Saturday, December 26, 2009

Last flock around La Esperanza

Today more Golden-cheeked Warbler shots, because today I was able to get many close-ups of these fantastic warblers. This morning we did our fifth and final flock here in La Esperanza, and if you've just tuned in and don't know what "doing a flock" really means: we're describing mixed warbler flocks in the pine-oak forests of Honduras, as part of a study of the winter ecology of the Golden-cheeked Warbler.

Again two individuals in today's flock, and again both of them adult males! This bias toward adult males so far is really quite remarkable. In this species, there is some segregation between males and females. The males tend to winter further north, in Chiapas (Mexico) and Guatemala, closer to the breeding grounds in Texas.

Here in Honduras, we're in the core winter range for this species, and in previous years females and immatures outnumbered males in this part of the winter range.

Last year's team found three adult males and eight adult females at this field site. This year we found five adult males, one immature male and one immature female. Keep in mind that adult females and immature males are very hard to separate in the field. For a discussion on how we separated those earlier two immature birds, see previous posts.

We saw both birds simultaneously, and thus were able to determine there were (at least) two adult males in today's flock. The flock was fairly small, and was comprised of 26 individuals, representing 16 species.

One of today's flock members was this 'female-type' (could be an immature male) Black-throated Green Warbler. This species is closely related to the Golden-cheeked Warbler, but shows an auricular patch on the face and yellow in the vent, which goldencheek never does. The upperparts are lighter on a BT Green - green, not olive - but in this underlit photo appear deceptively dark.

One site down, four more to go. Next stop national park Cusuco, on the Atlantic slope. We'll be staying in Buenos Aires, a small village in the beautiful mountains there. There is no electricity in Buenos Aires - never mind internet - so it will be a while until the next update.

Friday, December 25, 2009

Red-faced Warbler

This is another adult male Golden-cheeked Warbler, one we had in the flock today on the same trail where we collected data yesterday. This flock was almost two kilometers from yesterday's flock, and can safely be assumed to represent different individuals.

With yesterday's two adult males, this brings the total here in La Esperanza now to three adult males of a total of five individuals. That's a high percentage of adult males for this part of the wintering range, and one that most likely is not going to hold as the season progresses.

Of course we were happy finding this bird, but the real surprise today was a Red-faced Warbler, which here in Honduras reaches the southern limit of its range, and is not common. Last year I worked on the same project in Chiapas (Mexico), where this species is more common. I have seen Red-faced Warbler before in Honduras, as a matter of fact close to the Nicaraguan border, near San Marcos de Colón. As far as I'm aware, this bird has never been recorded in Nicaragua. The photos I was able to get show a barely identifiable blur, so I'll spare you those.

Another cool bird today was White-breasted Hawk. According to the wikipedia page, still a subspecies of Sharp-shinned Hawk, but a candidate for a split. Its plumage certainly is quite different. Not exactly a rare bird in Central American pine-oak forests, but I had never seen one perched, only in flight. This bird perched in the flock area, and when we discovered it, we knew why all the passerines suddenly had become quiet.

With only one remaining flock to describe here in the area of La Esperanza, we're almost done. So far, every flock here had at least one goldencheek. We're in the core winter range and in suitable habitat, so finding a goldencheek here isn't too hard. Our next field site, Cusuco on the Atlantic slope near San Pedro Sula, is a bit of an outlier, and finding goldencheeks there is more difficult.

Internet access there too is more difficult - non-existent the last time I was there - so it may be a while until the next update.

Happy New Year!

Thursday, December 24, 2009

More goldencheeks

This is the second Golden-cheeked Warbler we found here in la Esperanza. It's the bird we saw the day before and that I posted a photo of in the previous entry, an immature female. We went back there the next day - yesterday - to describe a flock, in hopes of encountering this individual as one of the flock members. And sure enough, the same bird was still there.

The above photo shows a whitish throat and yellowish upper chin, with very little black streaking on the breast. Also visible on this bird (but not in this photo) were heavily abraded rectrices, another indication of an immature bird. It's hard to say whether this is an immature female or immature male, but based on how lightly marked this individual appears, I'm inclined to think it's an immature female.

This bird has an all-black throat and chin, and is an adult male. We found it today, on our third field day here in La Esperanza, as a member of today's large flock, which also included a second adult male goldencheek, and an adult male Golden-winged Warbler. That, incidentally, was our third Golden-winged Warbler here: so far, every flock has had one. Remarkable, since last year's crew had one Golden-winged Warbler here, which they considered a noteworthy sighting in their report. I tried to get photos of today's individual but did not succeed.

