Monday, September 14, 2015

Birds migrate, eBirders count!

And it is again the time of the year where some impressive flocks of migrant birds can be seen in the sky on their annual southbound passage to South America through the Panama isthmus.  This is certainly true for the daylight migrants, like the raptors.  Since yesterday, some impressive flocks of both Plumbeous and Mississippi Kites have crossed Panama City's skies... although few Panamanians are aware of that.  For me, it was kind of special because I recorded for the first time a flock of Swallow-tailed Kites from my balcony.
Swallow-tailed Kites
Swallow-tailed Kite
Yes, now my balcony list stands at 118 species!  Just second before I recorded a huge flock of Plumbeous Kites that were new for my list too.  These birds approached from the southwest, took the thermal current very close to my apartment (thus I was able to see the black tails with white bars and the rufous primaries) and leave it very high flying eastward.
Plumbeous Kite
However, today was truly spectacular... at first, a little flock of 50 Plumbeous Kites flew low enough to see the same field marks I witnessed yesterday; then, a second group follow them with some Black Vultures... however, this were congeneric Mississippi Kites.  Notice the pale heads and pale secondaries of these birds.
Mississippi Kites and Black Vultures
While seeing this second flock, I noticed some "tiny spots" in the background.  After focusing it properly, I realized the these "tiny spots" were thousands of kites very high in the sky... too high to ID properly to species.  They were Ictinia kites for sure.  Immediately, I started to estimate the number of individuals in this Mississippi/Plumbeous Kites flock.  First, I quickly counted 100 individuals, got a sense of the proportion of the flock they take up and then extrapolated by hundreds the rest of the flock.  My estimation was 6000 birds.  It sounds straight forward... but it needs some practice; however, after a while you will make it automatically.  A very interesting article about counting birds can be found in the eBird main (or just click HERE).  Of course, to use this method you need a fairly uniform flock of the same species/group.  For example, this photo shows approximately one third of the flock I saw today:
All those dots are Mississippi Kites, with at least three Black Vultures mixed in (you may need to enlarge the photo)
For purely educational purposes, I divided this photo into four equal parts and counted individuals in one of these parties (which represent 1/12 of the original flock).  Do not pay attention to the size and shape of the red circles ... I only drew them for not count the same individual two or three or ten times!
533 Mississippi/Plumbeous Kites (and a Black Vulture); thus, a flock of 6396 individuals (533 x 12)
I did the same with the next picture, which I took with a larger zoom, and representing approximately one tenth of the flock:
Many Mississippi/Plumbeous Kites
578 Mississippi/Plumbeous Kites; thus, a flock of 5780 birds (578 x 10)
Using both estimates, I calculated an average: 6,088 Mississippi/Plumbeous Kites in that single flock (6396 + 5780 / 2).  That's why I wrote down that number in my eBird checklist and not my first estimate of 6000 birds... although they are pretty similar!  So what are you waiting for... it is time to practice and to look up for migrant flocks of birds!

