Milwaukee Public Museum

by Nathan Kraukunas

EDITOR'S NOTE: This article is reprinted from LORE magazine (vol 38, no. 4, (Winter, 1988), p. 18-24), a benefit of museum membership. ©1996 Milwaukee Public Museum, Inc.

Milwaukee received a gift from the Milwaukee Public Museum, a new biology hall in the form of a walk-through rain forest. Within this 12,000 square foot gallery, over 135 birds representing over 45 species.

The birds of the American tropics are beautiful, interesting and numerous. In the rain forest of Costa Rica there are 827 species of birds, compared to Wisconsin's 308 species, many of which migrate to the tropics during our long cold winter.

The following are just a few of the birds in the biology hall and a little about their life history.

Resplendent Quetzal

The Resplendent Quetzal (Pharomachrus mocinno) is one of the most beautiful birds in Central America. There are two subspecies which range from southern Mexico to western Panama. both subspecies are mainly found in the higher elevations, up to 3000 meters(9800 feet), of the "cloud" rain forest.

The quetzal is approximately 14 inches in body length, about the size of a pigeon. Both sexes are primarily an iridescent emerald green, which camouflages them in the green of the forest canopy. Males sport a head crest, red breast feathers and may have tail coverts well over three feet long, while females are duller, have fewer red breast feathers and short tailplumes.

The name quetzal comes from an ancient Mexican word for the tail feather, which also means,"precious" or "beautiful." One of the major gods of the Toltec-Maya peoples was Quetzalcoatl, who is depicted wearing the long tail plumes of the male quetzal. The Aztec of Mexico restricted the use of the tail plumes to royalty and nobility. The plumes used in elaborate headdresses came from male quetzals that were caught live, had their tail feathers removed and then were released to grow new feathers.

Quetzals are usually very quiet and shy. During courtship they are much more active with males flying skyward in ling spiral flights trying to impress and attract females. Males will also chase females through the trees of the cloud forest. The breeding season is between March and June. Nests are usually located in old woodpecker or toucan holes. Because they do not have strong beaks and claws, they must find holes in trees with soft rotting wood. They may enlarge these holes for their use. Two eggs are usually laid and both parents share in raising the young. Fruit is the main part of their diet, but they also eat insects, frogs, and lizards.

The Resplendent Quetzal, a species once revered by the Aztec, is now endangered throughout most of its range. Habitat destruction for cattle pasture, stash and burn agriculture and logging of rain forest trees is destroying large tracts of the cloud rain forest which is the birds' prime nesting area. They also fall prey to local people who hunt them illegally to trade and sell their skins and feathers.

The specimen of the Resplendent Quetzal in the Diversity Section of our new exhibit is actually a carved wooden model created by Craig Yanek, an award winning artist in the museum's exhibit and graphics section. The museum's bird collection contains several skins and mounts of quetzals, but all are very old and not suitable for display. Because of Craig's talent, few museum visitors will distinguish this model from a real specimen.

Montezuma Oropendolas

The Montezuma Oropendola (Gymnostinops montezuma) is a member of the blackbird family which includes orioles, blackbirds, caciqies, meadowlarks, cowbirds, and grackles. Oropendolsa range from southern Mexico to Ecuador and Brazil with the Montezuma found from southern Mexico to central Panama.

The male Montezuma Oropendula is about 19 inches in length similar in size to a crow. Females are smaller in length and weight. Both sexes are similar in coloration in that they have a chestnut colored body, a black head and bright yellow outer tail feathers.

Oropendolas nest in colonies ranging in size from four to over one hundred nests, although there are usually between thirty and forty. The large baglike nests, well over three feet in length, are most often found at the edge or in a clearing of the rain forest. Females almost always out number males in colonies, sometimes as high a ration as 5 to 1. Males court the females with unusual displays of bows, wing flapping and strange gurgle-like calls; they will mate with as many females as possible. The breeding season takes place during the dry season, from the end of December to the middle of June. Females weave the large nests and they alone incubate the eggs and feed and care for the young. They may raise up to three broods during the season. Usually two eggs are laid, but the average number of chicks fledged is less than one half percent. The mortality rate is very high in oropendola colonies due to predation by toucans, snakes, monkeys and botfly larvae. The botfly lays its eggs directly on the young birds and if too many larvae hatch, they will kill the bird.

