Research

 

 

A Pilot Observational Study of Parma Wallabies (Macropus parma)

at Yengo Gardens, Mt. Wilson, New South Wales, Australia

 

Adrienne Miller & Russell Menard; Roger Williams Park Zoo, Providence, RI

 

 

Overview:

The parma wallaby (Macropus parma) inhabits dense sclerophyl forest, exiting the safety of the bush only at dusk and dawn for feeding. They are very shy and easily startled, causing them to disappear into the thick understory. The species is small (females average 3.2 – 4.8 kg, males average 4.1 – 5.9 kg) and predominantly a soft brown, with white on the neck and chest. All these factors make the species very difficult to observe in the wild. This fact was reinforced during our spring 2002 trip when we worked with New South Wales National Parks and Wildlife rangers and the species coordinator in an unsuccessful attempt to spot the species in the wild. Most of the literature on the parma wallaby comes from work done by G. M. Maynes in the 1970s. The most recent published scientific works were by D. Read and b. Fox in the early 1990s when he analyzed the habitat of parma wallabies and tried to determine if fecal pellets were a reliable means of identifying population size (they were determined not to be) and a 1998 behavioral study at Macquarie University, NSW, by T. Ord, C. Evans and D. Cooper.

 

An ethogram for Macropodidae was developed by G. Coulson, and T. Ord listed behaviors for a 1998 captive study, but there is not one specific to the parma wallaby for more natural environments. Once developed, our parma wallaby ethogram will be available to all zoological institutions housing parmas, as well as being posted on the Behavior Advisory Group’s ethogram Web site (www.ethograms.org).

 

The Yengo Gardens parma wallaby sanctuary was established in 1968 from descendents of animals introduced to Kawau Island, New Zealand in the 1870s. The sanctuary has supplied most of the parma wallabies held in Australian zoos. The sanctuary offers an observational opportunity not available anywhere else. It contains the most parma wallabies held in captivity anywhere (~150) within a twelve-acre enclosure. This containment allows the parmas to be observed with as little disturbance of natural behaviors as possible.  In field research the observer is rarely completely invisible and can have a profound effect on the subjects, altering their behavior in subtle ways. This colony has been exposed to intermittent observation from individuals and groups brought through the reserve. In addition, three of the other macropod species that would normally be associated with the parma wallaby in the wild - the red-necked pademelon, the red-necked wallaby and the swamp wallaby are present in smaller numbers.  We have developed a close relationship with Peter Pigott, the owner of Yengo Gardens and a man integrally involved with the recent history of the parma wallaby. The sanctuary should remain available for studies in the future. All of these factors make Yengo sanctuary a perfect location for an observational study of the parma wallaby.

 

A pilot observational study of the species is important to 1) formulate questions and hypotheses, 2) determine the best recording methods and 3) determine the best recording measures. A trial of recording sessions can test behavioral categories and measurement techniques, plus help eliminate some preliminary observer drift that can occur in the early stages of observation. A period of preliminary observation provides an opportunity to develop the criteria used to develop each category in an ethogram. It also provides the raw material from which questions and hypotheses can be formulated.

 

It is anticipated that in 2004 we can conduct an extended behavioral study of the species at Yengo based on the findings of this pilot study.

 

Goals and Procedures for 2003:

  1. Make preliminary observations and formulate hypotheses

  2. Make predictions from these hypotheses

  3. Identify which behavioral variables need to be observed or measured to test these hypotheses

  4. Create an ethogram of behaviors on the parma wallaby [and possibly on the additional species also present: red-necked pademelon (Thylogale thetis), red-necked wallaby (Macropus rufrogriseus) and swamp wallaby (Wallabia bicolor)]

  5. Determine the best measure of behavior  (i.e. latency, frequency, duration or intensity) or a combination of one or more

  6. Determine the best sampling type (i.e. ad libitum, focal, scan or behavior)

  7. Define the study area, possibly develop a map or graph

  8. Obtain estimated population numbers of each species

  9. Determine if continuous recording or time sampling is the best recording method

  10. Determine the best recording medium.

  11. Develop the specific questions we would like answered - develop a clear

  12. idea of the general issues to be answered - determine if there is a particular behavior to be observed

