Geography And Climate
Located at the southeastern tip of the Yucatán Peninsula, Belize is the only English-speaking country in Central America and one of the few in all of Latin America. At 16º to 18º30' north latitude and 87º30' to 89d5' west longitude, it is well within the New World Tropics. The Caribbean Sea lies to the east, Guatemala to the west and south, and Mexico to the north. Belize is about 180 miles (290 km) north to south and 65 miles (105 km) east to west at its widest point, with a land area of 8,867 square miles (22,965 km2). It is only slightly larger than El Salvador, Central America's smallest country; yet with only 250,000 people, it has only one-thirtieth of El Salvador's population.
Belize has a broad, flat coastal plain, broken only by the relatively low-lying Maya Mountains in the south and some low hills in the northwest. Belize's highest peak, located in the southern Maya Mountains, is only 3,688 feet (1,124 m). Composed of granitic, metamorphic, and volcanic rocks, overlain in some areas by limestone, the Maya Mountains rise abruptly from the coastal plain, then slope gradually to the west. The Vaca Plateau, for example, which lies west of the Maya Mountains, has an average elevation of about 1,600 feet (490 m). A number of rivers drain the Maya Mountains watershed, most prominent among them being the Raspaculo-Macal-Belize river system, the Sibun River, North and South Stann Creek, and the Sittee River in the north, and Monkey River, the Deep River, and the Rio Grande in the south. North of the Maya Mountains are the New River, with its network of bird-rich lagoons, and the Rio Hondo, which defines much of the Mexico-Belize border. South of the Maya Mountains watershed are the Temash and Sarstoon rivers, the latter defining Belize's southern border with Guatemala.
East of the coastal plain lies the world's second-longest barrier reef, which begins just north of the Belize-Mexico border and extends south nearly the length of the country, then discontinuously east to include the Bay Islands of Honduras. Along and within the reef are hundreds of small- to moderate-sized cayes (pronounced "keys") plus the much larger Ambergris Caye, which is actually a long, thin peninsula extending south from Mexico for 17 miles (27 km) just inside the reef. Beyond the barrier reef are three coral atolls: Lighthouse Reef, Turneffe Islands, and Glovers Reef.
Belize has a tropical climate. Monthly mean maximum temperatures range from 82.5ºF (28ºC) in winter to 91.5ºF (33ºC) in summer. Although winter lows may occasionally dip into the high 50s (midteens), and even lower at high elevations, frost is unknown. Belize has a distinct rainy season, with most of the rain falling in July and August, then gradually tapering off through December. The rainy season begins abruptly with several days of heavy rain, typically commencing in late May or early June, whereas the onset of the dry season is gradual and virtually imperceptible. The rainy season is characterized by moderate to strong trade winds that blow from the east. By early winter, the trade winds and their associated thunderstorms give way to mild westerlies and occasional "northers," cold fronts that sweep through North America with their southern tip often extending into the Tropics. With the northers come cooler temperatures and modest rains of longer duration.
Mean annual rainfall varies dramatically from north to south, with less than 45 inches (110 cm) in the far north and more than 160 inches (400 cm) in southernmost Belize. Although no official record exists, it is likely that higher elevations in the Maya Mountains receive in excess of 180 inches (460 cm) of rainfall annually.
For its size, Belize possesses an impressive diversity of plant and animal life. Nearly 75% of the country's land area is still dominated by natural vegetation, owing largely to Belize's small human population and relatively strong conservation ethic. In addition, Belize possesses a complex underlying geology, a wide variety of soil types, and a strong north-south cline in precipitation. These factors, coupled with its relatively varied topography, all contribute to a greater variety of vegetation types than would otherwise be expected in a country this size. Approximately two-thirds of the country is covered with forests in various states of maturity. Dominant among these is subtropical, moist, semideciduous broadleaf forest, with pine woodland and savanna composing a much smaller proportion. Nearly half of the country's land and adjacent waters have achieved Protected Area status as forest reserves, wildlife sanctuaries, national parks, or other similarly designated areas.
Natural vegetation along much of the coastal plain, except Corozal District and all but northeastern Toledo District, comprises open pine woodland and savannas and seasonally wet meadows. Mangrove forests line much of the coastline and the majority of cayes. The northern half of the country is dotted with freshwater marshes and lagoons. These are virtually lacking in the south. On its two highest peaks, Belize has a very limited amount of cloud forest.
The habitat types presented below are necessarily broad and relatively few. They are not intended to reflect in any significant way a botanist's view of the world, but more a bird's view of its world. To specify more narrowly defined habitats would be unnecessarily complex and would likely exceed our current knowledge of what actually limits most species' distribution across or within the various vegetation zones (see discussion in the section "Habitat").
At the top of 3,675 feet (1,120 m) Victoria Peak and 34 miles (55 km) to the southwest atop of Belize's 3,688 feet (1,124 m) unnamed highest peak, unofficially dubbed Doyle's Delight, are small stands of dwarf forest, perhaps closest in type to elfin woodland and palm brake cloud forest. Because these peaks are enveloped in clouds much of the year, the vegetation is almost completely covered with mosses and ferns, and the underlying soil and rocks are covered additionally with sphagnum, club mosses, and lichens. The tallest trees are typically no more than 20 feet (6 m) tall on Victoria Peak and 30 feet (9 m) tall on Doyle's Delight.
Submontane Broadleaf Forest
The forest cover in most of the Maya Mountain range roughly above 1,300 feet (400 m) is dominated by evergreen trees 80 to 120 feet (25 to 35 m) tall with buttressed trunks. The forest is structurally complex, with a high incidence of epiphytes and lianas, and a substory dominated by tree ferns, a variety of palms, and other shrubs and small trees of low to moderate stature. Because the canopy is closed, little light penetrates to the forest floor, and understory vegetation is sparse.