Not all colonies of oropendolas are subject to botfly infestations. Those birds that build their nests in association with wasps or stingless (but biting) bees are protected by these aggressive insects which attack the botflies. Oropendola young also have a higher rate of survival if the Giant Cowbird, a species of bird that does not build its own nests but lays its eggs in the nest of another species, parasitizes the oropendola nest. The cowbird young hatches earlier than the oropendola and eats the eggs and larvae of the botflies, enabling the young oropendola to survive to adolescence.

Oropendolas feed on fruit throughout the year. These fascinating birds may be seen and heard in the new biology hall. Greg Septon of the taxidermy section collected both the birds and nests in Costa Rica for the exhibit.

Scarlet Macaw

The Scarlet Macaw (Ara macao) may be found from southern Mexico to central Panama and from northern South America to central Brazil (east of the Andes mountains) and on the island of Trinidad.

This large macaw is over 33 inches in length and is mainly a bright scarlet red. Its lower back, rump and upper tail coverts are blue and the wing coverts are blue and the wing coverts are yellow with green tips. Its face is almost entirely bare of feathers and creamy-white in color with only small lines of tiny feathers crossing it.

The Scarlet Macaw is probably the best known of all South American parrots. In the wild they are becoming less noticeable because of hunting, trapping and the destruction of rain forest habitat for cattle ranching and agriculture. Wild macaws are most often viewed in pairs, family groups, or in small flocks of up to thirty. As with the other species of macaws there is a strong pair bond evident in most flocks as they fly overhead. The paired birds may fly so close together that sometimes their wings touch.

They take daily flights form their roosting sites to feeding grounds, returning in the evening. Macaws are wary birds and feed on seeds, nuts, berries and leaves. Many of the fruits they eat are raw and unripe and sometimes contain very high amounts of toxins which can be poisonous to other species. Macaws are unusual in that they can eat these highly toxic foods and survive. One theory is that they ingest large amounts of mineral-rich clays which aides their system in detoxifying or neutralizing the poisons.

Nesting occurs in tree hollows and takes place from early January until April. Eggs are elliptical and only two are usually laid. The reproductive rate of wild macaws is very low, of the two young hatched frequently only one survives to be fledged and adults may not nest every year. Little is known of the complete nesting and reproductive cycles of macaws; much more intensive study must be done on this rain forest bird.

The Scarlet and Green-winged Macaws found on the rock structure of the waterfall in the new biology hall are reproductions created by Craig Yanek. An original macaw model was carved in wood, the head was cut off and the body, head and 12 tail feathers were cast in silicone to produce a model. From this model nineteen heads and bodies and 212 tail feathers were produced in urethane plastic which picked out the details of the carved feathers. They were then reassembled in various positions and painted. This process took Craig about a year to do.

Cattle Egret

The Cattle Egret (Bubulcus ibis) is not native to South or North America. It arrived in South America from Africa in 1877 on its own, by flying across the Atlantic Ocean and has spread into North America reaching Wisconsin in the early 1960s. The first nesting record for Wisconsin in 1971. It is now a fairly common bird in the American tropics especially where cattle are raised.

This small white egret stands at about 19 inches. Males and females are identical in coloration, even during the breeding season, when they develop orange-buffy patches on their crowns, back and breast. Their legs and feet are black and they have a yellow-orange bill.

Cattle Egrets may nest in multi-species colonies with herons,ibises and other birds. They nest near water, starting during the rainy season and well into the dry season. A male defends a branch area, as its territory, and after attracting a female,helps in building the nest. The number of light blue eggs laid varies from two to six, depending on available food supply. When the young hatch, they may be as much as two days apart in age and size. The youngest birds may often die, due to older siblings' aggressiveness in getting food from the parents. Both adults care for the young, which leave the nest when they are about 60 days old.

