Monday, August 30, 2010

An emperor and a fritillary

Doxocopa pavon - Pavon Emperor (male)

Pavon Emperor and Gulf Fritillary, that is. These are not uncommon butterflies in Central America.

In Doxocopa emperors the proboscis (or 'tongue'), here only partially visible, is green.  Pavon Emperors, in the genus Doxocopa, are nymphalid butterflies, a family popularly known as brushfoots. Like all insects, the brushfoots have six legs, but the first pair of legs are greatly reduced in size - and in Doxocopa emperors, green.

Female Pavon Emperors have a wider white band on the undersides of the forewing and hindwing, and an upperwing pattern similar to Adelpha sisters. Only the males have a beautiful purple gloss on the upperwings, some of which is visible in the photo below.

Doxocopa pavon - Pavon Emperor (male)

Gulf Fritillaries are found from the southern United States south through Central and northern South America. They sometimes stray further north.

Agraulis vanillae - Gulf Fritillary

Brushfoots also, their front feet are quite reduced.

Agraulis vanillae - Gulf Fritillary

I photographed both individuals in Suchitoto, El Salvador, last Saturday.

Sunday, August 29, 2010

On thermoregulation in dragonflies

Brachymeria herbida - Tawny Pennant

As any mathematician will tell you, a group of objects with multiple attributes can be divided a number of ways. Dragonflies, for example, can be divided into species that spend a lot of time flying around ("fliers"), and species that sit around more and fly only short distances from their perches ("perchers").

Unidentified dragonfly

On hot sunny days, the dragonflies in the latter category, these so-called perchers, face the risk of over-heating. They reduce that risk by adjusting their posture, pointing their abdomen at the sun, thus minimizing exposure to the sun's rays. The top photos present two examples of perching dragonflies exhibiting this behavior.

Uracis imbuta (female)

Another strategy of course is to simply find a shady spot to perch.

I photographed these dragonflies yesterday in and around Suchitoto, El Salvador. If anyone can help me identify the second, smaller species, I'd love to hear from you!

Wednesday, August 25, 2010

Plain-capped Starthroats

Spurred on by a sighting of a Yellow-bellied Flycatcher outside SalvaNATURA's office yesterday - yet another sign that autumn bird migration has reached El Salvador - I birded the Botanical Garden briefly this morning. I found very little in the way of neotropical migrants, but I did stumble across a couple of Plain-capped Starthroats, which I had never seen in the city before. Later, I searched for city records in the SalvaNATURA database, but found only a 2008 record for the somewhat similar Long-billed Starthroat - at the exact same location. I found none for its Plain-capped cousin.

Plain-capped Starthroat is not that rare, although I suspect it is quite rare within the city limits of San Salvador.

Sunday, August 22, 2010


Most of the flowerpiercers in the genus Diglossa, which currently includes 14 species, are found in the highlands of South America. Two species occur in Central America, including the Cinnamon-bellied Flowerpiercer (Diglossa baritula) of which the male is pictured above.

As the common name suggests, these birds are nectarivorous. Because they feed on the same substrate, they're often found with hummingbirds, but instead of hovering in front of a flower and inserting a long bill, these birds have developed a different strategy. They perch at the base of the flower and with their uniquely shaped bill pierce a little hole in it, allowing them access to the flower's nectar that way.

Here's the duller female of the same species. (Clicking on the photo for a bigger view will reveal that this particular individual has a sizable tick feeding on the lower edge of her eye.) I photographed these birds last week in Monte Uyuca, Honduras, where I assisted Roselvy, Carlos and Vicky in SalvaNATURA's bird monitoring project. This is a monthly bird banding effort that started in January of this year, and which has been covered before in this blog. We banded about 75 birds there this time - but no flowerpiercers. A few months ago, we caught a ton of hummingbirds and quite a few flowerpiercers. This time around, only three hummers (two Green-breasted Mountain-gems and one Magnificent Hummingbird). Nearly all the hummingbirds and flowerpiercers, it seems, had moved 500-800 m downslope from the net lanes, for that is where I found these birds to be abundant this week. I even saw a male Cinnamon-bellied Flowerpiercer with one of our bands, about 600 m from the banding site.

