Saturday, November 26, 2016

A Record-breaking day!

And for a second year in a row, a world birder visits our isthmus in his quest to record the largest number of birds species in a year.  Arjan Dwarshius' attempt to break the world's big year record of 6042 species recorded in a year, set by Noah Strycker just 11 months ago, was about to make history!  After spending his first day in Panama last November 3rd, Arjan was just 11 birds away of the record!  This was not coincidence... Arjan and, his uncle Fred, chose the local advantage to make the most of their time in our country... they were guided by Guido Berguido who runs Advantage Tours and who is the head of the local NGO ADOPTA Panama Rainforest... and also an old, good friend of mine!  Also joining them was another friend of mine, birder extraordinaire and, since recently, an excellent, independent birding guide Ismael "Nando" Quiroz.
Elfin forest at Cerro Jefe, above Cerro Azul (file photo)
I took the late night bus from Penonome town (about two hours from Panama City), where I was resting with my family during the holidays (yes, the first days of November are holidays in Panama), in order to join the group in the record-breaking day!  Very early the next day, we headed to the gated community of Cerro Azul in the foothills to the east of Panama City, and headed directly to the upper slopes of Cerro Jefe and its stunning elfin forest, home of many range-restricted birds.  The day started quite low, but with some new year-birds for Arjan.  At the Vistamares trail we crossed a mixed flock with Shining and Green Honeycreepers, Rufous-winged, Emerald, Speckled and Black-and-yellow Tanagers, migrant Red-eyed Vireos, Tawny-capped, Fulvous-vented and White-vented Euphonias, Paltry Tyrannulets and White-ruffed Manakins, among others.
Black-and-Yellow Tanager (male)
After a while, Guido managed to attract an endemic Stripe-cheeked Woodpecker allowing scoped views... but the desired Black-crowned Pittasoma refused to show up...  but a pair of handsome Yellow-eared Toucanets were a nice consolation price instead.  Eventually, we managed to find 10 new birds for Arjan's list.  Year-bird 6042 was the Black-eared Wood-Quail that we actually managed to see thanks to Nando's advice (it was a life bird for me; although I have heard it several times previously).  After that, the activity dropped sharply... and we decided to have lunch before heading to Calle Maipo trail.
Yellow-eared Toucanet (male)
At Maipo, the record-breaking bird arrived quite unexpectedly when a Tody Motmot (very rare in the area) responded to a recorded call played by Guido... we tried hard to see the bird but it turned out to be very shy... but we saw a pair of Crimson-bellied Woodpecker that were Panama lifers for me as well (not a new year-bird for Arjan of course).  After realizing that we were not going to see the bird, we accepted that the record-breaking species was a heard-only record... of course, lots of high-fives, big smiles and congratulations continued!  Uncle Fred surprised all of us (including Arjan) when he opened a Champaign bottle and a nice banner to celebrate the moment... I'm impressed of his organization!
He did it!
We ended the day at the-now-famous Finca Bayano, were we managed to find the Long-billed Dowitchers reported earlier in the season... they were new year-birds for him, as well as three other species in spite of the short time we spent there.  And in spite of the short time I shared with Arjan, I can tell that he is passionate about birds and birding... he really seemed to be enjoying each little brown job that, desperately, we were pointing to him hoping it to be a new year-bird for him... but what can you show to a man that already has seen more than 60% of the extant birds of the world! I recommend you to track his progress HERE... the numbers are just amazing!  Not only that, remember that he is birding as a fundraiser for the BirdLife Preventing Extinctions Programme , so enter the webpage and make a donation!  I had to said good bye after leaving Finca Bayano... a long journey back with my family was awaiting me.  He spent five more days in Panama, watching amazing birds in Chucanti, Nusagandi, Yaviza, Aligandi and even right here in Panama City before taking his flight to Costa Rica.  Check this POST and you'll see that he is VERY lucky as well! 
FAREWELL, MY FRIEND.... I know 7000 birds for this year is plausible!

