Meyer’s Parrot Poicephalus meyeri is the smallest of the nine Poicephalus
parrots, forming the P. meyeri superspecies complex with five congeners. Their distributional
range far exceeds any other African parrot, extending throughout subtropical Africa. Meyer’s
Parrots had previously not been studied in the wild, and therefore, gathering high-quality
empirical data on their behavioural ecology became a research and conservation priority. The
primary aim of the study was to correlate environmental (e.g. rainfall, habitat availability,
resource characteristics, food resource abundance and temperature) and social (e.g. inter- and
intra-specific competition, predation, and human disturbance) variables with aspects of their
ecology (e.g. flight activity, food item preferences, breeding activity, and group dynamics) to
evaluate the degree of specialization in resource use (e.g. trophic, nesting and habitat niche
metrics).
African deforestation rates are the highest in the world, resulting in twelve out of the
eighteen Meyer’s Parrot range states undergoing drastic loss of forest cover over the last 25
years. Most commentary on the population status of Meyer’s Parrots and other Poicephalus
parrots pre-dates this period of rapid deforestation In addition, over 75 000 wild-caught
Meyer’s Parrots and almost 1 million wild-caught Poicephalus parrots have been recorded in
international trade since 1975. Empirical data from this study was used to identify ecological
weaknesses (e.g. niche specialization or low breeding turnover) for evaluation within the
context of deforestation in the African subtropics. Baseline data on the breeding biology and
nest cavity requirements of Meyer’s Parrots was also necessary to assess the viability of
applying the conservative sustained-harvest model to African parrots. A unifying goal of this
study was to advance our knowledge of the ecology of African parrots and other
Psittaciformes by assessing the validity of current hypotheses put forward in the literature.
The Meyer’s Parrot Project was initiated in January 2004 on Vundumtiki Island in the
north-eastern part of the Okavango Delta, Botswana. Due to high flood waters between
March and July 2004, road transects were postponed till August 2004. Transects were
conducted at Vundumtiki from August 2004 to July 2005 and February 2007 to August 2007,
and at Mombo from August 2005 to January 2006. During 480 road transects over 24
months, food item preferences closely tracked fruiting and flowering phenology, resulting in
significant positive correlations between Levins’ niche breadth, rainfall and food resource
availability. Meyer’s Parrot can, therefore, be considered opportunistic generalists predispersal
seed predator that tracks resource availability across a wide suite of potential food
items, including 71 different food items from 37 tree species in 16 families. Meyer’s Parrots
were, however, found to be habitat specialists preferring established galleries of riverine forest
and associated Acacia-Combretum marginal woodland. These strong habitat associations
facilitate their wide distribution throughout the Kavango Basin, Linyanti Swamps, down the Zambezi valley, up along the Rift Valley system in associations with the great lakes, through
the Upper Nile and the Sudd, and west as far as Lake Chad through the Sahel.
Seventy-five nest cavities were measured during this study, including 28 nest cavities
utilized by Meyer’s Parrots within the 430ha sample area at Vundumtiki. Over 1700 hours of
intensive nest observations at six nest cavities was undertaken. Meyer’s Parrots formed
socially monogamous pair-bonds maintained over at least four breeding seasons. Breeding
pairs established breeding territories up to an estimated 160ha within which there were 1–6
nest cavities. Eggs hatched asynchronously, yet nestlings fledged synchronously with similar
body size and condition. There was evidence to support the incidence of extra-pair
copulations, however, mitochondrial DNA sequence data are required to confirm the
incidence of extra-pair fertilizations. Meyer’s Parrots had no preferences in regard to nest tree
species beyond the incidence of suitable nest cavities, which are selected and further
excavated to accommodate their non-random nest cavity preferences. There was a significant
non-nesting Meyer’s Parrot population during the breeding season, likely due to this longlived
cavity-nester delaying nesting until a suitable breeding territory becomes available.
Meyer’s Parrots utilize communal roosts during summer and disperse from them
according to the Foraging Dispersal Hypothesis. Due to the requirement to roost during the
middle of the day to avoid heat stress, Meyer’s Parrots have bimodal flight and feeding
activity patterns. The highest probability of locating Meyer’s Parrots is between 08h30 and
11h00 during summer when both adults are feeding on the seeds of fleshy-fruits in riverine
forest communities.
Due to the paucity of data on the current distribution and population status of Meyer’s
Parrots and other African parrots, a continent-wide survey of all African parrots represents a
conservation priority. Current deforestation rates in several Meyer’s Parrot range, their
specialist habitat associations, and lack of evidence to support adaptability to a changing
landscape mosaic necessitate the re-classification of Meyer’s Parrots as data deficient or nearthreatened.
Based on low breeding population due to limited breeding opportunities, the
CITES Appendix II wild-caught bird trade should also be halted until the sustainability of this
trade has been evaluated and the relevant information made available. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/10836 |
| Date | January 2008 |
| Creators | Boyes, Rutledge Stephen. |
| Contributors | Perrin, Michael R. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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