Note that this Golden-cheeked Warbler is photographed in a pine. This particular individual spent a lot of time foraging in pines. This is somewhat unusual, because the species has a preference for thin-leaved ('encino') oaks, and these were abundantly available in today's flock area. We saw it foraging in oaks in the middle layer also, but at times it would forage higher in the pines with the Hermit Warblers, which habitually do this.

Here's a photo of a goldencheek in encino oak, playing peekaboo. I took this photo shortly after we encountered the second adult male goldencheek, but I believe it is still the same first individual also pictured above.

Same bird. Note the blackish upperparts, very different from the olive upperparts on that immature female.

Finally, a couple of butterfly photos from today, both 'sisters' of the Adelpha genus. This is a Montane Sister. It shows the classic 'sister' pattern: a white band along the upper median hindwing continuing to the upper forewing, and a series of orange spots on the distal part of the upper forewing. Practically all Adelpha sisters show this pattern, and species are distinguished based on slight variations.

This Orange-striped Sister deviates from that basic pattern by replacing the white band with an orange band. In the region, only the Veracruz Sister shows this pattern, but the edges of the orange band on the upperwing are more concave, not practically straight as here, while the orange band on the hindwing on that species narrows considerably towards the end, much more so than on this butterfly.

I dedicate these photos of sisters to my own sister, who is currently visiting in Holland, over from New Zealand where she lives. I wish I could have spent Christmas with her and the rest of the family in snowy Holland, but here I am in a mountainous village in Central Honduras, looking for warblers. I love doing this, but I also miss the folks back home.

To my family, friends and all readers of this blog: a very merry Christmas!

Tuesday, December 22, 2009

The first goldencheek

Yesterday we got rained out, but today we were able to go out into the field in search of our first mixed warbler flock at our first field site this season, La Esperanza. We found a flock that consisted of 34 individuals representing 19 species, including one Golden-cheeked Warbler.

Lighting conditions were far from ideal, so I don't have any calendar photos. I took many photos and the ones shown here are the 'best', i.e. least shitty.

That this is a goldencheek should be fairly obvious. But what sex and age is this bird?

This is where it gets complicated. "The extreme upper chin is yellow in all females," according to Dunn & Garrett (1997). Our bird appears to show a dark upper chin, with a yellow patch on the throat. The forehead, crown and hind neck all appear nearly black. In the field, from most angles, those parts appeared black. In the upper photo, with the bird seen from the back, those parts appear blackish with dark olive centers to the feathers. The back appears dark olive with broad black streaks.

The head-on shot shows an obvious yellow median stripe on the forehead, which according to Dunn & Garrett (1997) is more pronounced in adult males than in other plumages.

So we have a dark upper chin, a dark forehead, crown and hind neck, and a pronounced median stripe on the forehead all arguing in favor of a male. I think this bird may be an immature male - mainly based on the dark upper chin - since it is clearly not an adult male: the upperparts would have to be black; and apparently not a female: the chin is dark.

Here's a different bird, one we saw after we described today's flock and drove a little further to scout for tomorrow's location. Again not a work of photographic genius, but still recognizable as a goldencheek. Click on the photo for a bigger view, and you will note that this bird has a light upper chin. The crown seems lighter too, compared to the bird discussed above. My best guess would be an immature female for this bird. We'll go back to this site tomorrow to describe the flock there. Hopefully this bird will be in it, and hopefully we'll get better looks and who knows, maybe even better photos.

Other flock members in today's mixed warbler flock included a Golden-winged Warbler, a pair of Hepatic Tanagers, three Hermit Warblers, two Grace's Warblers, a Greater Pewee, a Blue-headed Vireo, a Buff-breasted Flycatcher, two Slate-throated Redstarts, three Townsend's Warblers, three Tennessee Warblers (there were more in nearby flowering trees), two Acorn Woodpeckers, two Black-and-white Warblers, a Painted Redstart, three Wilson's Warblers, two Black-throated Green Warblers, a Northern Flicker, a Golden-Olive Woodpecker, and two Brown Creepers.

Literature cited:
Dunn, Jon & Garrett, Kimball (1997) A Field Guide to the Warblers of North America; Peterson Field Guide Series 49; Houghton Mifflin, New York.

Monday, December 21, 2009

Looking for Gampsonyx

We're in Honduras! After nearly a month of waiting in El Salvador, Kashmir and I were finally able to take off Saturday and embark on another field season looking for Golden-cheeked Warblers in Honduras.

Piggybacking on this project we planned brief visits to a couple of sites in western El Salvador and southern Honduras, where earlier this year first observations of Pearl Kite (Gampsonyx swainsoni) for each country were made. An article describing these first records is currently in press. We figured we might as well revisit these sites, as they were more or less on the way to Tegucigalpa, where we would meet up with our Golden-cheeked Warbler field assistant Fabiola.