Tuesday, November 22, 2016

ID of Dowitchers in Panama

Until some time ago, identifying wintering dowitchers in Panama was pretty straight forward... only Short-billed Dowitchers were expected in this country at any habitat since Long-billed Dowitcher is very rare and expected to winter south only to northern Central America; however, some records exist from Panama.  The problem is precisely our assumption that any dowitcher seen in Panama is a Short-billed Dowitcher, and so far the most important publications on birds of Panama have a cautionary note that both status and distribution of Long-billed Dowitcher in Panama are uncertain due to difficulty of identification.  Nonetheless, more and more Long-billed Dowitchers have been recorded in Panama, specially this fall with great numbers recorded already.  How good are you identifying dowitchers?  Try with this bird:
Dowitcher sp. Panama Viejo, Panama. November 13th, 2016
Dowitcher sp. Panama Viejo, Panama. November 13th, 2016
I took the above pictures in the coastal mudflats of Panama Viejo, in Panama City.  As usual, I assumed it was a silent Short-billed Dowitcher in almost complete basic plumage (some retained alternate feathers in the back and scapulars).  The best way to separate both species is by voice... but if your bird is silent (as it usually happens in Panama), what field marks are you going to look for? The first thing to do when you try to ID these birds is aging them, because it is easier to separate juveniles of both species than adults in basic (non-breeding) plumage.  With our country well into the usual winter range of Short-billed Dowitchers (and way to the south of that of Long-billed Dowitchers), we will certainly find juvenile birds molting into basic plumage.  It doesn't matter how advanced in molt they could be, since most of them retain at least some juvenile feathers until January (including the characteristics tertials feathers).  In general, juvenile Short-billed Dowitchers have dark-brown upperparts feathers with broad golden-buff fringes and variable internal markings, particularly in the tertials (given them the typical "tiger-striped" look), and dark brown crowns that contrast with the white superciliums.   Underparts whitish with buff-brown wash, slightly brown-streaked upper breast, sparse spotting and barring on flanks and undertail coverts.
Juvenile Short-billed Dowitcher. Juan Diaz, Panama. November 4th, 2010.  Dark crown, retained juvenile greater coverts, diagnostic retained "tiger-striped" tertial feather.
Juvenile Short-billed Dowitcher. Panama Viejo, Panama. November 12th, 2016.  Dark crown, retained juvenile greater coverts and scapulars, diagnostic retained "tiger-striped" tertial feather.  Also notice shape and structural differences (see text).
Juvenile Long-billed Dowitchers are darker above, with only thinner and duller buff fringes to scapular and tertial feathers, the latter almost lacking any internal mark.  Juvenal greater coverts are uniform gray.  Compared to Short-billed Dowitchers, Long-billeds' crown is grayer with slightly less contrast with the rest of the plumage.  The underparts are very similar to those of juvenile Short-billed Dowitcher.
Juvenile Long-billed Dowitchers. Finca Bayano, Panama. November 10th, 2016.  Gray crown, retained scapular feathers with just buff fringes (almost no internal markings) and retained tertial feathers with just thin buffy fringe.
Our mystery bird lack any retained juvenile-patterned feather, making it an adult bird.  Separating basic plumaged birds of these two species used to be considered an impossible task... a task that we have to deal with in Panama on a daily basis, specially now that we know that Long-billed Dowitcher can occur in great numbers as well.  Several papers on identification can be found on-line.  Most of them describe plumage differences, but differences in structure, shape and habitat are useful too, although structure and shape differences varies among populations, age and sex, even within a same species.   I'll illustrate some of these differences with the next two photos of an adult Long-billed Dowitcher and a juvenile Short-billed Dowitcher (same photo posted above):
Adult Long-billed Dowitchers. Finca Bayano, Panama. November 10th, 2016.  Straight, thin-based bill, slight indentation at the back, big-chested look with attenuated rear, wingtips doesn't reach the tail tip
Juvenile Short-billed Dowitcher. Panama Viejo, Panama. November 12th, 2016.  Notice bill shape, more oval-shaped bodywith no indentation at the back, rotund rear and wingtips reaching tip of the tail.
The length of the bill (as their name suggests) is useful to differentiate females Long-billeds and males Short-billeds.  But more important, notice the difference in shape, with Long-billed Dowitchers having very straight bills while Short-billed Dowitcher shows a slightly downcurved tip, that looks kinked, as if the bird had left the tip of the beak trapped when a door was closed.  Also, bill of Short-billed Dowitcher tend to be more wide-based and blunt-tipped than the thin-based and pointed bill of Long-billed Dowitcher.  Body shape also differ, with Long-billed Dowitcher having a deep-chested look and shorter wings, thus attenuating the rear of the bird that often look with cocked tail; different to the more oval-shaped and horizontally oriented body shape of Short-billed Dowitcher that have longer wings, with wingtips usually reaching the tail tip or beyond (thus looking with more rotund rear).  Long-billed Dowitchers are also longer legged, an useful field mark to detect lonely birds among a flock of Short-billed Dowitchers.  Again, all of these structural differences varies depending on sex, age and population, and not only on species, but can be useful when inspecting a distant flock of dowitchers or under bad light conditions to see plumage field marks.
