The Biology and Husbandry of Tanagers in Captivity

Abstract

Tanagers are beautiful, colorful birds that are not well known either in the wild or in captivity. Taxonomically, the 242 species of tanagers, honeycreepers, dacnis, and others, comprising approximately 58 genera, are placed in the subfamily Thraupinae of the large family Emberizidae (buntings, sparrows, and finches). They are distributed primarily throughout tropical Central and South America. Generally small-bodied and quite vocal, tanagers inhabit forests or shrubby habitats, ranging from lowland to montane. They are truly the jewels of the canopy, often living in mixed-species flocks of various-colored birds. Some species are sexually dimorphic, whereas in many the males and females appear the same. They exhibit variation in bill shape and leg musculature associated with their different feeding habits - insectivorous, frugivorous, or nectivorous.

The status of birds in the wild can be evaluated by an overview of rare, threatened, or endangered species. Three species of tanagers and their allies were included in these categories in the International Council for Bird Preservation's (ICBP) 1997 Red List Book. That number has since changed. The latest list of threatened bird species, found in the Birds To Watch 2 (Collar et al. 1994), now includes 20 species of tanagers from 13 genera. Species at risk often have restricted distribution or use very limited habitats; 30 genera within this group show these patterns. It is likely then that additional species may be added to the lists of threatened birds.

Other realities of modem conservation are the sometimes extreme differences in philosophy, conservation ethic, and economic resources between countries. Therefore, another factor potentially affecting survival of species is whether they are found in only one country, or whether their distribution crosses political boundaries.

Approximately one-fifth of the Thraupinae ( 49 species) reside in only one country. How those countries approach conservation and development will determine the long-term prospects for these species.

According to the 1994 ISIS (International Species Inventory System), of the 11 genera of tanagers that have species listed in the Red List Book, three have at least one species in captivity. None of the listed species themselves are in captivity and only one of those three genera has been successfully bred in captivity over the past five years. There may be additional birds or breeding success in non-ISIS groups, particularly in private collections, hut we have no way to quantify this. Thus, based on the current status of tanagers in captivity, the prospect of using captive propagation to holster threatened populations is low.

With many declining populations in the wild and increased legislation and requirements for permits in both the countries of origin and the United States, it is no longer responsible nor easy to take these birds from the wild. This group of birds is in need of dedicated efforts to develop and sustain long-term breeding success.

Brookfield Zoo's tanager breeding program has been one of the most consistently successful among zoos in North America. Over the past 18 years, captive propagation of nine species of tanagers, one euphonia, and one honeycreeper has been attained. The information in this article comes from our own experience and research as well as from discussions with many colleagues.

Housing and Environment

At Brookfield Zoo, tanagers are exhibited in several different sized enclosures, ranging from small "picture-window" exhibits to the large free-flight aviary. In 1982, an off-exhibit facility, the "Avian Propagation Environment" (APE), was built. Tanagers have successfully bred in the APE, the free-flight aviary, in a double picture-window enclosure, and in "walk-ins" (a larger version of picture windows). Each of the exhibit types offers the birds a slightly different environment and each has both advantages and disadvantages.

Pree-flight Aviary

Advantages: The aviary is heavily planted with a variety of tropical plants, including a large weeping ficus Ficus benjimina and Zulu fig tree Ficus macrophylla. A shallow stream, including a small waterfall and four pools of various depths, runs through the middle of the exhibit. The stream provides water for birds to drink and bathe. The pools allow small waterfowl to swim.

The public can only access the first 10 X 30 feet of the exhibit space.

Humidity varies with ambient conditions. A fogging system was installed in 1992 to reduce high summer temperatures and provide winter humidity. Using either preset humidity/temperature settings or manual controls, a cloud is dispersed in the upper levels of the exhibit through fine nozzles. Many birds enjoy bathing in this mist.

Disadvantages: The spacious aviary, with its live plants and trees, allow the birds to distance themselves from the viewing public in a simulated forest canopy. However, the size and height of the exhibit can be dangerous for fledglings. It is difficult to provide artificial riest cups at high levels, or to remove injured or sick birds from the exhibit.