Field Studies of African Grey Parrots

in the Central African Republic

 

Diana L. May

Department of Psychology, Psychobiology Program

University of Arizona

Tucson, Arizona 85721

USA


Excerpted from the Proceedings of the International Aviculturists Society, January 1996, Orlando, FL

 

Introduction And Background

Worldwide, the African Grey Parrot is the third most commonly traded wild bird species (RSPB 1991 cited in Dändliker 1992) and is perhaps the most popular Psittacid imported into the United States (Dr. Rosmarie Gnam, pers. comm.). This popularity may be attributed to the African Grey Parrot's intelligence and extraordinary mimetic abilities. Ironically, however, little is known about the behavior of African Grey Parrots in the wild (Chapman, Chapman & Wrangham, unpub. ms. 1991, see however, Dändliker 1992; Cruickshank, Gautier & Chappuis 1993). Two reasons we might want to know more is (1) to understand how the cognitive capabilities that we have examined in the laboratory (see Pepperberg 1987, 1990, 1994a-b) are actually used in the African Grey Parrot's natural world, and (2) to develop strategies that will preserve wild populations and their habitats.

If the behavior of birds, rather than their environment, drives their evolutionary change (Gill 1990), perhaps the most significant African Grey Parrot adaptations are their cognitive, communicative, and mimetic abilities, especially those abilities that function in social behavior. Laboratory research has examined African Grey Parrot cognitive and communicative capacities through tasks including discrimination problems (Koehler 1972; Lögler 1959, Braun 1952), tool-use (Boswall 1977; Janzen, Janzen & Pond 1976), and tests of numerical competency (Koehler 1950, Lögler 1959), some of which include vocal labeling of quantities up to six (Pepperberg 1987, 1994a). Pepperberg's 18-year-study of a captive African Grey Parrot shows that this bird vocally requests objects and correctly replies to queries about object identity, color, shape, relative size, same/different, quantity and absence, and also to queries involving various combinations of these dimensions (Pepperberg 1990, 1994a-b). These skills apparently develop best by learning in a social context (Todt 1975, Pepperberg 1994b).

Although such laboratory research has provided a wealth of evidence for captive African Grey Parrot capabilities, limited field research has provided only a hint of African Grey Parrot abilities and their use in wild populations. Cruickshank et al. (1993) provided the first published evidence of vocal mimicry by wild African Grey Parrots in their natural habitat. Their analysis of African Grey Parrot recordings in Zaire shows mimicry of nine species of birds and a bat, but these results provide no explanation or rationale for this behavior. No other recent studies have specifically addressed African Grey Parrot behavior in the wild (see however, general descriptions of behavior by Dändliker 1992). I am now in the process of examining the behavior in detail by developing an ethogram (Martin & Bateson 1986). The results will provide both a solid description of African Grey Parrot behavior as it occurs in the wild and a basis for future studies of cognitive capacities.

Another reason for studying African Grey Parrot behavior is to conserve the species. The principal threat to the African Grey Parrot is trade; therefore, ecotourism (Munn 1992, 1994 and 1995) and sustainable harvest (Beissinger & Bucher 1992) seem sensible and cost-effective conservation strategies that, if implemented, will ensure viable future populations of African Grey Parrots. Both of these strategies, however, require sufficient biological data (Dändliker 1992, note Snyder, James & Beissinger 1992). The ethogram that I am currently developing will show both how African Grey Parrots interact with their environment and how human observers affect African Grey Parrot behavior. In this way, my study will help to assess the feasibility of ecotourism and sustainable harvest as conservation alternatives to the current practice of intensive harvest for the pet trade.

 

Project Description

Goals

My study has two short-term goals: to assess the feasibility of a long-term field study of African Grey Parrot behavior and to collect preliminary information necessary for the design and implementation of ecotourism as a conservation strategy for African Grey Parrots.

To achieve the first short-term goal, I am constructing an ethogram using videotapes of African Grey Parrot behavior; the ethogram will allow me to judge the feasibility of its use for long-term study in three ways. First, I will identify the amount and types of behavioral data that were collected. Second, I will create definitions of and guidelines for assigning behavioral elements that will provide the ethogram's underlying structure. Third, when the underlying structure is complete, I will test the ethogram's utility and inter-observer reliability.

Achieving the second short-term goal will require some understanding of the natural history of African Grey Parrots. Knowledge of daily activities (e.g., where and when the parrots forage for food) and possible effects of human presence on African Grey Parrot behavior are important for the design and implementation of conservation practices. During my study, I collected some of this information in the form of written field notes and videotape; further anaylsis for the ethogram will provide even more information.

My long-term goal is to examine the functional role of specific African Grey Parrot signals. These signals may be important to flocking, foraging, reproduction, and predator avoidance (Seyfarth & Cheney 1980, 1990, Macedonia & Evans 1993). If signals are critical to African Grey Parrot survival, then the only way to understand the importance of these signals is to study them in detail.