Lowland Broadleaf Forest
This forest type, the dominant forest cover in Belize, is similar to, but less luxuriant than, forests at higher elevations. It typically contains more dry-season deciduous tree species, fewer epiphytes and palm species, and few if any tree ferns in the substory. As in the submontane forest, the understory is sparse; however, toward the end of the dry season, the leaf litter on the forest floor can become quite dense. In the south, the lowland forest, like that at higher elevations, has a closed canopy with tree height averaging in excess of 100 feet (30 m). North of the Maya Mountains, the forest is both drier and of smaller stature, with many more deciduous species and an average canopy height seldom exceeding 80 feet (25 m) away from the major rivers. The canopy is more open, allowing for a denser understory.
Bajos, a specific type of seasonally flooded lowland broadleaf forest, are relatively numerous in the north but become increasingly scarce southward. Because bajo forests are structurally similar to other types of lowland broadleaf forest and their avifauna, for the most part, is similar, they are not classified as a separate habitat type here.
Submontane Pine Woodland
The Mountain Pine Ridge, a 125-square-mile (325 km2) westward extension of the northern portion of the Maya Mountains, has underlying soils that are predominantly sandy, resulting from decomposed granite. Here, the broadleaf forest is replaced by an open pine woodland (primarily Pinus caribaea) with a smaller component of oaks. In many areas the understory is relatively sparse, with grasses predominating, but in recently burned areas a low-growing, nearly impenetrable tangle of ferns (Dicranopteris sp.) predominates.
Lowland Pine Woodland and Savanna
In the coastal lowlands from the Mexican border in northern Orange Walk District, somewhat discontinuously south to northeastern Toledo District, the terrain is dominated by a pine woodland similar in many respects to that in the Mountain Pine Ridge. As in the pine ridge, pines dominate the landscape and are typically found in close association with oaks. However, the understory is much more varied and complex. In many areas, a variety of shrubs and grasses compose the understory. In other areas, palmettos, calabash, and sedges are the dominant understory species. The woodland ranges from relatively dense to open and savanna-like.
Seasonally Wet Meadows
Pine woodland transitions to savanna, and savanna to wet meadow, in many areas almost imperceptibly, in others quite abruptly. Together, the meadows, savannas, and woodlands form a complex mosaic that, although quite different at the two extremes, are often almost impossible to delineate as separate vegetation types because of the many broad transition zones. Extensive seasonally flooded areas with few or no trees are considered separately here because of their distinctive avifauna.
Marshes and Lagoons
Freshwater marshes and lagoons dot the lowland landscape north of Stann Creek but are much less frequent in the south. They range from small ponds with emergent grasses, sedges, rushes, and cattails to expansive shallow lagoons. Unlike seasonally wet meadows, marshes are flooded year-round, have taller emergent vegetation, and are usually found in association with ponds or lagoons. Lagoons may be essentially isolated bodies of water, especially those just back of the coast, or they may be wide areas in sluggish rivers (e.g., New River Lagoon). They are usually shallow, often with seasonally fluctuating water levels. Poorly drained lagoons, such as those at Crooked Tree, have a remarkably rich avifauna that changes compositionally along with the water level through the year. It is these lagoons that attract impressive numbers of waterfowl, waders, and shorebirds in the dry season.
Mangrove and Littoral Forests
Mangroves, especially the red mangrove (Rhizophora mangle), line the coast in many areas and may extend some distance inland along major rivers. They are also a significant component of many cayes. The "drowned" cayes are mangrove cayes with no dry land. Mangroves are essential in stabilizing coastlines and serve as important nurseries for many fish species. Behind the red mangroves, on higher land but still within the highest reaches of the tidal zone, are several larger unrelated species that are collectively referred to as black mangroves and white mangroves, depending on their growth form. Above the tide line, mangroves are replaced by littoral forest, which reaches its greatest expression on the cayes. Dominant tree species in the littoral forest vary from 20 to 40 feet (6 to 12 m) tall and typically have broad, tough, leathery leaves.
Humans have altered the native landscape of Belize in many and various ways. Such humanaltered habitats range from towns and villages, with their trees, lawns, and parks, to agricultural fields, orchards, rice fields, and aquaculture ponds. Recovering forests are often the result of human activities, but at some point in their recovery, they become "natural" habitats again. Human-altered habitats vary from virtually unvegetated, recently disked fields to vegetationally complex and dense second-growth scrub. Each has its own complement of birds, and some, such as rice fields, and aquaculture ponds at harvest time, can attract a remarkably diverse avifauna.
With its extensive tropical forests, pinelands, species-rich lagoons, and countless cayes along its barrier reef, Belize has an avifauna approaching 600 species. As such, it serves as an ideal introduction to tropical birding, especially for English-speaking tourists.
As expected for a country located at 16º to 18º north latitude, its avifauna includes both North Temperate and tropical elements in roughly equal proportions. Of the approximately 573 species reliably recorded in Belize through mid-2002, a little more than half do not reach the Temperate Zone and are thus truly tropical. Of those that do, 80% are migratory, reaching or passing through Belize only in winter or during migration.
