Belize: Chan Chich New Year Dec 28, 2008—Jan 03, 2009
Posted by Paul Wood
Even before human-induced climate change became a concern, subtle seasonal shifts were always a factor affecting the number of bird species and individuals in a given locality. In this part of the world, the major factor influencing food supply is the annual rainy season. It could be early, late, abundant, poor, or even fail in some years. The dry season is also the trigger for important events in the annual cycle, inducing leaf fall, and thus subsequent leaf renewal and insect abundance. Upon losing their leaves, many shrubs, vines, and trees burst into flower producing a temporary boom in resources for nectar feeders. Pollination success or failure will determine how much fruit is available for birds and other animals later in the cycle.
Unfortunately, due to lack of monitoring and study, our understanding of these ecological intricacies was poor even before climate change, thus undermining our ability to distinguish the effects of global climate change from the "normal" seasonal vagaries. Whatever the cause, this year an enduring high pressure system brought us stable weather throughout the trip, with only a few light showers that fell mostly at night. In contrast to last year, the sun shone daily, and the snowbirds got the golden rays required to keep the winter blues at bay.
In the past, we had to wait to get to the lodge to see our first Ocellated Turkeys, one of the emblematic species at Chan Chich. However, at least locally, turkeys have become so common that they wander the open fields at Gallon Jug in small droves, and today it is one of the first species to send people scrambling for their binoculars after descending at the airstrip. Indeed, Ocellated Turkey displaced Great-tailed Grackle as the most numerous bird on the Christmas Bird Count we were to take part in on New Year's Eve. The lack of hunting in the area over the last 20 years has clearly benefitted these large game birds, and others such as Great Curassow and Crested Guan—both of which we were to record daily.
As tradition demands, our first day began with coffee at the lodge beneath the African tulip tree, whose large orange blooms produce copious amounts of nectar during the dry season. Just as many of us need our caffeine fix, many birds start the day with a sugar fix, and so this is a natural congregation point for both. Two of Chan Chich's flashiest birds, Green Honeycreeper and Chestnut-colored Woodpecker, are among the native junkies and were the first attention-grabbers of the day.
The tulip tree, however, had started flowering earlier this year and many of the flowers had seeded, while those remaining seemed to have passed their peak of nectar production. This was the first sign that that the dry season had started early this year, and the numbers of usually common nectar feeders, such as Rufous-tailed Hummingbird, were appreciably lower. The frequent bouts of vicious combat between male Green Honeycreepers, sometimes tumbling to the ground in undignified squabbles, also suggested that nectar supplies were in decline.
After breakfast, the first of our walks down to the suspension bridge produced Lineated and Pale-billed woodpeckers, a variety of forest flycatchers, ant-tanagers, greenlets and warblers, and a busy group of Dot-winged Antwrens. An obliging White-necked Puffbird (a bird often missed due to its habit of sitting quietly in the canopy) was a highlight.
While the morning was off to a good start, the afternoon had some juicier treats in store. We walked a little way down the road from the plaza to get better looks at spider monkeys that Brian had seen crossing the road. Monkeys are one of the daily delights at Chan Chich, and after watching them interact for a while, few are left in doubt as to our own origins. Ducking into the forest along the King's Tomb trail, I began my annual search for the elusive Tody Motmot—a search that sometimes goes on for several days. We had gone no more than 30 paces when, on one of my first scans of the undergrowth, I spotted a Tody Motmot sitting typically motionless on a small shrub. This was too good to be true, but the whole group got looks through the scope while I was recovering from my own disbelief. Only a few paces further on, while the group was still exchanging impressions, I looked up to see a Great Tinamou foraging in the leaf litter on the hillside. Great Tinamous are notoriously shy, more often heard than seen, and, when they are seen, usually disappear quickly into the undergrowth or explode into the air leaving branches quivering. This bird, however, seemed less interested in us than in continuing its foraging, and the group got rare views, back and front, of another usually inscrutable species. Chan Chich was working its magic, and this was a highly encouraging start.
Indeed, one of the outstanding characteristics of tropical areas is the large number of fruit-eaters. During the non-breeding period, many insectivorous species change diets and become heavily dependent on fruit, too, so that fruit crops become extremely important to many species to see them through the drier months when insects are harder to come by. This year, and perhaps related to the early onset of the dry season, fruit seemed to be in short supply, at least in the Chan Chich area. This most likely explains the scarcity of big fruit-eaters, particularly pigeons, large parrots, and toucans. Normally common Short-billed Pigeons were rare, and we had to wait until our Gallon Jug trip to get good looks at the gorgeous Keel-billed Toucan. Trogons were seen daily, but numbers were down, as were numbers of Red-lored Parrots, while Mealy and White-crowned parrots were also decidedly rare. As evidence of the problems faced by parrots, one afternoon we watched a pair of Mealy Parrots patiently stripping an unripe fruit oozing with sticky toxic resin in order to get to the precious kernel inside. This laborious and messy process cannot have been the parrots' first choice! On the up side, the uncommon Brown-hooded Parrot was seen daily in the plaza, probably the same group of eight or so birds each day.
I should point out that, just because fruit was scarce in the Chan Chich area, it was not necessarily scarce over the whole of the forest. Brian, for example, reported good numbers of fruit-eaters from his trip to Tikal, just the week before. Fruit-eaters must often move over large distances to locate food supplies, and this is one of the many reasons that conservation areas in the tropics must be large—large enough to allow birds to move when resources fail locally. Hundreds of thousands of acres are required to maintain this dynamic.
