Todies

(Todidae)

Class Aves

Order Coraciiformes

Suborder Alcedines

Family Todidae

Thumbnail description
Very small, rather plump kingfisher-like birds with long, somewhat flattened red bills, crimson gorget, stubby tail, shining green wings, and dorsal plumage

Size
4.0–4.6 in (10–11.5 cm); 0.19–0.27 oz (5.2–7.5 g)

Number of genera, species
1 genus; 5 species

Habitat
Tropical forests and woodlands, primary and secondary, ranging from arid lowlands to lushly forested highlands

Conservation status
Not threatened; locally common, although in 2001 population densities decreasing due to habitat destruction.

Distribution
Greater Antilles, West Indies

Evolution and systematics

Five species comprise one of the most uniform families in the ornithological world. Early taxonomists, analyzing museum skins tagged with exceedingly sparse field notes and puzzling over their relationships, allied them in a mixed bag: nightjars, trogons, jacamars, puffbirds, barbets, motmots, kingfishers, broadbills, cotingas, manakins, flowerpeckers, and tyrant-flycatchers. Until about 1900, all were regarded as variations of the Jamaican tody (Todus todus), then Todus viridis. Ultimately, these endearing Caribbean birds entered the order Coraciiformes, reflecting close kinships with motmots and kingfishers.

Fossils are unfortunately extremely scant: ancestral fossils (Palaeotodus emryi), are known from the Oligocene of Wyoming (37–24 million years ago), France, and Switzerland. Palaeotodus, although fragmentary, suggests close affinities with today's tody motmot (Hylomanes momotula) and the Swiss fossil Protornis glarniensis, a missing link between contemporary todies and motmots.

Geographical, paleontological, behavioral, morphological, and genetic data aid in the construction of a hypothetical evolutionary scenario for tody evolution. Approximately 30 million years ago, a primitive motmot/tody-like ancestor inhabited Northern Hemisphere forests. Twenty million years ago, climates began cooling, and by seven million years ago, only relict (from an earlier geological period) tody-motmot populations survived. Eventually, Central American birds similar to today's todies flew eastward, colonizing large Caribbean islands and evolving into five species. This was possible because of Ice Age glaciations (one million years ago), when polar icecaps froze gigantic volumes of sea water, lowering sea levels worldwide by about 300 ft (90 m), thus reducing distances between continents and islands.

Physical characteristics

Todies are tiny, plump-bodied, large-headed, stub-tailed birds that characteristically perch with bill uptilted. Shining emerald-green above and creamy below, with a prominent crimson bib and a long, flat, bicolored red-and-black bill, each bird bears some resemblance to a miniature kingfisher or hummingbird. Visible similarities are accented by behaviors such as hovering and zooming courtship displays. Todies resemble kingfishers so much that taxonomist Linnaeus mistakenly applied a kingfisher genus (Alcedo) to the first tody described—the Jamaican. Conversely, locals in Hispaniola call todies colibri, which means hummingbird in Spanish.

Individual species are distinguished by flank and belly color (pink and yellow, yellow, greenish yellow), by cheeks (sky blue, gray), and by unique vocalizations. A family trademark, the scarlet bib, elicited curiosity from earliest times. For example: "As it sits on a twig in the verdure of spring, its grass-green coat is sometimes indistinguishable from the leaves in which it is embowered, itself looking like a leaf; but a little change in position, bringing its throat into the sun's rays, the light suddenly gleams as from a glowing coal" (Gosse, 1847).

Like most tropical forest birds, adult todies show no obvious seasonal differences in plumage. However, the dull attire of a summer adult, frazzled from raising three or four ravenous nestlings, can hardly compare with its shiny, semi-iridescent, feathered attire of early spring.

Flat, narrow, and shallow, the bill is ideally shaped for feeding—snapping up insects from the undersides of leaves in short, sweeping forays. Todies' short, rounded wings and loosely fluffed plumage are perfectly designed for their short flight paths and non-migratory lifestyles. Species flying the greatest distances on feeding forays have the longest wings.