It's possible that I banded this bird myself, although it is more likely to have been banded by either Roselvy or Carlos. Roselvy has been on all eight banding trips to the site, Carlos on seven I believe, while I have accompanied them on five. Altitudinal migration is well-known among tropical nectarivorous birds, as they opportunistically move from one area where flowers are blooming this month, to another area next month.

Once thought to be related to the sparrows and buntings of the New World, recent studies have shown flowerpiercers to be more closely related to the tanagers. The Cinnamon-bellied Flowerpiercer is found in Mexico, Guatemala, El Salvador and Honduras.

The other Central American flowerpiercer is Slaty Flowerpiercer (Diglossa plumbea), found in Costa Rica and western Panama. These birds are common in the Chiriquí highlands of western Panama, where Roselvy and I stayed for a week recently.

This is the male of the species; the female is duller brown, like the female Cinnamon-bellied.

Sunday, August 15, 2010

Lesser Nighthawks

Yesterday morning, Roselvy and I birded the mouth of the river Jiboa, near the Salvadoran airport of Comalapa. This spot nearly always has a good variety of birds, and in the past has produced regional rarities such as Glaucous-winged Gull and Baird's Sandpiper.

While we didn't find anything too extraordinary, we did encounter a nice mix of species, especially terns and shorebirds. Best bird probably was a Gull-billed Tern in a mixed flock of Royal and Black Terns, which also contained an Elegant Tern. A Black Skimmer was also present, and the first migrating Barn Swallows of the season were seen flying along the beach. In the shorebird department, species noted included Collared, Wilson's, Semi-palmated and Black-bellied Plovers; Willet; Greater Yellowlegs; Sanderling; Western Sandpiper; Ruddy Turnstone; Spotted Sandpiper; Whimbrel.

On the beach, near the little dunes directly adjacent to the river mouth, we found a flock of at least seven Lesser Nighthawks. These birds were cooperative and proved ideal subjects for trying out my new camera.

Friday, August 13, 2010

Magnificent Frigatebirds

A few more shots from the deceased Panasonic Lumix FZ-50. These were taken on the very last day of its life, on the southeastern coast of El Salvador, near the town of La Union.

All these birds are, of course, Magnificent Frigatebirds. The top bird is an adult male, while this white-breasted bird is an adult female.

Here's another male. I actually have my new camera already, a Canon PowerShot SX20 IS, but I haven't had opportunity yet to use it.

Magnificent Frigatebirds breeds in the Caribbean and on islands on both sides of Central and South America. Nobody knows where the nearest breeding colony for these birds in the Gulf of Fonseca is.

Tuesday, August 10, 2010

Panama: other cool birds

A few more shots from the Panama trip. The picture above is of a Common Potoo with chick, in Parque Nacional Metropolitano. This park is an excellent patch of primary tropical rain forest, within the city limits of Panama City. At just a ten minute, three dollar taxi ride from the hostel, we found this place worthy of a repeat visit. This particular bird, although not uncommon, is not frequently seen. A park ranger found it almost a month ago, and has been directing visiting birders to this spot.

Potoos are nocturnal birds found in the neotropics, and in shape and coloration resemble nightjars. They differ from nightjars in their larger size and upright stance. In the daytime, they roost by pretending to be an extension of a broken off branch of a tree. This bird, presumably because it has the chick, has altered its position somewhat, making it more conspicuous than it normally is while roosting.

In this same park we found a Streaked Flycatcher, I guess a common bird in Panama but for us a lifer. It looks a lot like the (for us) more familiar Sulphur-bellied Flycatcher, except its belly is whiter, and the chin is whitish, not dusky.

