar, L., De La Torre, P., Laclette, J.P. and Klicka, J., 2009. Evolutionary history of a prominent North American warbler clade: The Oporornis–Geothlypis complex. Molecular Phylogenetics and Evolution, 53(3), 668- 678.
Freeman, B. G., & Montgomery, G. A. 2017. Using song playback experiments to measure species recognition between geographically isolated populations: A comparison with acoustic trait analyses. The Auk 134(4), 857-870.
Mason, N. A., A. Olvera-Vital, I. J. Lovette, and A. G. Navarro- Sigu ̈enza. 2018. Hidden endemism, deep polyphyly, and repeated dispersal across the Isthmus of Tehuantepec: Diversification of the White-collared Seedeater complex (Thraupidae: Sporophila torqueola). Ecology and Evolution 8: 1867–1881.