Tanagers in Captivity by Anne Oiler, Tanagers Are Beautiful, Colorful Lead Keeper, Brookfield Zoo Bird Dept
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The Biology and Husbandry of Tanagers in Captivity by Anne Oiler, Tanagers are beautiful, colorful Lead Keeper, Brookfield Zoo Bird Dept. Housing and Environment birds that are not well known either in At Brookfield Zoo, tanagers are Patty McGill, Ph.D., exhihited in several different sized the wild or in captivity. Taxonomically, Curator of Birds, Brookfield Zoo the 242 species of tanagers, honey enclosures, ranging from small "pic ture-window" exhibits to the large creepers, dacnis, and others, compris Scott Schiller, ing approximately 58 genera, are Senior Keeper, Brookfield Zoo free-flight aviary. In 1982, an off-exhih placed in the subfamily Thraupinae of The Swamp it facility, the "Avian Propagation the large family Emberizidae Environment" (APE), was huilt. (buntings, sparrows, and finches). Approximately one-fifth of the Tanagers have successfully hred in the They are distributed primarily through Thraupinae (49 species) reside in only APE, the free-flight aviaI)', in a douhle out tropical Central and South one country. How those countries picture-window enclosure, and in America. Generally small-bodied and approach conservation and develop "walk-ins" (a larger version of picture quite vocal, tanagers inhabit forests or ment will determine the long-term windows). Each of the exhibit types shrubby habitats, ranging from low prospects for these species. offers the hirds a slightly different envi land to montane. They are truly the According to the 1994 ISIS ronment and each has both advan jewels of the canopy, often living in (International Species Inventory tages and disadvantages. mixed-species flocks of various-col System), of the 11 genera of tanagers ored birds. Some species are sexually that have species listed in the Red List Free-flight Aviary dimorphic, whereas in many the males Book, three have at least one species in Advantages: The aviary is heavily and females appear the same. They captivity. None of the listed species planted with a variety of tropical exhibit variation in bill shape and leg themselves are in captivity and only plants, including a large weeping ficus musculature associated with their dif one of those three genera has been Ficus benjimina and Zulu fig tree ferent feeding habits - insectivorous, successfully bred in captivity over the Ficus macrophylla. A shallow stream, frugivorous, or nectivorous. past five years. There may be addition including a small waterfall and four The status of birds in the wild can al birds or breeding success in non-ISIS pools of various depths, runs through be evaluated by an overview of rare, groups, particularly in private collec the middle of the exhibit. The stream threatened, or endangered species. tions, hut we have no way to quantify proVides water for hirds to drink and Three species of tanagers and their this. Thus, based on the current status bathe. The pools allow small water allies were included in these categories of tanagers in captivity, the prospect of fowl to swim. in the International Council for Bird using captive propagation to holster The public can only access the first Preservation's (lCBP) 1997 Red List threatened populations is low. 10 X 30 feet of the exhibit space. Book. That number has since changed. With many declining populations in Humidity varies with ambient con The latest list of threatened bird the wild and increased legislation and ditions. A fogging system was installed species, found in the Birds To Watch 2 requirements for permits in both the in 1992 to reduce high summer tem (Collar et al. 1994), now includes 20 countries of origin and the United peratures and provide winter humidi species of tanagers from 13 genera. States, it is no longer responsible nor ty. Using either preset humidity/tem Species at risk often have restricted dis easy to take these birds from the wild. perature settings or manual controls, a tribution or use very limited habitats; This group of birds is in need of dedi cloud is dispersed in the upper levels 30 genera within this group show cated efforts to develop and sustain of the exhibit through fine nozzles. these patterns. It is likely then that long-term breeding success. Many birds enjoy bathing in this mist. additional species may be added to the Brookfield Zoo's tanager breeding lists of threatened birds. program has been one of the most Disadvantages: The spacious Other realities of modem conserva consistently successful among zoos in aviary, with its live plants and trees, tion are the sometimes extreme differ North America. Over the past 18 years, allow the birds to distance themselves ences in philosophy, conservation captive propagation of nine species of from the viewing public in a simulated ethic, and economic resources tanagers, one euphonia, and one hon forest canopy. However, the size and between countries. Therefore, another eycreeper has been attained. The height of the exhibit can be dangerous factor potentially affecting survival of information in this article comes from for fledglings. It is difficult to provide species is whether they are found in our own experience and research as artificial nest cups at high levels, or to only one country, or whether their dis well as from discussions with many remove injured or sick birds from the tribution crosses political boundaries. colleagues. exhibit. 