The terms "resident" and "migratory" are somewhat relative. A number of non-migratory species turn up, at least occasionally and sometimes regularly, on the cayes where they are clearly not resident. Others may be resident in one part of Belize and seasonal in another. For presumed residents, we know little about seasonally fluctuating numbers. For example, many species follow seasonal food supplies. Some hummingbirds move considerable distances at certain seasons timed to correspond with the blooming period of favored plants. Scarlet Macaws are considered to be resident west of the Maya Mountains but seasonal (January to April) east of the Maya Mountains. Hookbilled Kites are thought to be essentially resident throughout their range from northern Mexico to central South America, yet thousands can be observed migrating south in coastal southern Belize every autumn. Where are they coming from? Where are they going? No one knows. Green Shrike Vireos are common in the dry season yet inexplicably scarce in the rainy season. Is this because they largely vacate much of Belize during the rainy season? Or is it because they are much less in evidence when they are not singing? Perhaps it is a little of both. A few species--such as Slate-colored Seedeater, Blue Seedeater, and Grassland Yellow-Finch--are nomadic, appearing in an area and breeding for one to several seasons, then disappearing.
Truly migratory species have precisely set biological clocks. With few exceptions, Black-and-white Warblers appear every year in the third week of July, Golden-winged Warblers in the third week of August, and Palm Warblers in the third week of September. An individual seen a mere two weeks earlier would be noteworthy, and one seen even a week ahead of schedule would be considered early. Most species migrate at night, presumably to minimize predation, but a few, like migratory hawks, swallows, Chimney Swifts, and Eastern Kingbirds, migrate during the day, and at least one, the Dickcissel, may migrate both at night and during the day.
Whereas migrants could turn up in almost any habitat, most of the resident avifauna is much more habitat specific. Of three broadleafforest species in southern Belize, the Nightingale Wren is found exclusively in hill country (karst limestone hills, Maya Mountains), the Western Slaty-Antshrike only in coastal lowlands, and the Orange-billed Sparrow in both. A number of species are confined to the pinelands. In fact, one species, the Grace's Warbler, is seldom seen outside a pine tree! Although most pineland species are found in both the lowland pine savannas and the Mountain Pine Ridge, a few such as the Ladder-backed Woodpecker are confined to the lowlands, whereas others such as Greater Pewee are confined to the uplands, even though the dominant plant species in both areas is the Caribbean pine.
A few bird species seem to be confined not by gross habitat or topographical parameters but by some other, as yet unknown factor. The Azure-crowned Hummingbird is found in a wide swath across central Belize that includes both lowland and upland pine woodlands as well as upland broadleaf forest. But it is not found in lowland pines and upland broadleaf forest (or any other habitat) north or south of this seemingly arbitrary line. The Plumbeous Vireo is found in the Mountain Pine Ridge (pine forest) and at higher elevations in the Maya Mountains (broadleaf forest). Yet it does not appear to be confined elevationally, because a small population also persists in the lowland pine savannas of Stann Creek District.
Many bird species have dramatically increased in number in the 39 years since the publication of Steve Russell's Distributional Study of the Birds of British Honduras. Nearly all of these are birds associated with cleared land, urban areas, second-growth scrub, and manufactured wetlands such as rice fields and shrimp farms. At the same time, although not as apparent, all birds of mature broadleaf forest, littoral forest, and mangrove forest have surely decreased in number as man-made habitats have gradually replaced Belize's original forested habitats. While grackles, cowbirds, seedeaters, and some species of pigeons and doves have proliferated as the result of human activities, many forest birds--especially those requiring large territories, like birds of prey--and colonial seabirds, especially terns, have become perilously scarce. On the other hand, migratory waterfowl, shorebirds, and waders, including the Jabiru, have benefited at the expense of grassland and savanna species such as the Black-throated Bobwhite, Botteri's Sparrow, and Grasshopper Sparrow. Several terns (Roseate, Bridled, Sooty, and Brown Noddy) have been nearly extirpated as breeding species in Belize since the mid-1960s, and one, the Black Noddy, was extirpated long before the 1960s. Some birds of prey such as Ornate Hawk-Eagle and Harpy Eagle are almost certainly scarcer now than 40 years ago, although the early data (before the influx of birders) on these species are too sparse for any meaningful comparison.
On the other hand, several now-common species (Double-crested Cormorant, Blackbellied Whistling-Duck, Red-billed Pigeon, and Bronzed Cowbird) were rare in the early 1960s, and the White-winged Dove and Yellow-faced Grassquit were yet to be recorded. Other species, not yet common but clearly on the increase, include American White Pelican, Glossy Ibis, Fulvous Whistling-Duck, and White-winged Becard. All of these species are likely responding to a changing landscape that favors them at the expense of other species. As of mid-2002, the Shiny Cowbird has not yet been recorded, and the Eurasian Collared-Dove has been recorded only twice. These two species are rapidly expanding their ranges into Central and North America and may well be common, at least locally, in Belize within the next couple of decades.
Successful bird identification is directly related to the time spent observing an unknown bird, not time spent perusing the book for vital information. The layout of this book is designed to facilitate the identification process by minimizing the time spent consulting the book while the bird is under study. Ideally, the book should not be consulted until after the bird has been thoroughly studied, notes taken, and sketches made. The more time spent studying the bird, not the book, while the bird is in view means more time absorbing important information about the bird.
When consulting the book, knowing what family or group the bird belongs to will save a lot of time in narrowing down the choices. For the beginner, the first step then is to become familiar with the arrangement of the families and species (see the sections "Taxonomy" and "Nomenclature," below), then the family and group characteristics (see "Family and Group Headings"). Bird terminology can be confusing, if not overwhelming, to the person just starting out. Understanding plumage sequences and molt is vital to the identification process (see "Plumage and Molt"), as is an understanding of the terminology used to describe the various parts of a bird (see "Bird Topography").
