NT Naturalist - Number 30, Published February 2021
ISSN: 0155-4093
Editor: Richard Willan
Pre-release Articles
| Download | 1. Fruiting season and seed germination of coastal vine forest species from East Point Recreational Reserve, Northern Territory, Australia |
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| Authors | Thusithana, Vidushi; Bellairs, Sean M.; Bach, Christine S. |
| Abstract | Fires, storms, cyclones and human activities impact coastal vine forest communities around Darwin. To restore these communities after such disturbance, information on the fruiting season and seed germination of native species is important for collecting and propagating their seeds. We studied the seasonal occurrence of fruiting and the requirements for seed germination of 19 coastal vine forest species in Darwin’s East Point Recreational Reserve. Fruiting and seeding were seasonal, nine species set fruit during the Wet season and 10 species set fruit during the Dry season. Seed fall lagged by two or three months behind fruiting. Thirteen of the species did not have any seed dormancy and five species were treated to break dormancy. With the application of the most effective germination treatment, two species started to germinate within two days, and all except two species commenced germinating within 14 days. Maximum germination of all species had occurred within 30 days. Because dispersal of mature seeds of most species occurs over only one or two months each year, fire impacts prior to dispersal could disrupt seed availability for at least one year. |
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| Download | 2. A citizen science project in Ludmilla Bay, Darwin Harbour, helps identify invertebrates that fuel shorebird migration |
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| Authors | O’Dea, Anne; Winderlich, Steve |
| Abstract | The major aim of a citizen science project undertaken by Conservation Volunteers Australia was to increase knowledge and awareness of the shorebirds and the invertebrates that they rely on for food during their epic annual migratory journeys. Shorebirds were counted at ‘Shorebird 2020’ sites at Ludmilla Bay in Darwin Harbour during a count in 2018. A total of 897 individuals of 15 species of shorebirds (plus 59 individuals of 6 other vertebrate species) were recorded. Invertebrate samples were taken from 21 sites spread across Ludmilla Bay and from low to high tide at the same time of year. In total 63 samples were taken from 21 sites for invertebrates and they yielded a total of 34 species-level taxa. Taxa of annelids, molluscs, crustaceans, echinoderms, cnidarians, brachiopods and nemerteans were recorded. The invertebrate diversity was higher at either end of Ludmilla Bay, particularly around East Point at the northern end. Involving volunteers in this citizen science project was a key to its success in achieving its goals, including increasing awareness about these low-profile invertebrate and bird species. A total of 53 volunteer days were contributed by participants in this project, equating to over 400 person hours. |
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| Download | 3. A population of the rare Northern Shrike-tit that forages and breeds in a seasonally inundated paperbark woodland in Arnhem Land, Northern Territory |
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| Authors | Noske, Richard A. |
| Abstract | The vast majority of records of the Northern Shrike-tit (Falcunculus whitei) in the Top End of the Northern Territory are from eucalypt woodlands in inland localities, mostly in the Katherine-Maranboy region, approx. 250 km from the nearest coastline. This report summarises observations of a small resident population of these rare birds which is largely confined to a paperbark woodland on the seasonally inundated floodplain of the Tomkinson River, a tributary of the Liverpool River, only 17–35 km from the coast of western Arnhem Land. The population is apparently isolated and small (8–50 pairs) with a relatively low density (est. 0.01 birds ha-1), and given its existence since at least 2000, appears sustainable. These birds forage mainly on Broad-leaved Paperbark (Melaleuca viridiflora), in which they obtain arthropod prey from both leaves and bark. Nest-building was observed in September and October, and dependent juveniles were present in two territories in early March. One nest was built in a paperbark tree, the lowest nest height (6.5 m) reported for the species to date and the first in a non-eucalypt. Vocalisations of birds in this population differed from those described and recorded in the literature for the species. Although it has been argued that the scarcity of this species in northern Australia is due to the paucity of eucalypt species that shed their bark annually, both the Tomkinson River population and some populations of the species’ two congeners forage partly, or even largely, on foliage. |
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| Download | 4. New localities for nine bird species in Arnhem Land, including those for the notable Gouldian Finch, Red Goshawk and Hooded Robin |
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| Authors | Noske, Richard A. |
| Abstract | Due to its remoteness and restricted access, Arnhem Land remains one of the least ornithologically explored regions of Australia. This paper documents records of nine bird species which result from bird tours and surveys in the area surrounding Arnhem Land Barramundi Lodge, south of Maningrida, western Arnhem Land, from 2008 to 2018, and assesses their significance based on the historical literature, two national bird atlases and online database records. Three species, Red Goshawk (Erythrotriorchis radiatus Accipitridae), Rufous Owl (Ninox rufa Strigilidae) and Gouldian Finch (Chloebia gouldiae Estrildidae), are historically known from localities to the west (Gunbalanya and King River) and east (Gove Peninsula), so their presence in the study area might be expected. Observations of two nesting pairs of Red Goshawks represent the first breeding records of this rare species for Arnhem Land. Annual sightings of predominantly juvenile Gouldian Finches and a record of recently-fledged birds suggest local breeding. Four other species, Hooded Parrot (Psephotellus dissimilis Psittaculidae), Yellow-tinted Honeyeater (Ptilotula flavescens Meliphagidae), Black-chinned Honeyeater (Melithreptus gularis laetior Meliphagidae) and Hooded Robin (Melanodryas cucullata Petroicidae), are largely known in the Top End from the semi-arid Katherine-Mataranka region, and the near-coastal observations documented here represent considerable extensions of the geographical ranges of all but the Hooded Parrot. All four species were associated with the seasonally-inundated paperbark woodland of the Tomkinson floodplain, though only the Yellow-tinted Honeyeater was abundant. The small population of Hooded Robins appears to be highly isolated and thus vulnerable to local, if not regional, extinction. Finally, I summarise records of the Mangrove Grey Fantail (Rhipidura phasiana Rhipiduridae) and the migratory Grey Fantail (Rhipidura albiscapa Rhipiduridae) in Arnhem Land, which help to define their ranges in the Top End of the Northern Territory. |