Distribution

The family's geographical distribution is restricted to the Greater Antilles, West Indies. Cuba, Jamaica, and Puerto Rico each have one species, while Hispaniola supports two (narrowbilled tody [Todus angustirostris] and broad-billed tody [Todus subulatus]). The latter species are usually separated by habitat and elevation; where overlap occurs, foraging behavior provides classic insights into ecological isolating mechanisms.

Habitat

Three major factors limit tody distribution: vegetation, insect abundance, and territory requirements—especially the availability of suitable nesting banks. They occupy diverse habitats, ranging from 160 ft (50 m) below sea level to elevations

above 9,800 ft (3,000 m). They favor brush and forest with interlacing foliage, epiphytes, and vines. Specific habitats include lowland or mountain rainforests (very dry to extremely lush, including elfin woodlands), pine groves, second growth, streamside vegetation, pasture borders, limestone karst, cactus deserts, and shaded coffee plantations. These little avian jewels are never garden birds; favoring natural forests, they adapt poorly to human incursion into their domains, except for roadcuts, which are welcomed for nesting.

Behavior

The first glimpses of todies are invariably of diminutive, vivid green, rapidly bobbing birds uttering loud nasal beeps that are quite disproportionate to their size. Adults and children consider them cute, joining the company of old-time naturalists. For example, here is a quote from esteemed ornithologist Dr. Alexander Wetmore: "If there be gnomes and elves in our world of birds, among them are the tiny todies, whose long, spade-like bills, light eyes, brilliant plumage and peculiar mannerisms make them the dwarfs and hobgoblins of the West Indian forests…their acquaintance is one of the greatest pleasures that comes to a foreign ornithologist travelling in their haunts" (1927).

Although strictly territorial, todies temporarily join mixed species feeding flocks passing through their territories. This behavior is pronounced during autumn and spring, when migrating warblers (Parulidae) visit West Indian forests. Here, the avifauna is impoverished compared to that of the continental tropics, so flocks are small, often averaging only six species.

Because todies are among the smallest and most active feeders of all birds, it is only natural that they have evolved effective modes of conserving energy. They do not employ typical methods of keeping warm, such as group roosting and huddling. Instead they rely on internal physiological mechanisms. The Puerto Rican tody, for instance, exhibits a very low normal body temperature of 98.1° F (36.7° C), rather than the 104° F (40° C) typical of its relatives. This enables it to decrease its expected energy expenditure by 33%, reducing the body's demand for additional heat production.

Most birds are homeotherms, just like people. This means they maintain a constant body temperature with little fluctuation. The Puerto Rican tody exhibits a rare thermoregulatory pattern in which its basic temperature varies widely. It can consciously control its normal body temperature by 27° F (15° C) from 82 to 109° F (28–43° C).

True torpor is relatively rare among birds. Todies not only exhibit torpor, but a controlled, sex-dependent, low metabolic rate that saves females approximately 70% of their daily energy expenditure.

Feeding ecology and diet

Voracious tody appetites require super-abundant annual food supplies. For example, for three years, feeding rates of Puerto Rican todies averaged 1.9 insects per minute in arid scrub and 1.1 per minute in rainforest. One of the highest chick feeding rates ever recorded for birds was when 420 feeds per day were delivered to a brood of three tody nestlings.

Fifty insect families have been identified as prey, chiefly grasshoppers, bugs, moths, butterflies, flies, cockroaches, damselflies, mantises, mayflies, and ants. Todies also consume seeds, lizards, and spiders. Fearsome creatures (scorpions, whipscorpions, snakes) are wisely avoided.

Tody feeding behavior resembles that of tody-flycatchers (tropical America). All capture insects using a distinctive aerial feeding technique, the underleaf-sally. With head directed upward, the bird scans undersides of leaves. Alert, jerking head and eyes rapidly, it darts upward at a shallow angle and, winging a short parabolic flight path, snatches an insect and continues in an unbroken arc to another perch. Occasionally, todies also swoop downward to snap insects from leaf surfaces, or hover in mid-air.