The smaller, spiffy manakins, both Red-capped and White-collared, were however, able to find sustenance from fruiting shrubs behind the plaza, and White-collared were also much in evidence along the Chan Chich river. The Ochre-bellied Flycatcher, however, normally common and principally a fruit-eater, was also scarce, suggesting that fruit may also have been scarce for some of the smaller fruit-eaters, too.
While scarcity of fruit locally is unlikely to provoke a disaster if birds can move to more favorable areas, more worrying to me has been the persistent decline of ant swarms over the last several years. Swarms of army ants provide an essential resource for many species, particularly woodcreepers, ant-tanagers, Gray-headed Tanagers, and Ovenbirds, while many other species, including migrants, take advantage of them opportunistically. The disappearance of ant swarms would therefore be disastrous for many forest-dependent species. Since army ants are predators on arthropods living in the leaf litter and under the bark of trees, the lack of ant swarms could point to a more worrying, general decline of the leaf litter fauna. This fauna also has other important ecological functions in terms of soil enrichment, decomposition, and pollination, as well as providing food for wildlife. Indeed, some entomologists have suggested that a warming of the climate by just a few degrees could disrupt the breeding cycle of tropical insects in general and lead to ecosystem collapse over wide areas.
We found only a couple of small ant swarms, poorly attended by birds, and our only Barred Woodcreeper seemed rather lethargic and not to be having much luck. While we had no trouble finding the Tawny-winged Woodcreeper away from swarms, we missed the Ruddy Woodcreeper, a swarm specialist, completely, and Gray-headed Tanagers were also scarce. Ivory-billed Woodcreepers were also lower in number over the week. Among the woodcreepers, only the little Olivaceous, which is not tied to ant swarms, was common.
Mixed species flocks are a staple for birders in the Tropics during the non-breeding months. Those that follow ant swarms are limited to the forest floor and undergrowth, but other suites of species specialize in the understory and in the canopy. Understory flocks of Red-crowned Ant-Tanagers and Tawny-crowned Greenlets, two species that for unknown reasons are most often found together, were fairly common. The curious Eye-ringed Flatbill was seen several times with these flocks. Greenlets as a group, though they are vireos, perform much the same function in tropical areas as chickadees in temperate zones, often forming the core of a flock and gathering other species around them. Lesser Greenlet, another common bird, takes over from the Tawny-crowned Greenlet in the canopy. One of these flocks, along the bajo trail, produced a rare Green Shrike-Vireo, thanks to the sharp eyes of Connie.
Another "pied piper" in the canopy is the Black-throated Shrike-Tanager. Males and females gather their own flocks around them, one individual to a flock, by acting as a sentinel and warning flock members when predators are near. However, they occasionally use these warnings as a trick to scare a flock member from hard-earned, potentially juicy prey, which they swoop down to gobble up themselves. Their scolding clucks and high-pitched whistles are a sure sign that a mixed flock is in the vicinity. Males bear a remarkable resemblance to Black-cowled Orioles, and this mimicry is akin to the bird dressing as a wolf in sheep's clothing—they would be at home amongst the world's financiers! We had our share of these flocks, often accompanied by fast-moving Plain Xenops, and cool warblers such as Blue-winged and Worm-eating, the latter being seen well several times. In general, however, my impression in recent years has been that these canopy flocks are less frequent and smaller than before.
The stable weather worked in our favor for birds of prey, and a pair of Black-Hawk-Eagles, as well as an Ornate, displayed over the lodge on New Year's Eve. Their excited calling truly evokes the unbridled freedom of the air. Another star among the birds of prey was the White Hawk—a pair of which seem to have taken up residence around the lodge. We had several close encounters and wonderful scope views of this exotic-looking hawk during the week. King Vultures were seen on three days, and a black phase Hook-billed Kite at Laguna Seca was another highlight.
Laguna Seca was a little disappointing for its lack of waterbirds, though Jacanas are always an elegant sight, tiptoeing across the lily pads. Just as we were leaving, however, we stopped to look at a pair of Least Grebes spotted by Brian. He walked down to the lakeside with some group members, and, instead of Least Grebe, found himself staring at a Sungrebe—and just as we were getting settled for our trip back to the lodge. After rapid "unpacking" of the vehicle, we got some good looks at this very skittish bird that is not a grebe at all, and only dives to escape notice.
Trish's Hill, a trail that leads to a natural "mirador" of the Chan Chich valley, produced a couple of magic moments. The first was a female Lovely Cotinga, spotted by Brian, on the 31st, and an irate covey of performing Spotted Wood-Quail was a fitting memory for our last afternoon at Chan Chich.
Sightings of nightbirds were scarce. A Central American Pygmy-Owl found by Brian along the Logger's Trail was our best owl, and we disturbed a roosting Barn Owl at Laguna Seca—both of these seen in broad daylight, of course! However, our night-drive did produce some spectacular close-ups of Northern Potoo at only a few feet from the open-top truck.
All in all, our "score" of 191 species was above average for the end of year trip and proves that Chan Chich continues to be one of the top birding spots for reliability in the American Tropics, despite the underlying uncertainties of seasonal and global climate change. No matter how many birds make up the final count, however, Chan Chich never fails to produce memorable birding in idyllic surroundings.