Saturday morning we left San Salvador and drove out to the department of La Unión in western El Salvador, to go to Playa El Icacal, near the town of Intipucá.

It took a bit of searching and a flat tire to reach our destination. The searching brought us to areas that appeared to qualify as potential Pearl Kite habitat, so I didn't consider this a waste of time. We scanned every treetop and all wires for this small raptor, but did not encounter it.

This is where Oliver, Roselvy and I saw an immature Pearl Kite back in March of this year. Kashmir and I scanned the area carefully, but did not find it. Unfortunately, we didn't really have that much time because we still had to cross into Honduras and drive to our next destination, Choluteca, the same day.

Choluteca is a town in southern Honduras where Honduran biologist Mario Espinal, one of my coauthors on the Pearl Kite article, saw and photographed the first record of this species for Honduras in April of this year. Since then, he has observed the species a couple more times in this area, which suggests that there may be a small pioneering population in the region. Our goal was to collect more evidence to substantiate that hypothesis.

Early Sunday morning we set out for a dirt road south of the town of Choluteca, where a couple of sightings were made. This time we found the dirt road very easily. This, it would seem, is what Pearl Kite habitat looks like: cattle pastures with scattered acacias.

The two raptors we did encounter here were Crested Caracara and American Kestrel. Both species were common. But two and half hours of fairly intensive scanning did not yield any Pearl Kites. If the species is indeed a resident here, not merely a vagrant, it seems to be an uncommon one.

Common birds here included Groove-billed Ani, Ruddy Ground-Dove, Great Kiskadee, and Tropical Kingbird. These are of course all species common in disturbed habitats throughout Central America.

Particularly abundant was Scissor-tailed Flycatcher, a winter resident here.

Another common winter resident here was Mourning Dove.

Around nine we returned to Choluteca for some breakfast, and then drove on to Tegucigalpa, to meet up with Fabiola and to do grocery shopping. Mid-afternoon, we left Tegucigalpa and drove to our first field site, La Esperanza. At 2000 m, this is our highest - and coldest - field site. Night fell as we reached Siguatepeque, where we turned onto what by daytime is a very scenic route, winding through the mountains to La Esperanza.

In the morning, the weather had been sunny and agreeable in Choluteca. Here in central Honduras, it was overcast and rainy. As soon as we turned onto that winding mountain road, we hit dense fog - clouds - and the driving on this dark, unlit road became extremely difficult and hazardous. We made it to La Esperanza a little later than initially planned, because I had to drive slow in many places.

Then finally today, Monday, we were supposed to go out and describe our first mixed warbler flock here in the forests surrounding La Esperanza, but hard rain prevented us from going out into the field. It was raining all night and is still raining as I write this. We'll go out and hit several of the field sites today, just to reconnoiter and refresh my memory of sites we did when I was here last, two years ago. We'll also try to get our spare tire fixed.

It seems to me that we've been struck by an uncommon amount of bad luck recently, and I'm starting to think the cosmos owes me big time, if it cares in any way about restoring karmic balance...

Friday, December 18, 2009

About to go

When Kashmir and I traveled down to El Salvador almost a month ago, we anticipated spending little time in El Salvador before heading out to Honduras and Costa Rica, in search of Golden-cheeked Warblers. This study, now in its fourth year, is carried out in five Central American countries: Mexico (Chiapas), Guatemala, El Salvador, Honduras and Nicaragua. A sixth country - Costa Rica - lies outside the species' known wintering range, although recent records suggest that it may winter there in small numbers. We were going to investigate that.

But we're still in El Salvador, and though we've seen many cool birds, we have yet to see our first Golden-cheeked Warbler this winter.

The main reason for our delay has been lack of funds. The study is funded, but on a reimbursement principle. To put several crews into the field requires a sizable working capital, which our client in today's global financial crisis does not have. At one point, there was even talk of postponing all field work on this project to next winter.

However, we are now almost ready to go to Honduras and do a 5 or 6 week field season there. We're hoping to resolve several smaller bottlenecks today so we can leave for Honduras either today or tomorrow. Field work in Costa Rica has been postponed to next winter.

Meanwhile, we've been guests on SalvaNATURA's bird monitoring project, and assisted with vegetation sampling on a Scarlet Macaw reintroduction program. Here are some snapshots from these activities.

Here's Karla, project coordinator on SalvaNATURA's Scarlet Macaw reintroduction program, interviewing an elder about various animals, including Scarlet Macaw, that he may have seen in his youth. He remembered seeing Scarlet Macaws in the 1940's in southwestern El Salvador, where Karla is conducting the interviews. In the foreground a video camera, which I operated that morning. Other work Kashmir and I helped out with on this ambitious project was collecting vegetation data on potential food supply trees in El Imposible.