Todies prefer low-to-middle forest strata, often at eye level. Broad-billed todies feed higher than narrow-billed todies, a survival tactic that has evolved in the only two tody species whose geographical ranges overlap.

Reproductive biology

Loud courtship displays involve male-female chases and vigorous wing-rattling and wing-cracking. They pursue each other, often at lightning speed, weaving around foliage in parabolic arcs and circles. Another stunning component of courtship is the flank display, best developed in the pink-thighed species. For example, when the Cuban tody's display is at its height, its tiny body inflates into a green, neckless fuzzball with bright rosy flank tufts touching middorsally. Simultaneously, this fluffy avian ball hops and bobs rapidly, uttering loud vocalizations to attract the perfect mate. Once paired, a mutual gift exchange of fresh insects occurs, like a bridal couple feeding each other slices of wedding cake.

The first (and rather quaint) published description of tody nesting habits comes from Moritz of Puerto Rico (1836): "In shady trees is seen once in a while the lovely green San Pedrito, rattling hoarsely…The locals believe that it nests in holes in the earth." It is true; todies are burrow-nesters, like their kingfisher cousins. They excavate cylindrical, angled tunnels in vertical soil embankments that are typically low, amphitheater-shaped slippages, roadside cuts, or natural inclines. The most successful burrows are those hewn from moderately overgrown embankments providing soil stabilization and partial concealment from predators.

Fresh tunnels are dug annually, primarily February to May. Each requires about eight weeks. Long, strong tody bills act as chisels to gouge out soil, while their tiny feet scrape away underneath. They tunnel energetically, initially visiting up to 60 times per hour.

Tody eggs are exceptional in the avian world in that they are huge compared to the bird's size. Average egg weights are 26% of the adult's body weight, comparable to the well-known case of New Zealand kiwis. For comparison, egg-to-body-weight ratios of most birds range from 1.8–11%. Normally todies lay only one clutch (average 2.4 eggs), but will re-lay if it is destroyed. Eggs are tiny, white, glossy, and ovate.

Known incubation periods are 21–22 days, while nestling periods are 19–20 days. Each parent spends only two to three daylight hours incubating, a stark contrast to the assiduous kingfishers, which incubate up to seven continuous hours daily. Hatching occurs principally in the late afternoon, with one attendant adult in the nest chamber. Nestlings are naked, bearing conspicuous cushioned heels that cover the feet and legs with thick pads of swollen skin and leathery tubercles, like a baby born with leather boots.

Tody parents may not be over-attentive incubators, but once the chicks hatch they become highly diligent, supplying enormous quantities of insects to the offspring.

Notable also is nest-helping. As of 2001, nest assistance by one or two other adults during incubation and nestling periods is only known in the Puerto Rican tody. Two independent studies concluded that at least 50% of breeding pairs were given assistance. Nests with helpers contained significantly larger clutches (2.9 eggs) than did those without (2.3); chicks also grew quicker and fledged earlier than normal. Nest-helping is especially favorable in rainforests, where torrential rain often limits tody foraging rates. Banding studies suggest that helpers are not young from the previous year, and are likely adults from nearby territories whose breeding activities were curtailed or that did not breed at all. Nest cooperation in todies is unique because there is no apparent genetic relationship between helpers and recipients.

Adult todies use many innovations in teaching independence to newly fledged chicks. Weaning is not easy. Parents sometimes force them to fly by pushing them off perches or hovering in front of them with food in the bill, then pulling away at the last moment. Females are more likely to give in to a hungry chick than males. At times males physically prevent females from feeding fledglings. For the first six weeks, young todies have short black bills and gray bibs whose feathers gradually turn crimson. The entire repertoire of adult behavior is not achieved for several months.

Conservation status

As a family, todies seem reasonably secure. Overall, they remain common in natural habitats with high insect abundance. Only the narrow-billed tody is considered Near Threatened. Todies have partly benefited from human activities, excavating burrows in road cuttings and trailside banks. Clear-cutting and urbanization spell doom. They also cannot adapt to gardens, orchards, or pastures.