Tuesday, September 1, 2015

Bird of the Month: Wedge-rumped Storm-Petrel

The Wedge-rumped Storm-Petrel (Oceanodroma tethys) is a relatively small member of the Hidrobatidae family (the Northern Storm-Petrels) that breeds on the Galapagos islands (nominate tethys) and on islets off the central coast of Peru (ssp. kelsalli).  This is the commonest storm-petrel species in Panamanian waters, present year-round, but commoner from May to November.
Wedge-rumped Storm-Petrel (Panama Gulf)
It is sooty brown overall (sooty black when fresh), with darker flight feathers and tail and pale upperwing panel and conspicuous white uppertail coverts.  There are slight differences among the two different subspecies, with kelsalli being smaller, shorter winged, shorter tailed, with smaller white "rump", slighter bill and with relatively long tail projection and more forked tail than nominate tethys.
Wedge-rumped Storm-Petrel (Panama Gulf)
Like other storm-petrels species, it have a steep forehead due to the large olfactory bulbs that facilitates a keen sense of smell, which is very important to locate food and for social interaction at its colonies.  Also like many other storm-petrels species, it can be seen pattering its feet on the waves while fluttering over the water.  This behavior is why it is call "Paíño Danzarín" in spanish (meaning "Dancing Storm-Petrel").
Wedge-rumped Storm-Petrel (off western Azuero Peninsula)
They are usually seen as small and dark little birds flying swiftly over the water among the waves, but they can be attracted by chumming to a boat, where you can have nice and prolonged views of these feathered marvels.
Wedge-rumped Storm-Petrel (Panama Gulf)
About specific ID to subspecies, more studies are needed to separate both subspecies in the field.  Presumably, all the photos in this post pertain to the kelsalli subspecies.  Notice the short arm, long tail projection beyond the white uppertail coverts, the forked tails and the small size noticed at sea.  We can not be 100% about the IDs, since both subspecies have been recorded in Panama and all these noted differences depend on wear, shape, angle of sighting, light and so on; however, some references indicate that the form found closer to shore is kelsalli, while nominate tethys seems to be more pelagic in general (more than 100 km from shore).  For these, and many other reasons, is why we chose the Wedge-rumped Storm-Petrel as our Bird of the Month!
Wedge-rumped Storm-Petrel (off western Azuero Peninsula)
Literature consulted:
1. Ridgely R, Gwynne J. A Guide to the Birds of Panama. Princeton University Press 1989.
2. Angehr G, Dean R. The Birds of Panama. A Field Guide. Zona Tropical 2010.
3. Howell SNG. Petrels, Albatrosses and Storm-Petrels of North America.  Princeton University Press 2012.
4. Carboneras, C., Jutglar, F. & Kirwan, G.M. (2014). Wedge-rumped Storm-petrel (Hydrobates tethys). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2014). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from on 1 September 2015).

Tuesday, August 25, 2015

Whale watching trip to the Pearl Islands

Last weekend, I went with my family on a private tour to the Pearl Islands, the heavenly archipelago within an hour and a half from busy Panama City.  My friend Mario Ocaña organized the trip and was a terrific host, and my whole family is impressed by his professionalism and camaraderie.  Our objective was to watch whales... but it was an open itinerary, and we included some time to enjoy the beaches (as in plural!), to have lunch in Contadora island and to visit some seabirds colonies.
Ready for adventure!
In fact, the first attraction was close to the dock.  Few minutes after leaving the marina, we were admiring hundreds of Blue-footed Boobies and other seabirds resting at the Peñón de San José, a rocky islet to the south of Flamenco Island.  However, the main attraction there were the three Peruvian Boobies resting on the rocks among the Blue-footed Boobies.  They are irregular visitors to Panama (only under abnormal conditions, like El Niño).
Peruvian and Blue-footed Boobies
Blue-footed Boobies
Brown Booby
As you can see, I'm including also a photo of a Brown Booby seen later and another pic of the Blue-footed Booby, both from Pachequilla island, the first of the Pearl Islands that we visited that day.  The sight of several hundreds of seabirds on the rocks made us feel like in a Nat Geo documentary!  A little bit after leaving Pachequilla, we encountered our first pair of whales: mother and calf Humpback Whales!
Mother and calf Humpback Whales
These warm and shallow waters are perfect for the whales to raise their young.  Soon these beasts will engage on an epic transequatorial journey to their feeding grounds around Antarctica.  The second whale appeared shortly after the above pair close to Contadora island... as Mario says, the harder whale to find is the first one!
Humpback Whale (Contadora island in the background)
With the whales in the bag, we decided to enjoy the white-sanded beaches of both Mogo Mogo and Chapera islands... the Survivor: Pearl Islands sets.  We had the whole beaches for us, and the little ones enjoyed it most (specially Gabrielle, after her slight disappointment after realizing that whales were not purple, as her toy whale).
In our way to Contadora island, we saw some Wedge-rumped Storm-Petrels.  For most of the participants, they were little dark bat-like birds flying swiftly and in zig-zag among the waves... this photo shows that they are delicately patterned in brown and buffy, with contrasting white uppertail coverts.
Wedge-rumped Storm-Petrel
And of course we saw more Humpback Whales!  Several more, including pairs of mother and calf, solitary adults and even a distant group of adults flapping their flippers and jumping out the water!  The show was amazing and soon we were joined by several other boats admiring the whales as well.
Noisy blow
The ride back to Panama City was a bumpy one, but we were more than happy after enjoying these nature marvels so close to the big, busy city.  While we were having a sunny day at the islands, a huge storm system was whipping Panama City... but we made it without experiencing any rainstorm at all!  I want to thanks Mario for the excellent trip, and hope to repeat it soon my friend!