As a first step toward achieving the long-term goal, I recorded general observations of group and individual behavior, made video recordings of all visually observable behavior to develop an ethogram and made audio recordings of vocalizations for eventual use in playback experiments on African Grey Parrot acoustic signals. Notes based on general observations provide context information to supplement video footage. An ethogram will provide a systematic behavioral inventory of African Grey Parrot behavior that shows species-typical behavior. Audio recordings of African Grey Parrot signals will provide the raw materials for future playback experiments. The combined use of video and audio recordings will help me to identify some of the vocalizations that have salient effects on the behavior of the parrots. These vocalizations can then be edited for future playback experiments with use of the OCEAN computer program and a Kay sonagraph. Playback experiments, using edited recordings, will show correlations between specific acoustic signals and their effects in various situations. From these correlations, I will be able to make potential inferences about each signal's function and possibly identify the immediately observable phenomena to which signals refer (Seyfarth & Cheney 1980, 1990).

 

Project Design and Implementation

Study site. This study was based at a World Wildlife Fund camp site in the Dzanga-Ndoki Park located approximately 13 km from Bayanga, a small town in the Central African Republic. For the last five years, Andrea Turkalo has studied forest elephants based near this site. I initially collected data at the Dzanga clearing, an open circle of various shrubs and mud (200-300 m in diameter) located in the forest approximately 4 km from the camp site. This clearing is a foraging area for not only large mammals such as elephants and antelope but also birds, including hundreds of African Grey Parrots. I observed and recorded African Grey Parrot behavior from a large tower (constructed and used by WWF for tourists) and also a smaller blind (constructed by two pygmies who worked for me); the two structures were separated a short distance from each other along on the southern edge of the clearing. Additionally, I observed African Grey Parrots at two nest cavities (found by my pygmy employees) in trees located near the road into the Dzanga-Ndoki Park (within the Dzanga-Sangha Reserve).

 

Ethogram. The primary objective of this study is an ethogram, or systematic behavioral inventory. An ethogram consists of (a) a detailed list of all behavioral elements that occur in a given context and (b) guidelines for assignment of and discrimination between elements (Figueredo, Ross & Petrinovich 1992). In order to have a general outline for field work, Vanya Jackson and I previously designed and collected data to develop an ethogram for ten captive African Grey Parrots housed together in a 4.4 x 2.2 x 1.9 m3 cage, located at the home of a parrot breeder in Tucson, Arizona. I adapted this ethogram's design for my study of African Grey Parrots in their natural habitat in Dzanga-Sangha Reserve.

The captive African Grey Parrot ethogram was designed and is being developed as follows. First, we performed preliminary observations of behavior exhibited by each individual at various times (e.g., early morning, midday, late afternoon). Preliminary observations enabled us to designate baseline categories and specify categorical boundaries. This process included identifying, naming, and defining behavioral elements based on (1) observations of the ten wild-caught subjects, (2) observations of three captive African Grey Parrots in Dr. Irene Pepperberg's lab (University of Arizona), (3) a Thick-billed Parrot ethogram (Koenig 1994) and (4) and a Zebra Finch ethogram (Figueredo et al. 1992). Adaptation will include adding, deleting, and modifying definition elements or whole categories. Once categories and their definitions are complete (see Appendix for current list), I will quantify the ethogram.

The observation method, One-Zero Focal Animal Sampling, is also adapted from that of Koenig (1994) and Figueredo et al. (1992). The observer selects an individual bird and records its behavior during a five-minute sampling period. This period is separated into 30-second intervals. If any of a number of pre-specified behaviors occur one or more times during the 30-second period, the observer records a frequency of one for each observed behavior. If a behavior does not occur, the observer records a frequency of zero. At the end of the 5 minute sample, the observer tallies the one-zero scores for each behavior. This tally shows the "proportion of 30 second time periods during which a specified behavior" occurs (Koenig 1994). In addition to recording the behavior of the focal animal, the observer also records any behavior directed toward the focal animal. Five minute observation periods are repeated with new randomly chosen focal animals for as long as a group remains at a locale.

I am adapting the captured African Grey Parrot ethogram for studying free-living African Greys in Africa as follows. First, I will use written, videotaped, and audiotaped observations of behavior exhibited by various free-living individuals at various times (e.g., morning and afternoon) and in various locations (e.g., clearing and nest cavities) to add, delete and modify categorical definitions and to re-specify categorical boundaries. Second, I will use the newly outlined behavioral elements to quantify the ethogram (Dr. A. J. Figueredo, pers. comm.). Quantification will involve analysis of videotape by two undergraduate students at the University of Arizona and myself; this type of analysis will ensure inter-rater reliability. Videotaped samples of the behavior were recorded with a Sony TR400 Hi8 millimeter video camera recorder .

 

Audio Recordings. I recorded vocalizations at the clearing and at two active nest cavities with a directional Sennheiser MKH 70 P48 microphone and a Marantz PMD 221 tape recorder. I made most of the recordings simultaneously with various segments of videotape.

 

Natural History Data Collection. Some natural history data collection (e.g., information on reproduction, diet, mortality, and habitat) is either directly related to or inherent in the process of developing the ethogram. For example, I was able to videotape some nesting behavior; ethogram analysis will provide information on the frequency and variability of reproductive behavior and the time of breeding season. Observations of foraging African Grey Parrots enabled me to photograph various plants that they consume (for identification). I also observed behavioral responses of flocks to one or more raptor species; this behavior may be indicative of predator avoidance. Finally, contextual description including location of foraging areas and nest cavities will provide evidence for African Grey Parrot habitat requirements.

 

 

 

REFERENCES

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