Adult Long-billed Dowitchers (ID by voice). Las Macanas marsh, Herrera. January 28th, 2011.  Notice bill length and shape
One field mark that is proving to be quite reliable is the loral angle given a direct profile view.  This is the angle between an imaginary extension of the gape of the bill toward the back of the head and the line connecting the gape of the bill with the center of the bird's iris.  A diagram probably explains it better:
Close-ups of previously posted photos.  Long-billed Dowitcher, above, showing a more acute (smaller) loral angle than Short-billed Dowitcher (below)
This angle reflects differences in facial expression, forehead shape and relative position of the eye between these two species.  As you c an see, Long-billed Dowitchers have more acute (smaller) loral angles than Short-billed Dowitcher.  Ok.  I have to admit that all the differences mentioned so far are quite difficult to asses in the field, but take into consideration that you need several field marks, instead of an unique and definitive feature, to ID correctly basic-plumaged dowitchers in Panama.  Once you are used to these differences, then you can compare the plumages of these both species.  Starting with the most common, basic adult Short-billed Dowitcher tend to be paler than Long-billeds, with patched gray breast that doesn't contrast strongly with the white belly and setting a more conspicuous white throat, and spotted and chevroned (instead of barred) flanks that are paler than in Long-billed Dowitcher.
Adult Short-billed Dowitchers. Panama Viejo, Panama. November 4th, 2010.  Pale and patched gray breast making little contrast with belly, pale and plain backs, chevroned (not evidently barred) flanks.  Notice also body and bill shapes.
Adult Long-billed Dowitcher. Finca Bayano, Panama. November 10th, 2016. Dark and solid gray breast contrasting with belly, barred and contrasting dark flanks, inconspicuous white on throat.
Notice that the back feathers in Long-billed Dowitcher have dark centers explaining the uniformly scaled and darker look than in Short-billed Dowitchers (with plainer, paler backs).  Also notice the white-fringed coverts feathers in Short-billed Dowitcher (vs brown-fringed in Long-billed Dowitcher).  At flight, the lesser coverts in the underwing of Long-billed Dowitchers are white with no bars (barred in Short-billeds), a field mark seldom noticed.
Adult Long-billed Dowitcher. Finca Bayano, Panama. November1st, 2016. White lesser underwing coverts diagnostic. 
The tail pattern is partially useful in Panama where the three subspecies of Short-billed Dowitcher occur... both caurinus and hendersoni show variability in tail feather patterns.   Now, back to our mystery bird:
Dowitcher sp. Panama Viejo, Panama. November 13th, 2016
Dowitcher sp. Panama Viejo, Panama. November 13th, 2016
When I reviewed the photos, it was the tail feathers pattern that caught my attention.  It seemed that this bird had wider black bars than white ones, consistent with Long-billed Dowitcher; however, as I mentioned earlier, it doesn't seem to be useful in Panama as a unique field mark to ID this bird.  Other field marks are covert feathers fringed in white, patched gray breast, pale flanks and back (although it looks faintly scaled), white throat and open loral angle... all of them suggestive of Short-billed Dowitcher.  Other structural differences are not evident in these photos (except long wingtips).  Last clue is habitat.  This bird was recorded in coastal mudflats, an habitat where Long-billed Dowitchers have never been recorded in Panama; however, take into consideration that the fresh water/salt water habitat preferences described for Long-billed and Short-billed Dowitcher is vague... Short-billed is fairly common in fresh water habitats inland in Panama, while there is at least one record of Long-billed Dowitchers in coastal saltflats (as in Aguadulce, central Panama).
Adults Short-billed Dowitchers. Juan Diaz, Panama. October 8th, 2010
I'm not discussing differences in alternate plumage because it is seen for a short period of time in Panama, but I encourage you to study about them in order to adequately document the different populations that winters in Panama.  Take these alternate plumaged hendersoni Short-billed Dowitchers for example:
Alternate adults Short-billed Dowitchers (ssp. hendersoni). Aguadulce salinas, Cocle. August 5th, 2016.
Well, there is a lot to study and to reveal about these two species in Panama... is time to grab your bins and to get some dowitchers to ID!
Literature consulted:
1. Ridgely R, Gwynne J. A guide to the birds of Panama. Princeton University Press; 1989.
2. Chandler RJ. Dowitcher identification and ageing. A photographic review. Brit Birds 1998; 91: 93-106.
3. Lee C, Birch A. Advances in the field identification of North American dowitchers. Birding 2006; sept/oct: 34-42.
4. Angehr G, Dean R. The birds of Panama. A field guide. Zona Tropical; 2010.
4. Karlson K. kevin's id tips: Long-billed and Short-billed Dowitchers. Available at 

