Hummingbirds in Monte Uyuca

Azure-crowned Hummingbird

After two months of hawk counting on Sandy Hook, NJ, I'm back in Central America, really now my home away from home. I was very happy, obviously, to be reunited with my girlfriend Roselvy, and also to see my good friend Oliver again. They picked me up from the airport in Tegucigalpa Wednesday around noon, and a couple of hours later Roselvy and I were already putting up mist nets in Reserva Biológica Monte Uyuca, not far from Tegucigalpa. This is a biological reserve where we have banded together many times before since Roselvy set up the banding station here in January 2010. Since then, we've carried out monthly banding pulses consisting of 400 net hours each month, most of which I have worked on as a volunteer bird bander.

The station is located in pine-oak forest with a well-developed shrub layer, and is home to many hummingbirds. Five species are found here more or less year-round, although their numbers fluctuate seasonally, in some cases dramatically so.

In May of 2010, we caught more birds (the majority hummingbirds) than in any other month of that year, and we were of curious to see if this surge would repeat itself in 2011. The previous record number of captures during one banding pulse there stood at 202 birds, caught in May 2010.

This May, we caught 217 birds - no fewer than 156 of them hummingbirds!

Besides the expected species, we caught three new hummingbird species for the station!

Many Central American hummingbirds are considered non-migratory, resident species. However, a lot of these resident species opportunistically undertake small-scale movements in search of flowers, which may be locally available at different altitudes during the year. Local altitudinal migration may account for the seasonal patterns we've found for various hummingbirds at Uyuca (Juárez & Komar, 2011).

Azure-crowned Hummingbird

In Uyuca, no species exhibits this seasonal variation more than Azure-crowned Hummingbird. We typically catch a handful of this species throughout the year, but their numbers increase in April and then explode in May. This week, we had 93 captures of this species, with only a few recaptures. We suspect that during the rest of the year, these birds are found a few hundred meters downslope, when the shrubs there are in flower. An afternoon walk in that area, just outside the reserve, seemed to support our conjecture, for we found few hummingbirds and few flowers where both can be very common at other times of the year.

hummingbird's eye view of Palicourea padifolia

Right now, a shrub with yellow flowers (Palicourea padifolia) is blooming abundantly in the area where the net lanes are situated. This plant depends on hummingbirds for its pollination, and provides food for many hummingbirds. It is found in middle-elevation cloud forests from southern Mexico to Panama (Taylor 1989).

Azure-crowned Hummingbird probably breeds in modest numbers right where the banding station is located, but moves into that area - possibly from downslope - in larger numbers a few months after the breeding season. Many adults we caught were either molting or had just finished their prebasic molt. This molt usually takes place after breeding.

White-eared Hummingbird

Another species that shows the same pattern, albeit less pronounced, is White-eared Hummingbird, also a pine-oak specialist. This pulse we caught 37, against only a few during each month the rest of the year.

immature female Green-breasted Mountain-gem

The Green-breasted Mountain-gem shows a different pattern. This species is a common breeder at the bird monitoring station, and we typically catch most of them right after the breeding season, in January and February, when their numbers are augmented with recently fledged individuals. They are present in good numbers most of the year, with a dip in July and August (Juárez & Komar 2011). Possibly this species does something similar to what the Azure-crowned and White-eared Hummingbirds do: it may visit their principal breeding area further downslope in the middle of the rainy season, when flowers in that drier part of the mountain are abundant. Obviously, this is all still speculation at this point, and could be an excellent topic for further study.

The other two species that we catch most banding pulses but do not seem to show any distinct seasonal variation are Magnificent Hummingbird and Green Violetear. While we did catch a violetear, we didn't have the mag this time.

That said, no fewer than three new hummingbird species for the station were found this banding pulse! After more than 6,000 net hours since January 2010, I'd say that is quite remarkable.

adult male Slender Sheartail

One of them was this stunning Slender Sheartail, a species found in southeastern Mexico (Chiapas), Guatemala, El Salvador and Honduras. In Uyuca, we are at the southeastern edge of its range.

adult male Slender Sheartail

Holding this bird in the hand was a first for me.

adult male Blue-tailed Hummingbird

Another was this equally gorgeous Blue-tailed Hummingbird, found in southern Chiapas and in the three countries around the Gulf of Fonseca: eastern El Salvador, southern Honduras and western Nicaragua. This species is usually found at lower elevations, and was certainly a surprise at Monte Uyuca, located between 1600 and 1700 masl.

adult male Blue-tailed Hummingbird

This bird also was in fresh plumage.