Sunday, August 16, 2015

Pelagic off Western Azuero

The pelagic avifauna of Panama is essentially unknown.  Very few, if any, pelagic birding trips are done off Panamanian coasts, specially off the Azuero Peninsula (central Panama) where the Continental Shelf break is close to shore.  Several new species for Panama have been recorded in those trips in the last five years, including Tahiti Petrel, Pink-footed Shearwater and Band-rumped Storm-Petrel, while many others have been confirmed and documented adequately.  That's why a pelagic trip in Panama is always exciting.  So, more or less one month ago, we took the opportunity to make a pelagic trip off the Azuero Peninsula again... but this time from its western side... departing from Reina beach close to the town of Mariato.  Our friend Kees Groenendijk (who runs the charming Heliconia B&B in the town of Malena with his wife Loes) organized everything: lodging, boat, captain (Tim), chum and snacks... so it was not difficult to convince George Angehr, Howard Laidlaw, Rafael Luck and Euclides -Kilo- Campos to join us in the adventure!
Rafael, Euclides, Howard, George, Jan and Kees
The Continental Shelf break was still one and a half our away to the south from the departing point, but the inshore waters were full of life, with American Oystercatchers and Collared Plovers at the sand of Reina beach, with over-summering Willets, Whimbrels and a lonely Spotted Sandpiper.  Soon, we started to see the first Brown and Blue-footed Boobies for the day, plus many Magnificent Frigatebirds, Brown Pelicans and even a pod of Bottlenose Dolphins close to Cebaco island.  Kees showed us some rocky islets close to Punta Naranjo (Azuero's southwestern corner) that were covered in Brown Noodies.  This tern is seldom seen so close to shore in Panama.
Rocky islets close to Punta Naranjo (and a Brown Pelican)
Brown Noodies 
The omnipresent Magnificent Frigatebird dwarfed the Brown Noddies, although they are quite large for a tern.
Magnificent Frigatebird and Brown Noody
At this point we started to see real pelagic birds. The Continental Shelf break drops steeply VERY close to shore in this part of the Azuero Peninsula... in fact, most of the pelagic birding was done having the southern Azuero coast within sight.  Kees started to chum at several spots along the break... soon, we were surrounded by several Black and Wedge-rumped Storm-Petrels attending the slick. I have to admit that this was the first time I saw those species so close and in detail!
Wedge-rumped and Black Storm-Petrels
Black Storm-Petrels
Black Storm-Petrel
Wedge-rumped Storm-Petrel
These small tubenoses are well adapted for the rough seas, in spite of their size.  Most (if not all) of the Black Storm-Petrels seen were in wing molt, probably indicating non-breeding birds on its second cycle (year) at this date.  About the Wedge-rumped Storm-Petrels... I don't know if they can be ID to subspecies in the field.  Both the nominate tethys and kelsalli forms have been recorded in Panamanian waters.  These birds were evidently larger than the Least Storm-Petrels seen nearby and the wings looked narrow and long, with a shallow tail fork (they looked square-tailed in the field and in the photos), all consistent with nominate tethys.  As I mentioned earlier, we also saw some Least Storm-Petrels.  They showed little interest in the chum and only visited the slick for few seconds; however, I managed a diagnostic photo showing the graduated tail and the dark plumage resembling Black Storm-Petrel.
Least Storm-Petrel
The storm-petrels were the highlights of this trip due to the prolonged and detailed views of the birds, but we also recorded several Galapagos Shearwaters (all of them of the "light-winged" variation), a definitive Pink-footed Shearwater (fifth report for Panama, second one documented with photos) and a Nazca Booby flying to the west above the Continental Shelf break.
Galapagos Shearwater
Pink-footed Shearwater
Nazca Booby
The pelagic birds were not the only highlights of this trip.  At some point, we saw no less than four Humpback Whales, with one young animal leaping off the surface almost completely!  This, plus the dozens Pantropical Spotted Dolphins off shore in a feeding frenzy, the Bottlenose Dolphins inshore and the Spinner Dolphins spotted by some of the group (not by me), made it a four-species-day of cetaceans!
Humpback Whale
Pantropical Spotted Dolphin
I wish to thank Kees and Loes for receiving us and for organizing this amazing trip.  I know I'll be back to western Azuero soon... and not only for the pelagic birding because the area is home to many endemic taxa and other nature marvels.  See you soon!

