On 5 September 1987 I found a Syzygium sp (Myrtaceae) tree in flower, beside the boundary trail in Varirata National Park (Central Province) at c. 750 m. The tree was c. 30 m tall and had a large spreading canopy. It stood on the bank of the stream, in the bottom of a steep sided, relatively narrow valley. The flowers occurred in clusters growing directly from the sides, not at the ends of the branches, and did not grow from smaller twigs. The clusters consisted of many stalks, almost mistletoe-like, with each stalk supporting a flower. These clusters were about 15 cm in diameter. The stalks on which the flowers grew were quite woody and would support a bird the size of a Helmeted Friarbird Philemon buceroides.
Between 5 and 20 September 1987 I visited the tree four times and watched for a total of 520 minutes (5 September 15:00 - 16:45; 12 September 07:45 - 08:10; 13 September 08:45 - 11:30 and 20 September 07:00 - 10:45). The shortest observation period was 25 minutes and the longest 225 minutes. There were many fewer flowers on 20 September, the last visit, than on the first, although I cannot quantify this. I observed the tree from a convenient point on the ground, from where 70% of the canopy was visible. Although the tree was in leaf, the foliage was sparse and it was only the crown of a smaller tree that obscured my view.
Nine species, six honeyeaters (plus one unidentified meliphaga) and two lories were observed feeding at the flowers of this Syzygium tree. Feeding birds were present in the tree for 85% of the observation time, which included all of the first three observation periods. Only during the final observation period, when there were fewer flowers, were there times when there were no birds feeding in the tree.
Between one and four Helmeted Friarbirds were present throughout the first three observation periods. On 20 September two birds made only a brief visit to the tree to feed. Helmeted Friarbirds were present in the tree for 57% of the observation period and during this time at least one bird was at a flower cluster apparently feeding. While in the tree, the friarbirds moved from flower-cluster to flower-cluster by hopping along the branches or flying from branch to branch. When feeding the friarbirds perched by, or on the flower cluster, using their long necks and bills to reach the more inaccessible flowers. Although there were many flowers on each cluster, the friarbirds fed from only a few before moving onto the next cluster, so the time spent at each cluster was short, usually less than two minutes. Even when four friarbirds were in the tree together no intraspecific aggression was noted, although the birds seemed to keep in pairs. When a single bird was alone in the tree it called almost continuously.
Greater Streaked Lories Chalcopsitta scintillata were not recorded on the first visit but were seen on the subsequent three visits. Between two to eight birds (one to four pairs) were noted. They were present in the tree for 19% of the observation time. On approaching and leaving the tree the birds were noisy but were mostly quite while feeding. They moved from flower-cluster to flower-cluster by walking along the branches. On the flower-clusters they moved acrobatically from flower to flower, hanging upside-down to reach the more inaccessible ones. They did not appear to damage the flowers, i.e. they were not flower predators. No intraspecific aggression was noted and although competing for the same resource no interspecific aggression with the friarbirds was recorded.
Western Black-capped Lories Lorius lory were present in the tree for 35 minutes (7% of the observation time). Two to four were recorded feeding in the tree. They were not seen in the tree at the same time as the Greater Streaked Lories. As with the Greater Streaked Lories they were mainly quiet while feeding, but noisy when flying to and from the tree. They were also more acrobatic than the Helmeted Friarbirds when feeding at the flower clusters.
The remaining six species, all honeyeaters, which visited the Syzygium tree to feed, did so only briefly. Each feeding visit lasted less than a minute, with the birds usually only feeding at one or two flower-clusters as they passed through the tree. These six species made 13 feeding visits to the tree. Three species made five feeding visits on 5 September and four species, plus an unidentified meliphaga made eight feeding visits on 20 September. On 5 September one Tawny-breasted Honeyeater Xanthotis flaviventer, two Puff-backed Meliphagas Meliphaga aruensis and one Dwarf Honeyeater Oedistoma iliolophus passed through the tree with a mixed-species feeding flock. A single Tawny-breasted Honeyeater had also been recorded earlier in the first observation period. On 20 September an unidentified meliphaga and a Red-throated Myzomela Myzomela eques were with a party that also included two Helmeted Friarbirds and also fed on the Syzygium flowers. One male Papuan Black Myzomela Myzomela nigrita, two Mimic Meliphagas Meliphaga analoga and two Tawny-breasted Honeyeaters moved through the tree with another mixed-species feeding flock later in the day. No interspecific aggression was noted among the species that made up these flocks, possibly because the smaller species were inhibited by the presence of the Friarbirds. Only when the numbers of flowers were much reduced, on 20 September and the friarbirds only noted briefly, were the smaller birds recorded more frequently.