We also spent a bunch of time banding birds, in a small forest near a coffee plantation in the Santa Ana area, and also at a higher elevation in Los Andes, a part of Parque Nacional Los Volcanes.

Here's a close-up of a Rufous-and-white Wren.

I banded this Slate-throated Redstart. This species, incidentally, is also found in pine-oak forest and is a regular flock member of mixed flocks that also include Golden-cheeked Warblers.

In Los Andes, a good portion of the birds we caught were hummingbirds. This is a male Green-throated Mountain-gem.

This magnificent hummingbird is a Magnificent Hummingbird.

The last bird I removed from a net yesterday was this Rufous Sabrewing, a lifer for me.

I wish to express heartfelt thanks to various SalvaNATURA staff (especially Lety, Carlos, Roselvy, Vicky, Ricardo, Karla and Robin) for providing us with the opportunity to assist them on their projects. We learned a lot from all of them, and the time spent waiting for our own project to start was not wasted.

Tuesday, December 8, 2009

A leaf litter frog

Today a photo of a leaf litter frog from national park El Imposible in El Salvador. I forget the name of the species, but this time let's not talk about the frog - let's talk about the photo. First I should perhaps mention I don't consider myself an accomplished photographer by any means. I may illustrate this by admitting that I use a point-and-shoot camera, and that I rarely use manual camera settings. I'm very much an amateur. This frog photo for example has many technical imperfections, the most obvious perhaps the blur in the top middle of the frame.

Also, the frog is poorly lit and barely visible.

Yet I like this photo a lot, and I think its technical imperfections accidentally translated into compositional strengths. I shot several frames of this tiny frog (2 cm in length), and all the others show an over-exposed frog in direct sunlight, with very little depth in the photo. Here at least we do experience depth, and the blurring in the top center of the leaf for me only exemplifies the transient quality of sunlight on the forest floor, in the obscure, shimmery world this little frog inhabits.

Sunday, December 6, 2009

El Imposible

About two weeks ago, field assistant Kashmir and myself traveled down from Mexico to El Salvador, to start on the fourth field season studying the winter ecology of Golden-cheeked Warblers in Central America. But matters beyond our control have thus far prevented us from starting with the project, so we have been birding in El Salvador instead. We spent most of our time in a national park called El Imposible, where I stayed before (see here and here).

Long-tailed Manakins (an immature pictured above) are common here, and their melodious call is often heard. This bird is called Toledo in Spanish, a fairly accurate representation of that call.

One of the most common neotropical migrants here is Tennessee Warbler, a fairly drab looking warbler that is superficially similar (but unrelated) to Old World warblers in the genus Phylloscopus, like the Chiffchaff or the Willow Warbler.

Herpetofauna is well represented in the park, and includes this small but charismatic amphibian, the Maki Frog. They are hard to find in the daytime, but come out at night to sit on leaves overhanging wet spots in the park.

The last few days we were there, Kashmir and I assisted with the bird monitoring project in El Imposible. In this photo, Kashmir is taking notes while Ricardo is processing a female Elegant Trogon.

Familiar neotropical migrants such as this Black-and-White Warbler are abundant in the park. In this part of the winter range, females are more common than males.

Another very common winter visitor to the park: Swainson's Thrush.

A tropical family with three representatives common in the park is that of the woodcreepers. This is an Ivory-billed Woodcreeper. Ruddy and Streak-headed Woodcreepers are also found here.

An exciting late-afternoon catch was this Northern Bentbill, a 'lifer' (first sighting) for me. I removed this bird from one of the nets in the very last net run Friday. Although daylight was fading, it wasn't quite as dark as it seems in this picture. Shortly after its release, we heard its odd referee-like whistle.

We saw many other exciting birds here, including King Vulture and Black Hawk-Eagle almost daily. I had hoped to see White Hawk here also, but that bird was more elusive. It is more commonly seen in an area of the park that we didn't get a chance to visit this time. I did find another, rather unexpected lifer during a short visit to nearby Barra de Santiago, a strip of mangrove forest and beach on the Pacific coast. There we found a Black-vented Shearwater in a mixed flock of terns and pelicans fishing on a school of fish, close to the beach. This is a small shearwater that is found in Baja California. Unlike most shearwaters, it tends not to wander too far from its breeding grounds. It is still a rare bird in El Salvador, although it may be more regular here than previously thought, for this represents the seventh or eighth sighting within the last couple of years, according to Oliver Komar.

Now back in San Salvador, we should be on our way to Honduras and Costa Rica in a matter of days.