Cinnamon Hummingbird

Also more a lowland species - very common even in disturbed habitats like major cities - is Cinnamon Hummingbird. We had never caught this species before in Uyuca, but this pulse caught no fewer than three individuals. The above individual is molting its primaries.

Thanks to José Linares for help with the identification of Palicourea padifolia.

Cited literature:
Juárez, R. & Komar, O. 2011. Monitoreo Permanente de Aves en Reserva Biológica Monte Uyuca, Honduras, durante 2010, primer informe anual. SalvaNATURA, Zamorano, ICF.
Taylor CM. 1989. Revision of Palicourea (Rubiaceae) in Mexico and Central America. Systematic Botanical Monographs 26: 1–102.

Fledgling White-eared Hummingbird

Yesterday I photographed this fledgling White-eared Hummingbird in Reserva Biológica Monte Uyuca, Honduras. For many hummingbird species in northern Central America, the breeding season is nearly over. Note the extensive rufous edging on the head and back, indicating a young bird.

Immature hummingbirds

Green Violetear

In Reserva Biológica Monte Uyuca (Honduras), where Roselvy, Vicky and I banded last week, five species of hummingbirds are common: Green-breasted Mountain-gem, Green Violetear, White-eared Hummingbird, Magnificent Hummingbird, and Azure-crowned Hummingbird. They've all recently bred or are still breeding, for we caught immatures of each species, as well as an adult female Green-breasted Mountain-gem with an egg in her oviduct.

Let's take a look at these immature plumages. Few field guides illustrate them, although the Howell & Webb guide to the region does routinely describe them, if not in very much detail. Generally, younger birds are characterized by buffy feather tips on the upper and sometimes under parts. In the hand, presence of bill striations (fine corrugations along the side of the maxilla) indicates a younger individual. (Double clicking on these photos will reveal them in some cases.)

The top bird is a young Green Violetear. It will lose those buffy tips on the head and back through a first prebasic molt during its first life year. Those dusky underparts will become metallic green.

Azure-crowned Hummingbird

 Here's a young Azure-crowned Hummingbird. This bird too has extensive buffy fringes on the head and upper parts. In this species, the buffy tips of younger birds even extend to the tertials.

Magnificent Hummingbird

Immature Magnificent Hummingbird, with buffy (upper side) or whitish (under side) feather tips all over, again including the tertials.

White-eared Hummingbird

A tiny White-eared Hummingbird, weighed only 3 grams (the adults are tiny also, of course). Here we see buffy tips to the head and lower back feathers.

White-eared Hummingbird

Here's another look at the same bird, showing those buffy tips to the lower back feathers. Adults have all-green backs.

Both sexes of Green-breasted Mountain-gem show dusky greenish throat feathers, which they quickly replace with (usually buff-tinged) whitish feathers in the case of the female, or bright green feathers with white borders in the case of the male.

Green-breasted Mountain-gem

Here's a female. Note the buffy tips on the head and back, and the dark throat feathers, both characters associated with immatures in this species.

Green-breasted Mountain-gem

And here's a male. This individual shows a distinct rufous spot over the eye, found in many but not all young individuals of both sexes in this species. A few basic (post-juvenal) throat feathers have already grown in.

Green-breasted Mountain-gem

Young Green-breasted Mountain-gems too show rufous tips to the feathers of the lower back. In this species, males of all ages show dark upper tail coverts, a character lacking in females.

The variable song of the White-eared Hummingbird

female White-eared Hummingbird, January 2011, Montecristo, El Salvador

White-eared Hummingbird is one of the most common hummingbirds of Mexican and northern Central American pine-oak forests, a bird highly characteristic of its habitat. Having spent considerable time in that habitat, I thought I knew it quite well.

But it turns out I hardly know it at all.

For example, I thought I knew its vocalizations, both song and call. I've spent the last four winters in Central American pine-oak forests looking for wintering Golden-cheeked Warblers, and saw and heard this hummingbird all the time.

But a couple of days ago, while banding birds at the pine-oak banding station in Montecristo national park, El Salvador, I recorded a hummingbird song that I was not familiar with. I knew the hard, metallic chip that males produce constantly this time of year. But the insect-like chirp that I recorded on Tuesday is very different. Here it is:


Here's another, shorter fragment of the same bird, singing the same song.