We found lots of cool birds in the park, but lighting conditions were such that most of the photos I shot came out as failures. To name a few: Keel-billed Toucan, Crimson-backed and Palm Tanagers, Black-bellied and Rufous-breasted Wrens (beautiful songs both) , Blue Dacnis, Yellow-crowned Euphonia, Yellow-headed Caracara, White-vented Plumeleteer, Dusky Antbird, and White-fronted Tyrannulet were some of the highlights.

Here's a view of the city, seen form the park. This skyline is quite unusual among Central American cities, and more reminiscent of a US or South American city.

Sunday, August 8, 2010

Panama: hummingbirds

Roselvy and I just returned to San Salvador from a 11-day trip to Panama, where we birded an excellent tropical rain forest near Panama City for a couple of mornings, and more extensively the area around Cerro Punta, in the western highlands of Chiriquí (pictured above).

Still 'between cameras' as it were, these are shots made with Roselvy's Nikon Coolpix L110. Despite the zoom, the megapixels and the image stabilization, this is not a camera for taking wildlife pictures, I found. Occasionally, a shot came out the way I wanted, but I'm definitely looking forward to my next camera, which I should have within the next couple of weeks.

The area around Cerro Punta is, at 2,000 m, quite beautiful, and home to many hummingbird species. At times I was able to get close enough for decent photos, and this entry will be about hummingbirds entirely. I'll save the non hummer photos for the next blog entry.

We stayed four nights at the excellent Los Quetzales Ecolodge in Guadelupe, a small village adjacent to Cerro Punta. The lodge had lots of hummingbird feeders up, and up to 12 species were easily seen. The bird pictured above is an immature Green-crowned Brilliant.

This is a male White-throated Mountain-gem. Although this species was common around the ecolodge, this photo was actually taken in the garden of Finca Dracula, a nearby orchid farm. (The name Dracula, incidentally, in this case refers not to the Count but to an orchid genus, and means 'little dragon'. I mention this, should it ever come up in a crossword puzzle...) The White-throated Mountain-gem is only found in southern Costa Rica and extreme western Panama. In fact, the Costa Rican subspecies cinereicauda (a.k.a. Gray-tailed Mountain-gem) is sometimes considered its own species, and some authors consider the range of White-throated Mountain-gem to be in western Panama exclusively.

Another locally common hummingbird, but one with a much wider range, is Magnificent Hummingbird. Because of its large range, this hummer has been featured quite a bit in this blog (for example, here and here).

Here it is once more, showing off its brilliant colors. These photos were taken just outside the hotel room, on the porch.

Green Violet-ear is another very common, easily photographed species there. This species too has a wider range, on the Central American Volcanic Belt from central Mexico to Panama, and then again in the Andes from northern Venezuela to Bolivia.

Here is a Snowy-bellied Hummingbird, also photographed around the ecolodge. This bird is found from southwestern Costa Rica to eastern Panama, mostly in lowlands and foothills, although we found it at 2,000 m.

The diminutive Scintillant Hummingbird, easily recognized as a Selasphorus, is more of a highland specialist, found in Costa Rica and western Panama at elevations between 1,200 - 2,100 m. The closely related Volcano Hummingbird replaces it above 2,100 m (Ridgely & Gwynne, 1989). We occasionally saw Scintillant Hummingbirds around the feeders, but they were often chased away by the larger species, and more frequently fed on flowers.

Other hummingbirds we saw in the mountains of Chiriquí, western Panama, include Stripe-tailed, Rufous-tailed and Fiery-throated Hummingbird, and, on the Tres Cascadas trail just outside the lodge, the rare and spectacular Green-fronted Lancebill.

Cited literature:
Ridgely, Robert S. & Gwynne, John A. (1989) A Guide to the Birds of Panama, with Costa Rica, Nicaragua, and Honduras, Second Edition, Princeton.