The advanced birder can skip these sections. For the more skilled birder who is more likely to know at the outset the family or group to which a puzzling species belongs, this book has a feature called "Things to note" that is designed to assist the observer, not in determining immediately which species the bird is, but in noting key field marks to look for while the bird is still under observation. After the bird is gone, and with this key information in hand, successfully identifying the species should be relatively straightforward.
The class Aves is divided into orders, and the orders into families. Within each family are genera, and within each genus are the species. For a person just beginning to learn the birds, this grouping may seem somewhat capricious. For example, why are New World vultures grouped with storks instead of hawks? American Coot with rails instead of grebes? Eastern Meadowlark with the blackbirds? And Dickcissel with the buntings? Although taxonomists may disagree on some aspects of how birds should be classified, there really is a considerable amount of scientific evidence to support the manner in which birds are grouped. Birds thought to be the most primitive are listed first, and the most recently derived last. Species are grouped into families, and families into orders, based on shared morphological, biochemical, behavioral, and genetic characters. Although a beginner may lament that birds are not listed alphabetically or arranged according to some color scheme, any veteran can tell you that once you have a fundamental understanding of avian classification, the grouping of species according to their "phylogenetic" relationships is useful in developing a basic framework for bird identification. Having the tyrant flycatchers all placed together makes a lot more sense than having the closely related Great Kiskadee and Boat-billed Flycatcher grouped with the K's and F's, respectively, or the quite unrelated Blue-gray Tanager and Blue-gray Gnatcatcher placed together because of their similar color.
To help the user of this book better understand the higher-level groupings of birds, brief paragraphs highlighting the shared traits of each family are included in the text. Ibises and spoonbills are grouped together in the family Threskiornithidae because of certain shared characters that are believed to be genetically linked. Note that in the world of animals family names always end in "-idae."
Not surprisingly, in a field in which we still have so much to learn, there are several widely accepted classification schemes for birds, some quite disparate at the higher taxonomic levels. In this guide, the convention adopted by the American Ornithologists' Union (AOU) is used because that is the convention most familiar to New World ornithologists and birdwatchers, not because it is any more "correct" than other schemes.
Like all living things, birds have a scientific name comprising a genus name and a species name. The first letter of the genus is always capitalized, and the species name is never capitalized (e.g., Ara macao, the Scarlet Macaw). Some species are further divided into subspecies. These have a third name, also never capitalized. The scientific name is always written in italics. Thus the subspecies of Yellow Warbler that breeds in Belize, known as the Mangrove Warbler in English, is Dendroica petecbia bryanti.
Because birding enjoys a popularity among amateurs that is without parallel in any other scientific endeavor, and most amateur birdwatchers do not know the scientific names of birds, their English names have become increasingly standardized to eliminate confusion. The AOU has adopted a rigorous standard for English name usage to thwart the proliferation of names in field guides, handbooks, and other publications. Exceptions remain, however, for many species that range well beyond the geographical area covered by the AOU. The cosmopolitan species Ardea alba, which is variously known as Great Egret, Great White Egret, American Egret, and Common Egret, has been dubbed "Great Egret" by the AOU. Other conventions, especially in the Old World, use the name "Great White Egret." Again, the latter is no less "correct" than the name "Great Egret."
Plumage and Molt
Many species of birds change their appearance with age or the seasons. They do this through a combination of changing their feathers (molt) and feather wear. When molt results in a plumage that is recognizably different from the preceding plumage, the different plumages are given specific names that refer to their age-related or seasonal set of feathers. Recognizing the plumage that a bird is in can be a convenient means of determining the bird's age or sex and in some cases aids greatly in determining the identity of the species.
Various terminologies for plumage and molt have been proposed over the years, but the one proposed by Humphrey and Parkes (1959, 1963) has become the one most widely used by authors of field guides and handbooks in the Western Hemisphere (e.g., Howell and Webb 1995; National Geographic Society 1999; Sibley 2000). Very recently, a modified version of the Humphrey-Parkes system has been proposed by Steve Howell and others. Although not yet published in late 200?, this modified, simplified approach is eloquently summarized by David Sibley in his excellent new book Sibley's Birding Basics (2002). The first true plumage of contour and flight feathers is the juvenal plumage. It grows in over the feathers of the downy young. The bird in this plumage is referred to as a juvenile (note the different spelling). Some molt out of juvenal plumage almost immediately; others retain juvenal plumage until after they have migrated to their wintering grounds. Through either a partial or a complete replacement of its feathers, the juvenile molts into its first basic plumage. In some species, the first basic plumage is indistinguishable from that of the adult; thus, the only recognizable postnatal plumages are the juvenal plumage and formative, or adult-like plumage (e.g., Orange-billed Sparrow).
Many species replace at least some of their feathers twice a year, with each corresponding plumage being recognizably different. These plumages are referred to as the basic plumage and the alternate plumage. For most species, the alternate plumage is worn during the breeding season, and the basic plumage is worn the remainder of the year (Sanderling, Chestnut-sided Warbler). Some species have a very protracted basic plumage (Royal Tern); others a very brief basic plumage (Blue-winged Teal).
Alternate plumage may be attained in a variety of ways. Very few species molt all of their body and flight feathers during the pre-alternate molt. One exception is the male Bobolink, which undergoes a complete transformation from the rather dull-colored basic plumage to the gaudy black, white, and buff alternate plumage. Most Temperate Zone species, however, go through a partial molt, often involving only the body, or contour, feathers. An example is the male Scarlet Tanager, which replaces its green body feathers with bright scarlet feathers while retaining its black wings and tail feathers. Many tropical species, on the other hand, retain much or all of their basic plumage through the breeding season, molting only once a year, usually in late summer or autumn.