Little information is available concerning increasing pesticide use. On Cuba's Cayo Coco, currently undergoing rapid tourism expansion, malathion is sprayed aerially in wetlands and forests; hand-held fogging sprayers are also commonly used around hotels to combat mosquitoes. Pesticides decimate tody populations.

Coffee plantations formerly thrived under shady, indigenous trees. Here, todies enjoyed healthy populations and controlled insect numbers. From the 1980s on, international corporations discovered that growing coffee in direct sunlight was more profitable, although the beans were more bitter. Todies cannot adapt to modern coffee plantations, where pesticides are used liberally.

Although natural predators on wildlife are inevitable, introduced predators present greater threats. Todies are no exception; their numbers are everywhere seriously reduced by Indian mongooses (Herpestes auropunctatus), voracious mammals that destroy approximately 80% of tody burrows in Puerto Rico's rainforests. As the world's human population increases exponentially, human predation also increases. Many West Indians are sufficiently poor that they seek supplemental protein, however scant. Because tody nest holes are common along roads and trails, they succumb to such predation.

Significance to humans

Despite their tameness and abundance in varied habitats, todies were never culturally significant beyond their role as an ecotourism draw. Locals bestowed many endearing names on them: their bank-nesting habits prompted the French perroquet de terre (parakeet of the earth), and the Spanish barrancoli, barranco-rio, and barranquero (from la barranca, the Spanish word for bank). Confusion with hummingbirds inspired the Spanish colibri (hummingbird) in Hispaniola. A common vernacular in Puerto Rico is papagayo (loud, noisy), and bird enthusiasts in Jamaica often use robin red-breast.

Species accounts

List of Species

Cuban tody

Todus multicolor

taxonomy

Todus multicolor John Gould, 1837, Cuba.

other common names

French: Todier de Cuba; German: Vielfarbentodi; Spanish: Barrancolí Cubano.

physical characteristics

4.3 in (10.8 cm), wing chord 1.7 in (4.4 cm), estimated weight 0.21–0.23 oz (6–6.5 g). Most brilliantly colored tody, with smallest bill. Rosy flanks, yellow undertail coverts. Sky-blue cheek patch and wrists; yellow base of bill, whitish belly. Yellow-green, almost iridescent eyebrow.

distribution

Cuba, including Isle of Pines (Isle of Youth) and larger cays off Cuba's north coast.

habitat

Ecologically adaptable. Locally common in xeric (extremely dry), moist, and wet forests; mountains; and lowlands, especially in gullies. Only tody inhabiting shoreline vegetation. Highest elevation recorded 8,184 ft (2,494 m) (Sierra Maestra).

behavior

No recorded movements.

feeding ecology and diet

Primarily insectivorous, plus spiders and lizards. Mean foraging height 9 ft (2.6 m) in arid scrub.

reproductive biology

Monogamous with striking courtship, exhibiting bright pink flanks. Smallest eggs in family. Breeds April to June. Excavates burrows in earth banks, rotten logs, natural limestone cavities, and (rarely) cave entrances. On Cayo Coco, uses sand at entrances of crab burrows.

conservation status

Not threatened. In 1970, common in protected Guantanamo Naval Base. Cuba's poverty and unstable economy may affect tody populations. Recent pesticide use has reduced tody populations.

significance to humans

May be eaten in economically depressed areas and, like all todies, a delight to young and old.