Tuesday, November 1, 2016

Bird of the Month: Hudsonian Godwit

The Hudsonian Godwit (Limosa haemastica) is an elegant wader of long legs and upturned long bill that breeds locally in subarctic Alaska and Canada (east to Hudson Bay) and winters in southern South America on both coast, but mainly along the Atlantic coast.  Their migration routes not usually include Central America nor Panama; that is why they are extremely rare here.
Hudsonian Godwit
So far, there are only two published records: a basic-plumaged bird at the Caribbean side of former Canal Area in October, 1983 (photographed) and three birds seen at flight (from an airplane) on the coast 20 km east of Panama City in September, 1997.  A more recent unconfirmed report (January 2010) of a basic-plumaged individual appears in Xenornis by my friend Venicio Wilson.  This season, two juveniles were found by Euclides Campos on October 25th, 2016 in Finca Bayano, a rice farm 40 km east of Panama City.  So far, they have been re-located on October 29th and today, November 1st, at the same site (and where I took all the photos shown in this post).
Hudsonian Godwit showing tail pattern
These birds were actively feeding by probing the mud with their long bills in typical habitat.  In other parts, these birds are found in mudflats and coastal areas as well.  The scaled back and warm tones of these birds make them juveniles; adults in basic plumage are grayer overall.  However, at all ages these birds exhibit black tails with white rumps (as seen in the preening bird above) and dark wing linings and narrow white wing stripe in flight, as seen in the blurry bird below.
Hudsonian Godwits (notice under wing pattern)
Despite its delicate appearance, these birds are powerful creatures that make nonstop flights over the open sea for several days in order to reach their wintering grounds.  Having a pair refueling in Panama to continue its journey is a special event... one that nobody knows when it will repeat.  For these, and many other reasons is why we chose the Hudsonian Godwit as our Bird of the Month!
Hudsonian Godwits
Literature consulted:
1.  Ridgely R, Gwynne J. A Guide to the Birds of Panama. Princeton University Press: 1989.
2.  Angehr G, Engleman D, Engleman L. Where to find birds in Panama. Editora Novo Art, 2006.
3.  Angehr G, Dean R. The Birds of Panama. A Field Guide. Zona Tropical: 2010.
4. Van Gils J, Wiersma P, Kirwan GM. Hudsonian Godwit (Limosa haemastica). In: Del Hoyo J, Elliot A, Sargatal J, et al (editors). Handbook of the birds of the world alive. Lynx Edicions, Barcelona.