Still others attain their "alternate plumage" not through molt but through feather wear. The male Blue-black Grassquit, for example, molts into what appears to be a femalelike dull brown plumage after the breeding season. However, only the fragile tips of its overlapping body feathers are brown. These soon wear off, revealing the glossy blue-back feathers of breeding plumage that were there all along, just not visible. This is an interesting strategy that enables many species to transform themselves from a protective plumage of browns and olives into a showy breeding plumage without the significant expenditure of energy required for shedding and regrowing feathers.
In many species the male and female wear different plumages for part or all of the year. Species with distinctive male and female plumages are more prevalent in the Temperate Zone than in the Tropics, and in a few species, such as Black-cowled Oriole, males and females differ significantly in the northern part of their range but are indistinguishable in the southern part of their range. In some species the male and female wear different plumages year-round (Great-tailed Grackle), in others the male resembles the female only in basic plumage (Bobolink), and in still others the male and female are indistinguishable year-round (Melodious Blackbird).
Aging in birds is defined by the progressive sequence of molts leading to the adult-type plumage. Most tropical species and many temperate species molt directly from their juvenal plumage into adult plumage within one to a few months after fledging. The vast majority of these species breed in their first spring. Other species, notably hawks and gulls, require more than one year to attain adult plumage. Some examples of the aging process are as follows:
- Green Jay: Molts directly from downy plumage into a plumage that is indistinguishable in the field from adult plumage. It has no discernible juvenal plumage.
- Orange-billed Sparrow: Has a distinctive juvenal plumage but attains adultlike plumage with its first molt.
- Short-billed Dowitcher: Retains a distinct juvenal plumage through November, then acquires the adult-type alternate plumage by spring, well before the end of its first year. American Redstart: Retains juvenal plumage only briefly, followed by a molt into first basic plumage shortly after leaving the nest. Its first alternate plumage, acquired in spring, is recognizably different from that of the adult (this is especially noticeable in the male). It is not until late in its second summer that the young bird attains adult-type plumage.
- Great Black-Hawk: Retains juvenal plumage through its first year, molts into its first basic plumage in its second year, and molts into its second basic plumage shortly after the beginning of its third year. It does not molt into adult-type plumage until it is nearly four years old.
- Herring Gull: Retains juvenal plumage only for a short period after fledging and, through a process of protracted molts, proceeds through three basic plumages (three years) before molting into adult basic plumage in its fourth year.
In birds that take more than one year to mature, it is often simpler to refer to nonadult birds collectively as "immatures" or "subadults," as opposed to "juveniles," "first basic," "second basic," and so on. This policy has been adopted, where appropriate, in the species accounts.
In a few more challenging species, the plumage that the bird is in, and even the state of feather wear, may be critical to its correct identification (e.g., some shorebirds, gulls, and flycatchers). Many birds, especially small flycatchers in the genus Empidonax, are very similar, and the juvenile of one species may look more like the adult of another species, and an adult with worn feathers may look similar to yet another species with a fresh set of feathers.
Organization of the Species Accounts
Bird identification is often a multistep process and requires practice. Birds do not always sit still. Success often depends on how much the observer can absorb in a short period of time or from a bird mostly hidden in foliage. Knowing which aspects of the bird's plumage, shape, and behavior are important for identification and which are not can be critical for a bird that is only in sight momentarily. Size, posture, and shape, especially bill shape, are often important in determining the bird's family or genus. Plumage patterns are often important in identifying the species, but a bright red breast may be far less important than the presence or absence of a small white mark behind its eye. Subtle differences in bill size or shape can be more important to note than wing pattern. The underwing pattern of an overhead buteo or buzzard may be critical to its identification; the underwing pattern of a falcon may not. Noting the vocalizations of a small flycatcher may be more critical to its identification than the calls of a confusing fall warbler. The species accounts are organized to facilitate this multistep identification process and to aid the user in recognizing key field marks.
Family and Group Headings
Under each family heading is a general description of the characteristics unique to that family. This is the place to go to learn the difference between a warbler and a vireo or between a woodcreeper and a woodpecker. For closely related species within a family, an additional paragraph describes the characters shared by species in the group, as well as their key differences.
The species group may be a subfamily (e.g., the Anserinae, or geese), a tribe (e.g., the Anatini, or surface-feeding ducks), a collection of related genera (e.g., the kites), a specific genus (e.g., the hawk genus Accipiter), or a group of closely related birds within a genus (e.g., the virens group of Dendroica warblers).
Things to Note
At the end of most family or group descriptions is a brief section entitled "Things to note." The purpose of this tool is to allow the observer to spend as much time studying the bird and as little time as possible flipping through the book and memorizing complex details. This is not the place to go to learn how to tell the two dowitchers apart. It is the place to go when studying a puzzling dowitcher to learn which field marks to look for and which to ignore, so that the bird can be identified later--after it has flown. It would take at least several minutes to wade through the intricacies of how to tell a Short-billed Dowitcher from a Long-billed, during which time the bird may flush unidentified. But it only takes a few seconds to note which characters are critical to the bird's identification and which are not. For example, it is not as important to determine the length of the bird's bill as it is to note what plumage it is in, whether the folded wings project beyond the tail, and what habitat it is in. If these items are carefully noted while the bird is under observation, chances are good that the bird can be successfully identified long after it has flown, by referring to the detailed information presented in the species accounts.