Wednesday, June 3, 2015

Hungry birds

The exposed mudflats, mangroves and beaches of the Upper Bay of Panama are a very important feeding station for both migrant and resident waterbirds and waders year-round.  The simply amazing numbers of peeps and other shorebirds that spent most of their lives here are prove of that.  But this time, I want to highlight that almost during every visit I witness a waterbird catching/eating large catfishes... like this Great Egret in Costa del Este.
Great Egret
The habitat is just ideal for the catfishes, so I guess they abound and are quite easy to catch. Sometimes, the birds just take them from the mud... or, in the case of the Magnificent Frigatebirds, are stolen from other birds.  This is a repetitive scene in Panama Viejo (where I took the next photos): a lucky bird catch a fish just to be harassed by these feathered pirates... and who can resist those bandits?
Magnificent Frigatebird
The Magnificent Frigatebird is a specialized kleptoparasite... parasiting by theft.  However, as it usually happens, this frigatebird was not the only one patrolling the site and soon another individual tried to steal the prize.
Two Magnificent Frigatebirds after the fish
Seeing those two frigatebirds in the air is fun.  The large birds are extremely agile in the air, and elegant... even when they chase each other.
Agility in the air
Eventually, the catfich fell to the floor... after all, nobody knows to whom is working... the birds spend 10 minutes disputing the catfish just to give it to a cat that was just passing by.
What can I say?  Some are luckier than others!

Monday, June 1, 2015

Bird of the Month: White-rumped Sandpiper

The White-rumped Sandpiper (Calidris fuscicollis) is a small to medium-sized shorebird, one of the largest peep species, that occurs rarely in Panama during its fantastic migrations.  Think about it... a bird that barely reach a length of 7 inches, a weight of 2 ounces and that breeds in Artic Canada and Alaska flies 15,000 km every year TWICE to and from its wintering grounds in Tierra del Fuego.
White-rumped Sandpiper
After leaving their breeding grounds, these birds fly out above the Atlantic Ocean to northern South America, where they start a trans-Amazonian journey to their wintering grounds.  During the northbound passage, they reach central North America via the Caribbean.  That's why they are so rare in Panama, which is not on their usual migration route.
White-rumped Sandpiper
The slender profile is due to the elongated wings, an adaptation to their long-distance migrations.  The slightly larger size and longer legs compared to other peeps sandpipers make them easily spottable  when mixed with other species while feeding or resting.
Short-billed Dowitcher, Semipalmated and White-rumped Sandpipers
Among the peeps, it is the only one with white upper tail coverts (the "rump"... in fact, it is dark-rumped), a field mark mostly visible when the birds flies, but sometimes while feeding or preening.  Is particularly useful if you inspect a tight flock of peeps in flight.
White-rumped Sandpiper flying
For these, and many other reasons is why we chose the White-rumped Sandpiper as our Bird of the Month!As I mentioned earlier, it is a rare transient migrant throughout Panama, always in small numbers.  It has been recorded in both coasts along the Canal Area and western Bocas del Toro.  During this last spring passage, it was recorded in the Pacific side of the Panama Canal (where I took all these photos) and Bocas del Toro... a remarkable set of reports for this species in Panama (we saw at least 15 different individuals in one site).
At least five White-rumped Sandpipers in this shot
For these, and many other reasons is why we chose the White-rumped Sandpiper as our Bird of the Month!
White-rumped Sandpipers
Literature consulted:
1.  Ridgely R, Gwynne J. A Guide to the Birds of Panama. Princeton University Pres 1989.
2.  Angehr G, Dean R.  The Birds of Panama. A Field Guide. Zona Tropical 2010
3.  The Cornell Lab of Ornithology All About Birds.  At