  13. Determine suitability of the colony for further studies (e.g. genetics, maternal behavior, habitat preference)

  14. Collect additional video footage for completion of parma wallaby video for use in North America and Australia.

 

Goals for 2004:

  1. Collect behavioral data at Yengo

  2. Analyze data post fieldwork

 

Procedure:

  1. Determine Between Observer Reliability.  Because two observers (Adrienne Miller and Russ Menard) will be studying the species behavior, it will be important to determine that we are obtaining similar results when observing the same behavior. The aim is for 1) each of the two observers to illustrate consistent recording on different occasions, and 2) each observer to record the same behavior in the same way. We will achieve reliability by doing simultaneous observations and comparing results until we obtain at least 85% reliability.

  2. Develop a species specific ethogram of parma wallabies. It is important to develop a detailed and complete definition of each category and the appropriate recording method before actually collecting the data. I have contacted T. Ord to see if they developed an ethogram for their 1998 study.

  3. Make observations on a predetermined schedule to avoid bias of simply recording something interesting or novel. For the preliminary/pilot study we will try to make each part of the day equally represented by observing at dawn, noon, dusk and possibly after dark.

  4. Experiment with different types of measures to determine the most appropriate measure. Frequency (the number of occurrences of the behavior pattern per unit time) and duration (the length of time the behavior last) will probably be considered. Intensity may or may not be considered.

  5. Define a group of animals (if applicable) by accessing how the animals are distributed in space and observing the relative distances between individuals.

  6. Experiment with different sampling types such as ad libitum (simply noting what is visible and seem relevant at the time), focal (observing one individual for a specified amount of time [this may be difficult due to the animals not being individually identified]), scan (rapid scanning of the entire group) or behavior (watching the group for a particular behavior). Use continuous recording to measure behavior to provide a time record for comparison and development of an appropriate sample interval if time sampling is determined to be the most appropriate recording rule.

  7. Experiment with various recording mediums such as audio and video (the creation of a video on the species is one of the ultimate goals of this project), verbal descriptions (this may possibly be used as a backup for detailed observations and especially important during a pilot study or in bad weather which may be encountered during this time period), and check sheets (which may be the simplest once an ethogram is developed). Automatic recording devices and computer event recorders may be considered for subsequent studies.

 

Timeline:

Week One:

  1. Continuous observation of animals. It is anticipated that two to four daily observation periods of one to two hours duration each will be undertaken at this stage.

  2. Acclimate animals to presence of observers

  3. Compare observations for the finalization of an ethogram

  4. Determine most appropriate observation points within the enclosure

 

Week Two:

  1. Finalize an ethogram for observed behaviors

  2. Finalize a check chart for behaviors described in the ethogram

  3. Determine sampling type and sampling intervals

  4. Determine appropriate times of day for observations

  5. Determine length of observation periods

 

Weeks Three and Four:

  1. Test ethogram and check chart

  2. Test recording methods

  3. Test everything determined in Weeks 1 and 2

  4. Determine Between Observer Reliability by observing the same individuals during the same time frame while making independent notations. These notations will be compared afterward and similarities and variances evaluated.

 

Potential Week Five (Russell will be there alone)

  1. Data accumulation for preliminary analysis

 

Equipment:

Two walkie talkies

Two binoculars

            Video camera

            Tape recorder

            Two tripods (with fluid head)

            Two beepers or countdown timers

            Computer

            Data sheets

            Paper and pencils

Two Night vision goggles

 

Possible Questions:

  1. Interaction between individuals

  2. Interaction between species

  3. Time budget for species

  4. Confirm behavior as solitary or communal

  5. Determine activity levels

  6. Determine habitat preference

  7. Determine if there is a dominance hierarchy and if it is linear or fluid.

  8. Determine if there are preferred associations between individuals by defining indices of association (one or more animals that prefer to associate with each other) and maintenance of proximity (what individual is actually responsible for maintaining this association).

  9. Use of the body “quiver”

  10. Bipedal movement of rear legs

  11. Further the nocturnal studies of T. Ord (1998)