Introducing each species account is the species' currently accepted English name and scientific name. These are the names designated by the AOU in the seventh edition of its A. O. U. Checklist of North American Birds (1998), along with the few name changes specified in the 42nd and 43rd supplements to the check-list published in 2000 and 2002, respectively. With few exceptions, subspecies are not given full accounts in the text. A few strikingly different subspecies, such as the "Mangrove" subspecies of Yellow Warbler, and the Myrtle and Audubon's subspecies of Yellow-rumped Warbler, are, however, accorded separate accounts.
In addition to the 573 species reliably reported from Belize, 6 additional species reported but not confirmed, and 1 species not yet reported, are included in the species accounts. They are distinguished from the species generally accepted as having occurred at least once by having their English name placed in brackets. Although the Baird's Sandpiper, Great Black-backed Gull, Great Potoo, Sparkling-tailed Hummingbird, Eastern Phoebe, and Connecticut Warbler may well have been correctly identified within the boundaries of Belize, the evidence thus far is less than convincing (Jones 2002). All have a reasonable chance of turning up in Belize in the future and are included to bring attention to their as yet unconfirmed status. The seventh species, Shiny Cowbird, has not been reported but is rapidly expanding its range and may soon "invade" the country, as it has the northern West Indies and southern United States.
Following the English and scientific name heading for most species is a list of other names. Many Belizeans are not familiar with the standard English names but know the birds by their local Creole, Maya, or Spanish names. Still others have learned the birds from older books that use English names different from those adopted by the AOU. Of the older bird guides, A Field Guide to the Birds of Mexico and Central America (1972), by Irby Davis, easily has the most English names that never found their way into standard usage. Davis's unique names are also provided here for those who are most familiar with his book. Thus, the section on other names includes, where applicable, alternative English names (alt.), names no longer in general usage (arch., for "archaic"), colloquial names (coll.), English names that may be more familiar to birders from the United Kingdom (UK.), names coined by Irby Davis (I. Davis), K'ekchi names (K), Mopan Maya names (M), and local Spanish names (S). Add to this the many "lumps" and "splits" of species over the past several decades. In many cases, such regroupings have resulted in a new English name for one or both of the split species or for the combined form in cases where two species were lumped. For example, the Gray-fronted Dove
is considered by some authorities, but currently not the AOU, to comprise two different species, the Gray-fronted Dove and the Gray-headed Dove. Under this scheme, the bird found in Belize and the rest of Central America would be the Gray-headed Dove, with the Gray-fronted Dove found only in South America. Under "Other Names" for this bird is the entry "Gray-headed Dove (is part of)," meaning that if the two forms are split, the species in Belize would be called the Gray-headed Dove. Conversely, the Black-headed Trogon was once thought to include populations on both the Caribbean and Pacific slopes of Mexico and Central America and was called collectively the Citreoline Trogon. Now birds on the Caribbean slope are considered a separate species known as the Black-headed Trogon, and those on the Pacific slope are still referred to as the Citreoline Trogon. Under "Other Names" for this bird the reader will find "Citreoline Trogon (combined form)," meaning that if the classification scheme in which all populations are considered to be one species is used, the birds in Belize would be known as the Citreoline Trogon.
In addition to descriptions of the bird's plumage and soft parts (bill, eyes, legs, and feet), the identification section includes an indicator of the species' size and frequently includes important behavioral notes when a species' distinctive behavior may facilitate its identification. Before wading too deeply into this section, it is imperative that the reader become familiar with the terminology used to describe the different parts of a bird (see "Bird Topography").
The approximate overall length of each species is given in both inches and centimeters. For simplicity, only one, average measurement is given, rather than a range, and this should be taken into account when considering the stated size of the bird. Most birds have a range in size of about 5% to rarely 10% or more. In many of the larger species (e.g., hawks) and a few smaller ones (e.g., some of the cowbirds), males and females differ significantly in size. In such instances, male and female measurements are given separately. In some birds that spend much of their time on the wing, wingspread is given as well.
Determining the overall length of a bird is problematical. Unlike the measurement of the folded wing, for example, the measured bill-tip to tail-tip of a bird may vary widely, depending on whether one is measuring a specimen in a museum tray or a live or freshly dead bird in the hand. Even the manner of repose of the living bird can greatly affect its overall length. All birds have extendible necks to some degree. Museum specimens may vary greatly in length, depending on the method of preparing the specimen. For this reason, most recent bird guides have used measurements of living birds. Thus, overall length is given only as a rough indicator of a bird's size relative to similar species. For example, the Lesser Yellowlegs is about 9 3/4 inches long; the Greater Yellowlegs approximately 12 inches. Although not precise, and representing roughly the median size for each, these size measurements are a pretty good indicator that the Greater Yellowlegs is a substantially larger bird than the Lesser Yellowlegs, an important field character. Nevertheless, the size of a yellowlegs feeding alone in a shallow pond can be very difficult to determine, even within a range of 2-3 inches. In cases of lone birds like this, other field characters may be necessary to determine the bird's identity.
In the species accounts, special attention is paid to plumage characteristics, which are usually the primary features but by no means the only ones used in bird identification. In species with recognizably different plumages (male vs. female, basic vs. alternate, juvenile vs. adult, etc.), the differing plumage characters of each are given. Also, on the pages facing the color plates are identification notes for each species and plumage that is illustrated. These notes are condensed versions of what appears in the text.
The behavior of a bird can be critical to its identification, especially in species with similar plumages or a confusing variety of plumages. Behavior includes everything from a bird's manner of foraging to its flight characteristics and its posture. In some species such as birds of prey and shorebirds, the identification of birds in flight is called out separately in the species accounts.