And here's a short fragment (of presumably the same bird) with rather typical feeding calls. These I was already familiar with.


Alexander Skutch, in his fascinating book on birds of the region called Trogons, Laughing Falcons, and Other Neotropical Birds, writes about White-eared Hummingbird singing leks he studied in Guatemala. He notes something that was new to me, but immediately 'clicked' when I read it. I'll quote at length:

Perhaps the most typical note of the male White-eared Hummingbird is a low, clear tink tink tink, sounding like the chiming of a small silver bell. This was the note that I first heard and prefer to remember. Some individuals toll their tiny bells very rapidly, others more slowly and deliberately. But as I became familiar with more and more White-ears, scattered over miles of mountainside, I was surprised by the variance of their voices. Many individuals consistently uttered notes so different from the usual clear tinkle that I did not recognize them as belonging to White-ears until I laboriously stalked the birds and watched them calling. These notes were dull and flat, devoid of the clear timbre characteristic of the species, or high and squeaky, or low and melancholy. One White-ear that I often visited repeated rapidly a harsh, metallic click, a buzz almost painful to hear.

Equally unexpected was my discovery that all members of an assembly sang in much the same way but differently from those in other assemblies.  If one bird of a group repeated a silvery tinkle, his neighbors would be found to do the same; if I was attracted to an assembly by chirping notes, this was the prevailing tune.

from Alexander F. Skutch, Trogons, Laughing Falcons, and Other Neotropical Birds, 1999, Texas A&M University Press, College Station, Texas, USA.


The insect-like song that I recorded is not described in Howell's guide to the region, nor in Sibley's or Kaufman's guides to North American birds. In fact, apart from Skutch's perceptive observations quoted above, most bird guides tend to give succinct, seemingly complete descriptions of its vocalizations. To my ears, none of the other White-eared Hummingbird vocalizations represented in xeno-canto at the time of writing sound like my bird. And although only a single bird can be heard in my recordings, I sometimes heard another one there, duetting with a similar song.

Monte Uyuca

Our first outing at our last field site, Monte Uyuca near Tegucigalpa, proved successful today: we found no fewer than four Golden-cheeked Warblers. Three of them were in today's large flock, all three males. It pays to observe plumage details, for today's first goldencheek had no streaks at all on the undertail coverts, while bird number two was distinctive because the black on the breast was considerably less than on the first bird. The third bird finally was seen in close proximity of the other two. All three birds had black throats, black chins and black upperparts - and thus were adult males - but differed subtly from each other in the amount of streaking in various places.

Also exciting was an observation of three Ocellated Quails that Kashmir flushed almost from under his feet. The birds flew a short distance and landed, but could not be found again. As I mentioned in the previous post, this is a species that I had never seen or heard before. This year we're registering it in two different places.

The hummingbird at the top is a common bird in pine-oak forest, and we see it all the time. Today we had an opportunity to photograph it up close and personal. This is a male White-eared Hummingbird.

This spectacular butterfly was another exciting find. It's called Red-lead Fiestamark; this is a male. It's very small, and very beautiful. I had never seen one before.

Today's large flock had no fewer than 66 individuals representing 25 species. Besides Golden-cheeked Warbler, those included Greater Pewee, Blue-headed Vireo, Wilson's Warbler, Crescent-chested Warbler, Townsend's Warbler, Yellow-backed Oriole, Spot-crowned Woodcreeper, Dusky-capped Flycatcher, Hepatic Tanager, Slate-throated Redstart, Olive Warbler, Golden-olive Woodpecker, Hairy Woodpecker, Rufous-browed Peppershrike, Flame-colored Tanager, Black-throated Green Warbler, Hermit Warbler, Yellowish Flycatcher, Northern Flicker, Warbling Vireo, Black-and-white Warbler, Bushy-crested Jay, Steller's Jay, and Brown Creeper.

At one point, the flock broke in two, with orioles, jays and most woodpeckers going one way, while the smaller species went another way. Later, both parts seemed to merge again, forming this rather large mixed flock.

After we were done with the field work this morning, we continued on the same road to look for tomorrow's location. For hundreds of meters, there wasn't a bird to be seen or heard - all had converged into this mega-flock. Then we found a small pocket with some birds about a kilometer away, including an immature male goldencheek. This was around a construction site. Tomorrow we will go to a slightly different area along the same road.