Cattle Egrets usually feed on the ground, very often among cattle. In Africa, they are most often seen feeding among the large herds of elephants, zebra and wildebeest. Their diet in the Americas consist of grasshoppers, spiders, frogs, fish and small birds.

The Cattle Egrets in the new biology hall may be seen in the mural painting of a tropical river,behind the caiman and anaconda struggle. The painting is by Robert Frankowiak, the head of the exhibits and graphics section.

Keel-Billed Toucan

The Keel-billed Toucan (Ramphastos sulfurates), a bird related to the woodpecker, is found from southern Mexico into Venezuela and Colombia. In Costa Rica, it may be found mainly in the wet rain forests of the Caribbean side. Male keel-bills are slightly larger in size and weight than females, averaging about 18 inches in length or twice the size of a robin. The coloration of both sexes is alike--both have a black body, bright yellow bib and cheeks, a white rump, brilliant red undertail coverts and a large banana- shaped brightly colored bill of green,yellow, red, blue and brown.

Both sexes care for the young, which are raised in tree cavities. They may raise as many as two or three broods per year. The diet of keel-bills consists mainly of fruit. They are the largest avian frugivores (fruit-eaters) in the rain forest. Many of the fruit seeds eaten are passed unharmed through the toucan and regurgitated after eating, making toucans a very important species in the tropics for the dispersal of trees and other plants. Besides fruits, they also feed on insects, bird eggs, young bird nestlings, frogs and lizards.

The most distinguished feature of the toucan is its enormous bill. This is a specialized structure which may be several times longer than the toucan's head. It is porous and very light weight, but with strong fiber-like reinforcements within it. This unusual bill is used mainly for feeding, but also may be used for courting and simple sparring with other males for females.

Many Keel-billed Toucans may be found in the biology hall. Some are reproductions produced by Craig Yanek using the same method as he used to produce the macaws, while others are specimens collected and mounted by Greg Septon.

Black Vultures

The Black Vulture (Coragyps atratus) is common over most of central and southern United States to southern South America. They are between 23 and 27 inches in length and have a wing spread of 54 to 60 inches. Sexes are similar in appearance,sporting dark black bodies, with a featherless head and neck or grayish-black skin. White patches at the base of the primary light feathers are seen only while flying. These vultures are smaller in size compared to Turkey Vultures, the familiar Buzzard of western movies. Turkey Vultures may also be found nesting in Wisconsin's southern Kettle Moraine. Black Vultures soar in tight patterns,flap their wings more and hold their wings in a more horizontal position than Turkey Vultures.

Black Vultures are much more aggressive than Turkey Vultures and will drive them away from a food source. They eat mainly carrion and will congregate in cities, dumps and along roads at traffic-killed animals. They seek food by sight. Besides carrion, they will also kill the young of herons, domestic fowl, skunks, opossums, new-born calves, lambs, young turtles and ripe and rotten fruit.

Black Vultures lay their eggs in hollows of trees, on stumps, in caves and even in crannies of tall city buildings in the American tropics. From 1 to 3 eggs are laid. Both parents incubate the eggs for 32 to 39 days, and the young leave the nest about 70 days after hatching. Black Vultures are usually silent, but will hiss, grunt and utter a low barking sound when fighting over food. They are very beneficial birds, in that they consume large amount of garbage, especially from tropical city streets and dumps and animals carcasses from roadsides and pastures.

The three Black Vultures in the biology hall may be seen near and on the tropical research field station. They were collected in Costa Rica and mounted by Greg Septon.

I have only briefly described six species of birds of the American tropics. The rain forest contains numerous species of birds, mammals, reptiles, amphibians and fish all of which make up only a tiny fraction of the total number of species--there are hundreds of thousands, if not millions of species of plants, insects and other invertebrate far out numbering all vertebrate species. New species of animals and plants are discovered and named every year, but because of the daily destruction of large tracts of the rain forest many species will die out without humans ever having known them and discovering how they fit into the overall world ecosystem.