The sounds that birds make are often more important than what the birds look like. After all, if the bird is not seen, its voice may be the only clue to its identification. And it is said that for every bird seen, four others are heard only. Learning bird vocalizations is not as daunting as many people believe. Nearly everyone can instantly identify the voices of their friends and relatives on the telephone, even some friends they may not have spoken with for years. Bird vocalizations should be no more difficult to learn than "people vocalizations."
One of the greatest challenges facing anyone writing a bird guide is how to depict bird vocalizations as text. No one has yet devised a method of accurately describing complex sounds in nature through use of the written word. Many techniques have been used, some more successfully than others. Although written descriptions of bird sounds can never match the actual or recorded sounds, they can serve as a learning tool. Even with a recording in hand, most people need to catalog a sound in their memory through verbal associations in order to facilitate the learning process.
No one can be expected to read a vocal description and then go out and recognize the bird the first time he or she hears it. The verbal descriptions, though, should serve as an aid in remembering the sounds heard in the field through association. The use of CDs or tapes as a supplement to this book is strongly encouraged. But they should be used in conjunction with, not to the exclusion of, verbal descriptions.
This guide employs a combination of phonetic sounds and modifiers such as flat, sharp, metallic, hollow, dry, liquid, squeaky, harsh, buzzy, and nasal to describe the tone, clarity, pitch, modulation, and other qualities. In some cases, soundalike phrases are used, such as Chick, see the vireo, chick! for the song of the White-eyed Vireo and hope, nope, and no hope for the sounds the various ground-doves make. If the descriptions given in the text are read immediately after hearing a bird's song in the field or on tape, they should help commit the sound to memory through association.
A word of caution in learning bird sounds from a commercial tape or CD: many species in the Tropics have rather pronounced regional dialects. This is especially true of some groups like the woodcreepers. With few exceptions, tapes of woodcreeper vocalizations made in southern Central America or in South America are of little use in learning what woodcreepers in Belize sound like.
To successfully make the leap from the written word to the actual sounds heard in nature, you will need to know how to interpret these textual representations. I have made liberal use of the standard diacritical marks for vowel sounds found at the bottom of every page in a standard dictionary. If you are not already familiar with these, learn them first. Spacing of notes in a vocal sequence is represented in the following manner: a pause between notes that is noticeably longer than the spacing between other notes is indicated by one or more extra spaces between notes. A "normal" spacing of notes is indicated with a single space between notes. A rapid sequence of notes (for example, a rattle or slow trill) is indicated with a hyphen between notes, and a very rapid sequence in which the individual notes are virtually impossible to distinguish is represented with no spaces or hyphens between notes. Thus, the widely spaced individual notes of the Spotted Woodcreeper are represented as keeoo keeo keeo keeo; the more rapidly paced song of the Green Shrike-Vireo as dear dear dear dear; the short rattle or slow trill of the Common Tody-Flycatcher as d-d-d-dt; and the rapid trill or buzz of the Grasshopper Sparrow as tp tipit zzzzzzzzzzzzzzzz.
But bird vocalizations are a lot more than the relative spacing of notes in a song or call. Songs have rhythm and cadence, pitch and tone, flatness, sharpness, musicality, richness, amplitude, and many other traits. Wherever possible, I have used words and parts of words to describe these sounds. For example, dee represents a higher note than doe;t is a sharper sound than d, and d is sharper than ch or sh. Other words such as "clear," "hollow," "liquid," "dry," "nasal," and "guttural" are standard written descriptions used to portray familiar sounds. Even with all these aids, will you really know what a Black-faced Grosbeak sounds like from the description given in this book? Probably not. But after you have heard the bird and compared what you heard with the description in the book, you should be able to recall at least some of its vocalizations the next time you hear it or read its vocal description a few weeks, or even months, later.
The best way to expand your knowledge of bird vocalizations is to compare an unfamiliar sound with a similar one you already know. At first, this may be difficult, but as you learn more and more, your accumulated knowledge helps considerably in building upon what you have learned. Thus, the rate of learning can be nearly exponential, at least for awhile. If you have the patience and perseverance to get past the early learning stages, it actually gets easier as you go. Having spent the majority of my adult life in California, I noticed when I first came to Belize that one of the vocalizations of the Rufousbrowed Peppershrike reminded me of the rich cascading song of the familiar Canyon Wren, and that the simple call of the Green-backed Sparrow reminded me of an Orange-crowned Warbler's. Whether you are a tourist or a native, a professional or an amateur, you are probably already familiar with many bird sounds. Just as with learning a foreign language, you can build upon this knowledge; use it as a nucleus for expanding your vocabulary of bird sounds.
Vocalizations are traditionally divided into calls and songs; however, this distinction is not as straightforward as you might think, even for the "songbirds," or passerines. Most birds have a more complex vocabulary than that. For example, one vocalization may be a simple "contact" or "location" call. Another may be given when a bird is slightly agitated, yet another when pursuing an intruder, announcing a nearby predator, or defending a nest. Songs may include a dawn song, as well as the "typical" song. Other vocalizations defy classification. For example, the Rufous-browed Peppershrike gives, in addition to its various calls, a complex whistled jumble of notes at various pitches--clearly its song. However, it also gives a very different series of clear, whistled notes that descend the musical scale, as mentioned above. Is this an alternate song? Or does it serve some other function?
The full vocal repertoire of many neotropical species is extensive, but nearly all have one to several characteristic vocalizations that they give frequently. This book does not attempt to present a comprehensive repertoire; instead, the focus is on the more typical utterances. Wherever possible, I have attempted to separate vocalizations normally referred to as calls from those that are considered to be songs. For most passerines, or "songbirds," the distinction is fairly straightforward. But for many other species, this distinction is blurred, and the use of the word "song" for some nonpasserines is not entirely accurate.