Puerto Rican tody

Todus mexicanus

taxonomy

Todus mexicanus Lesson, 1838, Tampico and Vera Cruz, Mexico. Clearly an error: todies do not occur in Mexico.

other common names

French: Todier de Puerto Rico; German: Gelbflankentodi; Spanish: Barrancolí Puertorriqueño.

physical characteristics

4.4 in (11 cm), wing chord 1.7 in (4.3 cm), weight male 0.22 oz (6.3 g), female 0.21 oz (5.9 g). The least colorful, smallest tody. Flanks yellow, no pink, no blue cheek patch, belly whitish. Sexual dimorphism in eye color: slate (males), white (females). Juveniles have four maturation stages (three weeks) when bill lengthens to adult size, grayish bib brightens to crimson, and yellow flanks develop.

distribution

Puerto Rico.

habitat

Rainforests, arid scrub, coffee plantations, moderately wet forests, karst (limestone) topography, often near streams.

behavior

Maintain year-round home ranges and breeding territories. Usually single or paired, never in pure flocks although may temporarily join mixed feeding flocks.

feeding ecology and diet

Typical tody. Insectivorous, 50% of diet is flies and beetles. Also spiders, nematodes, millipedes, lizards, and fruits from six families (principally Ficus, Chenopodium, Rubus, Xanthoxylum, Psychotria, Clusia). Adults select sizes and variety of nestling foods.

reproductive biology

Burrow excavation primarily February to May. Tunnel horizontal, almost always with right-angled curves and enlarged, depressed, unlined terminal chambers. Average burrow length in rainforest 13.9 in (30.5 cm). Nest helping common. Clutch size averages 2-4 eggs.

conservation status

Not threatened. No recent information on status but populations diminishing due to habitat destruction and non-shade coffee.

significance to humans

None known.

Resources

Books

Gosse, P. H. The Birds of Jamaica. London: John Van Voorst, 1847.

Kepler, A. K. Comparative Study of Todies (Todidae), with Emphasis on the Puerto Rican Tody, Todus mexicanus. No. 16. Cambridge, MA: Nuttall Ornithology Club, 1977.

Kepler, A. K. "Family Todidae." In Handbook of the Birds of the World, edited by J. del Hoyo, A. Elliott, and J. Sargatal. Vol. 6, Mousebirds to Hornbills. Barcelona: Lynx Edicions, 2001.

Sibley, C. G., and B. L. Monroe. Distribution and Taxonomy of Birds of the World. New Haven and London: Yale University Press, 1990.

Periodicals

Bond, J. "Origin of the Bird Fauna of the West Indies." Wilson Bulletin 60 (1948): 207–229.

Latta, S. C., and J. M. Wunderle, Jr. "Ecological Relationships of Two Todies in Hispaniola: Effects of Habitat and Flocking." Condor 98 (1996a): 769–779.

Latta, S. C., and J. M. Wunderle. "The Composition and Foraging Ecology of Mixed-species Flocks in Pine Forests of Hispaniola." Condor 98 (1996): 595–607.

Merola-Zwartjes, M., and J.D. Ligon. "The Ecological Energetics of the Puerto Rican Tody: Heterothermy, Torpor, and Intra-island Variation." Ecology (in press)

Olson, S. L. "Oligocene Fossils Bearing on the Origins of the Todidae and Momotidae (Aves: Coraciiformes)." Smithsonian Contributions to Palaeobiology No. 27 (1976): 111–119.

Oniki, Y. "Temperatures of Some Puerto Rican Birds, with Note of Low Temperatures in Todies." Condor 77 (1975): 344.

Ricklefs, R. E., and E. Bermingham. "Molecular Phylogenetics and Conservation of Caribbean Birds." El Pitirre 10, no. 3(1997): 85–92.

Wetmore, A. "Birds of Porto Rico." Bulletin of the U.S.Department of Agriculture. 326 (1916): 1–140.

Wetmore, A. "Birds of Porto Rico and the Virgin Islands. Scientific Survey of Porto Rico and the Virgin Islands." New York Academy of Sciences 9, no. 4 (1927): 245–598.

Wetmore, A., and B. H. Swales. "The Birds of Haiti and the Dominican Republic." Bulletin of the United States National Museum 155 (1931): 1–483.

Wunderle, J. M., and S. C. Latta. "Avian Abundance in Sun and Shade Coffee Plantations and Remnant Pine Forest in the Cordillera Central, Dominican Republic." Ornitologica Neotropical 7 (1996): 19–24.

Angela Kay Kepler, PhD