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| Download | 5. Red flags in a sea of green |
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| Authors | Lowe, Lynette |
| Abstract | This article covers the author’s experiences over many years, with invertebrates in general and with the spectacular and enigmatic Leichhardt’s Grasshopper (Petasida ephippigera) (Orthoptera: Pyrgomorphidae) in particular. It recalls her initial introduction to CSIRO, then employment with this organisation in Kakadu National Park, then ‘falling for’ Petasida ephippigera, and finally her own studies on it at Davidson’s Arnhem Land Safaris on the Cooper Creek system at Mount Borradaile. Many questions flow on from these initial observations, particularly the relationship between this insect and fire. |
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| Download | 6. What to grow: An annotated list of native larval food plants of butterflies and diurnal moths in the Darwin region, Northern Territory |
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| Authors | Braby, Michael F.; Westaway; John |
| Abstract | An annotated list of native larval food plants (131 species) of butterflies and diurnal moths (92 species) is provided for the Darwin region. We also collate information on the broad habitat, life form, plant part eaten, and method of cultivation for each species of food plant. Mistletoes, shrubs, herbs and grasses are predominately used in savannah woodland, whereas trees and vines are mainly exploited in monsoon vine forest and semi-deciduous monsoon vine thicket. All plant parts are eaten, but larvae of most species feed on leaves or the soft, new growth of young leaves. While the larvae of most butterflies/diurnal moths feed on several plant species, at least 26 species are known, or suspected, to feed only on a single species of native plant in the Darwin region. The compilation of such a list of indigenous food plants is to encourage further establishment of these species, particularly in suburban gardens, parks and roadside verges, to attract local butterflies and diurnal moths, thereby enhancing insect biodiversity in the urban landscape. |
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| Download | 7. Gastropod-like caterpillar cases on Turkey Bush |
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| Authors | Brown, Graham R. |
| Abstract | Illustrations of three stages (larva, pupa, adult) of the life cycle of the xyloryctid moth Plectophila sp. are provided. The larva constructs a helical case solely on Turkey Bush (Calytrix exstipulata) in the Top End of the Northern Territory. The full life cycle and other aspects of the biology of this species are unknown. |
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| Download | 8. Observations on relocation of a nest by a colony of Red Honey Ants (Melophorus bagoti) |
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| Authors | Deeti, Sudhakar; Cheng, Ken |
| Abstract | The desert-dwelling Australian Red Honey Ant (Melophorus bagoti) rarely moves from one nest site to another. We observed the relocation of one colony of this ant at a field site about 10 km south of Alice Springs. This relocation, which was 36 m from the old nest, took 17 days to complete with the relocation of the brood itself taking only 1 to 2 days. During this unexpected move, we observed a large amount of outdoor activity by guard ants and physical contact between guard ants, as well as between guard ants and foragers. This amount of contact between the guard ants and foragers has never been described before. The relocation apparently resulted from experimental changes around the nest site above ground, a conclusion that differs from that of the only other study on this species which suggested that interference with the actual nest underground triggered the relocation. |
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| Download | 9. A conspectus of the freshwater molluscs of the Daly River catchment, Northern Territory |
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| Authors | Willan; Richard C.; Kessner, Vince |
| Abstract | This article presents a summary of knowledge for all the known (and predicted) species of freshwater molluscs from the Daly River catchment – a total of 32 species in 11 families. A common theme is that the taxonomy of many of these species is unsettled because it is based only on shells so genetic studies are now necessary to determine biological species for their management and for land use. Five species are considered as endemic to the Daly River catchment and this represents the highest number of endemic/short range taxa for any drainage basin in the Northern Territory. A further three species occur in adjacent countries in Southeast Asia but nowhere else in Australia. There is only one anthropogenically introduced species. Qualitative field observations by us between 1978 and 2019 have not indicated a decline in the abundance of any species, but the plans to develop the region and increase agriculture in the catchment (in particular cotton growing) could pose a long term risk to these environmentally sensitive molluscs. |
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| Download | 10. Observations on the gastropod prey of Chicoreus capucinus (Gastropoda: Muricidae) in Darwin Harbour mangroves |
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| Authors | Bourke, Adam. J. |
| Abstract | Seven opportunistic field observations within mangrove forests in Darwin Harbour revealed that the muricid snail Chicoreus capucinus feeds upon relatively large, mobile gastropods and seemingly engages in higher rates of aggregative feeding (prey-sharing) behaviour than its counterparts in Southeast Asia. Field observations and evidence of prey-sharing from drill holes recorded on dead shells indicate that aggregative feeding by C. capucinus is associated with at least three gastropod prey species. A record of attempted cannibalism and multiple incidences of aggregative feeding suggest the availability and accessibility to gastropod prey is somehow limited in Darwin Harbour mangroves. Further detailed studies are, however, needed in order to prove this supposition. |
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| Download | 11. Book Review: Fire: A Brief History. Second edition |
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| Authors | Willan; Richard C, |
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