8 January/February 2000 nesting material are uncomplicated, The Avian Propagation Walk-ins and Picture Windows and landings of fledglings are much Environment (APE) Advantages: The walk-ins and pic safer. Advantages: The APE is comprised ture windows vary in size but general of 25 cages of various widths, from ly are quite similar. Both have at least Disadvantages: The small size of three to eight feet, but all are eight feet one glass wall for public viewing and the picture-window exhibits coupled in height. Originally, the cages were skylights to provide natural light. The with the large glass front hinders some woodframed, but aluminum frames birds in the picture windows and breeding pairs. Unfortunately, the light were installed in all cages in 1993. The walk-ins are more visible. Observations level is not sufficient for most live cement floor is easily disinfected. An of the behaviors of the breeding pairs, plants to thrive. These enclosures are overhead misting system, operated their food consumption and choice of mainly used for exhibit purposes only. manually, can increase humidity and simulate rain. The entire roof is sky TABLE 1 lights. Characteristics of Tanagers Housing at Brookfield Zoo Skylights provide natural light but conduct heat in the summer; they also PICTURE- FREE provide a natural photo period. HOUSING WINDOW WALK-IN FLIGHT OFF-EXHIBIT Variable timers regulate the fluorescent EVALUATION EXHIBITS EXHIBITS AVIARY FACILITY lights and can be adjusted to vary the daylength. In the APE, the daylength is S'W 9.S'W 13.S'W S2'W 3-IO'W supplemented by artificial lights on S'O 4.S'O 7'W 32'0 7'0 timers for 10-13.5 hours of light, simu DIMENSIONS S'H S'll S'H 30'H S'H lating daylength at 20° latitude. The Skylights and Skylights and Skylights and Skylights and APE has minimal disturbance from LIGHT fluorescent fluorescent bulbs quartz flood fluorescent bulbs people and the environment is strictly SOURCE bulbs lights controlled. Limited live Limited live Variety of Live plants, plants; plastic plants; plastic and live plants mostly ficus Disadvantages: The cages' low VEGETATION and silk plants silk plants ceilings and the birds' lack of privacy Sand Sand Soil base Cement floor from neighbors may hinder breeding with leaf in some species. It is also difficult to SUBSTRATE litter observe pairs without disrupting other Overhead individuals. As a less intrusive tech Mist with hose Mist with hose tri- misting (fog) nique, we now use video cameras to HUMIDITY tri-weekly weekly system monitor the birds, either taping for later review or viewing via live remote. TABLE 2 Social Conditions Summary of Nesting Preferences of Tanager Species at Brookfield Zoo (Greer 1988) Most small, omnivorous tanagers, forest euphonias, and dacnis are often TANAGER NATURAL ARTIFICIAL NEST NEST SPECIES NEST NEST NESTING MATERIALS LOCATION HEIGIIT(rq found in flocks that seem to form and covered basket. yarn. moss, hair. burlap various 6+ disband irregularly at certain times of BLUE-GRAY open cup planter the year. This varies greatly by species BLUE· AND· YELLOW open cup - twigs. grass. plant fibers ficus tree 10-15 CIsler 1987). Canopy-dwelling multi yun. moss, hair. burlap under plant 6% FLAME-FACED - hanging planter leaves species flocks have been studied and covered basket, moss, plant fibers, le.aves ficus tree 5-6 shown to contain as many as 16 GOLDEN -- planter species 'of tanagers (Robinson 1988). hardware cloth small tMgs, hair, ficus leaves various 6·7 GREEN-AND-GOLD open cup basket Brookfield Zoo has housed mixed hardware eloth moss, ficus leaves, stripped buk bung from uiling 7 flocks of· tanagers in both the aviary PARADISE - basket and the walk-ins. In the aviary, the open & covered moss, cotton. buk and fibert in dem;e tree 5·25+ TURQUOISE open cup basket foliage flock composition varies from year to ficu!II tree - covered basket moss 5 year, but normally encompasses GOLDEN-EARED approximately 20-40 birds. To prevent open cup open cup twigs, grass. leaves ficus & palm tnoe 4-20 RED-rnROATEDANT interspecific competition, these flocks ORANGE· BELLIED - covm:d buket bemp. raffia IT«: 4 EUPHONIA are limited to single pairs of each THlCK·BILLED covered basket