I would like to thank Jenny Hicks and Barry and Lynda Hopkins who helped with the observations and Helen Fortune Hopkins and Mike Hopkins who commented on an earlier draft of this note.
Between 5 and 20 September 1987 I visited the tree four times and watched for a total of 520 minutes (5 September 15:00 - 16:45; 12 September 07:45 - 08:10; 13 September 08:45 - 11:30 and 20 September 07:00 - 10:45). The shortest observation period was 25 minutes and the longest 225 minutes. There were many fewer flowers on 20 September, the last visit, than on the first, although I cannot quantify this. I observed the tree from a convenient point on the ground, from where 70% of the canopy was visible. Although the tree was in leaf, the foliage was sparse and it was only the crown of a smaller tree that obscured my view.
Nine species, six honeyeaters (plus one unidentified meliphaga) and two lories were observed feeding at the flowers of this Syzygium tree. Feeding birds were present in the tree for 85% of the observation time, which included all of the first three observation periods. Only during the final observation period, when there were fewer flowers, were there times when there were no birds feeding in the tree.
Between one and four Helmeted Friarbirds were present throughout the first three observation periods. On 20 September two birds made only a brief visit to the tree to feed. Helmeted Friarbirds were present in the tree for 57% of the observation period and during this time at least one bird was at a flower cluster apparently feeding. While in the tree, the friarbirds moved from flower-cluster to flower-cluster by hopping along the branches or flying from branch to branch. When feeding the friarbirds perched by, or on the flower cluster, using their long necks and bills to reach the more inaccessible flowers. Although there were many flowers on each cluster, the friarbirds fed from only a few before moving onto the next cluster, so the time spent at each cluster was short, usually less than two minutes. Even when four friarbirds were in the tree together no intraspecific aggression was noted, although the birds seemed to keep in pairs. When a single bird was alone in the tree it called almost continuously.
Greater Streaked Lories Chalcopsitta scintillata were not recorded on the first visit but were seen on the subsequent three visits. Between two to eight birds (one to four pairs) were noted. They were present in the tree for 19% of the observation time. On approaching and leaving the tree the birds were noisy but were mostly quite while feeding. They moved from flower-cluster to flower-cluster by walking along the branches. On the flower-clusters they moved acrobatically from flower to flower, hanging upside-down to reach the more inaccessible ones. They did not appear to damage the flowers, i.e. they were not flower predators. No intraspecific aggression was noted and although competing for the same resource no interspecific aggression with the friarbirds was recorded.
Western Black-capped Lories Lorius lory were present in the tree for 35 minutes (7% of the observation time). Two to four were recorded feeding in the tree. They were not seen in the tree at the same time as the Greater Streaked Lories. As with the Greater Streaked Lories they were mainly quiet while feeding, but noisy when flying to and from the tree. They were also more acrobatic than the Helmeted Friarbirds when feeding at the flower clusters.
The remaining six species, all honeyeaters, which visited the Syzygium tree to feed, did so only briefly. Each feeding visit lasted less than a minute, with the birds usually only feeding at one or two flower-clusters as they passed through the tree. These six species made 13 feeding visits to the tree. Three species made five feeding visits on 5 September and four species, plus an unidentified meliphaga made eight feeding visits on 20 September. On 5 September one Tawny-breasted Honeyeater Xanthotis flaviventer, two Puff-backed Meliphagas Meliphaga aruensis and one Dwarf Honeyeater Oedistoma iliolophus passed through the tree with a mixed-species feeding flock. A single Tawny-breasted Honeyeater had also been recorded earlier in the first observation period. On 20 September an unidentified meliphaga and a Red-throated Myzomela Myzomela eques were with a party that also included two Helmeted Friarbirds and also fed on the Syzygium flowers. One male Papuan Black Myzomela Myzomela nigrita, two Mimic Meliphagas Meliphaga analoga and two Tawny-breasted Honeyeaters moved through the tree with another mixed-species feeding flock later in the day. No interspecific aggression was noted among the species that made up these flocks, possibly because the smaller species were inhibited by the presence of the Friarbirds. Only when the numbers of flowers were much reduced, on 20 September and the friarbirds only noted briefly, were the smaller birds recorded more frequently.
I would like to thank Jenny Hicks and Barry and Lynda Hopkins who helped with the observations and Helen Fortune Hopkins and Mike Hopkins who commented on an earlier draft of this note.
No comments:
Post a Comment