Comparative ecology of sympatric orange-fronted parakeets (Cyanoramphus malherbi) and yellow-crowned parakeets (C. auriceps), South Island, New Zealand

Sympatric orange-fronted (Cyanoramphus malherbi) and yellow-crowned parakeets (C. auriceps) were surveyed in a South Island beech (Nothofagusspp.) forest during the spring and summer of 1998/99. Habitat use, behaviour and diet were recorded for each parakeet identified. A single observer did all recording. Both species were seen most frequently in the upper-most 20% of the forest stratum. Orange-fronted parakeets were seen more frequently than yellow-crowned parakeets in the lowest 20% of the forest stratum. Orange-fronted parakeets were seen calling less frequently and comforting more frequently than yellow-crowned parakeets, and this may reflect a difference in breeding period behaviour. Both species were usually seen feeding. In summer, both species were seen feeding mostly on seeds, predominantly from mountain beech — but this was a beech mast year. The spring diet of both species appeared to be largely flowers and invertebrates. Orange-fronted parakeets were seen feeding on flowers less frequently and on invertebrates more frequently than yellow-crowned parakeets. We suggest factors that may have contributed to the decline in abundance of both species: (1) greater competition between the two species in a habitat substantially modified by humans; (2) competition with introduced finch species; (3) competition with wasps for invertebrates; and (4) vulnerability to introduced predators. These last two factors are likely to affect orange-fronted parakeets in particular, because they appear to feed more on invertebrates and make greater use of the ground and low-growing plants.