Habitats are complex and can be defined in many different ways. They are not discrete units; there is often broad overlap between different habitat types. No single accepted classification system exists. Botanists classify vegetation types according to dominant plant types, vegetation structure, soil type, and underlying topography. Birds, on the other hand, are often limited by a combination of vegetation structure, presence of preferred food plants, absence of certain potential predators, temperature regimes, and other, more subtle parameters. Rarely are bird species confined specifically to one vegetation type. Some are limited exclusively by food type, others by cover type, and still others by competition with similar species or dissimilar species with similar life requirements. Often, these species segregate themselves on the basis of elevation, type of cover, rainfall patterns, or other factors in combination that may not be readily discernible to humans. And these requirements may change with the seasons, according to a north-south, east-west (coastalinland), or altitudinal gradient. Thus, "habitat" necessarily becomes a loose criterion in framing the physical, geographical, and environmental limitations on a species' distribution. It may or may not correspond with the vegetation types defined by botanists. For the broadly defined habitat types used in this book, see the section "Habitat Types".
The section on distribution frames in very general terms the species' worldwide distribution. It provides a broader context for the species' distribution, status, and seasonality in Belize. For example, when pondering a pewee in January, it helps to know that the Eastern Wood-Pewee and the Western Wood-Pewee both winter in South America, thus leaving the Tropical Pewee as the only reasonable choice.
STATUS IN BELIZE
A bird's status in an area includes (1) its geographic range within the area covered (in this case within the political boundaries of Belize); (2) whether it is present year-round or only during a portion of the year; (3) if the latter, in which season of the year it is expected to be present; and (4) its relative abundance. Its geographic range includes only those habitats in which it is expected to occur; thus, a bird "found on the mainland throughout" can be found wherever its preferred habitat is present on the mainland, but it would not be found anywhere on the cayes, even in its preferred habitat.
Thirty percent of the birds in Belize (about 170 species) are present during only a portion of the year. Knowing which species to expect during any given season can be very helpful in the identification process. A waterthrush in July seen too briefly to identify with certainty would be Louisiana; one seen in May would be Northern. The arrival and departure times given in the text reflect the earliest and latest dates the species can reasonably be expected in Belize. There are, of course, exceptions to this generally predictable pattern of occurrence, but any bird seen outside the expected period should be studied carefully to make sure it is not a similar species more likely at that season. In some years, certain species may arrive or depart significantly earlier or later than the norm, but such instances are rare.
Because migrants appear in "waves" according to changing regional weather patterns, a species that may, on average, be a "fairly common migrant" could be absent or, alternatively, very common for several days at a time. Typically, birds do not become common until several weeks after the arrival of the first individuals. Likewise, numbers become greatly reduced before the last individuals depart. At the same time, stragglers occasionally may be seen as much as a week or more after the normal departure date or a week or so before the typical arrival date.
In the Tropics, terms such as "winter" and "summer" are not as meaningful as in temperate areas. Some species breed in the Arctic and spend the "winter" in Belize, although they may arrive as early as July and not leave until late May. Likewise, several "summer" species that leave Belize in the winter for South America may arrive as early as February. One "summer" resident, the Gray-breasted Martin, sometimes appears as early as the last week of December! Some observers refer to these species as dry-season residents rather than summer residents, but even that term is less than accurate, because, without exception, species in Belize that appear near the beginning of the dry season do not depart until two to four months after the heavy rains begin in June.
The words "common," "fairly common," and "uncommon" reflect a matter of degree. They are subjective terms. Where does one draw the line between something that is fairly common and something that is uncommon? Where in this continuum, for example, would you place a bird that you might see on average once in every five trips afield? Although these terms are very general, they do serve a useful purpose if properly defined and used only according to each one's definition. As used in this book, these terms are defined below.
For a resident species in appropriate habitat within its normal range:
- Very common (VC): Present in large numbers; seen on every trip afield (Great-tailed Grackle in any urban area)
- Common (C): Seen in small to moderate numbers on nearly every trip afield (Red-throated Ant-Tanager in most woodland habitats; Common Tody-Flycatcher in open areas with trees)
- Uncommon (UC): Seen periodically; not expected on every trip afield (White Hawk in rainforest and forest edge)
- Very uncommon (VU): Seen only once or twice a year (Uniform Crake)
- Rare (R): Seldom seen; distribution spotty, even within seemingly appropriate habitat (Harpy Eagle in mature rainforest)
For transients, these terms are applied somewhat differently, and one additional term is used:
- Very common (VC): Seen frequently in moderate to large numbers but may be scarce or absent on any given day, even during normal periods of migration (Eastern Kingbird in September along the coast)
- Common (C): Seen frequently in small to moderate numbers but occasionally scarce or absent (Red-eyed Vireo in April and October)
- Uncommon (UC): not seen on most days; rarely present in large numbers (Goldenwinged Warbler in April and September)
- Occasional (occas.): Occurs on an infrequent basis; may be missed during an entire period of migration (Canada Warbler)
For species with three or fewer records, each occurrence is given in the text. These species are often referred to as "vagrants" or "accidentals."
The reference section lists articles, books, and audiocassettes and CDs that may be of interest to the reader. Material consulted in developing the species accounts is also listed here. Major works such as Russell (1964), Howell and Webb (1995), and other books with broad coverage of birds in Belize generally are not cited in the species accounts.
One cannot approach the subject of bird identification without referring to specific external parts of a bird. The parts usually refer to feather groups, feather tracts, or soft parts (bill, eyes, legs, and feet). The parts of a bird that are mentioned in the text are shown in the illustrations below. Learning these terms will help considerably in the identification process.