Population, Nest Distribution, and Nest Characteristics of Great Egret in Pulau Rambut Wildlife Sanctuary, Jakarta Bay

Sekar Wilis Sudarsono; Ani  Mardiastuti; Yeni Aryati Mulyani

doi:10.18343/jipi.31.2.255

Authors

Sekar Wilis Sudarsono Department Forest Resources Conservation and Ecotourism, Faculty of Forestry and Environment, IPB University, IPB Darmaga Campus, Bogor 16680 Indonesia
Ani Mardiastuti Department Forest Resources Conservation and Ecotourism, Faculty of Forestry and Environment, IPB University, IPB Darmaga Campus, Bogor 16680 Indonesia
Yeni Aryati Mulyani Department Forest Resources Conservation and Ecotourism, Faculty of Forestry and Environment, IPB University, IPB Darmaga Campus, Bogor 16680 Indonesia

DOI:

https://doi.org/10.18343/jipi.31.2.255

Keywords:

Ardea alba, nest characteristics, Rhizophora mucronata, waterbird

Abstract

Pulau Rambut, a 45-hectare island in Jakarta Bay, is a major nesting and roosting location for waterbirds, especially the great egret (Ardea alba). This species has faced population constraints due to habitat loss, oil spills, and waste. Bio-ecological data on this species has been lacking. The purpose of this study was to quantify population size, analyze nest tree distribution, investigate nesting associations, and describe nest and egg features during the peak breeding season (March–April 2025). The birds were counted in the morning when they flew away and, in the evening, when they returned to the island. Nest trees were mapped, and nest tree attributes were assessed on trees discovered throughout the search. Field observations revealed an estimated 135 great egrets, mostly on the island's eastern side. Nests were mostly found in the uppermost canopy of Rhizophora mucronata (average height 13.8±2.3 m; diameter 20.0±7.1 cm; n = 19) and Rhizophora stylosa. Nests were cup-shaped, twig-based constructions measuring 46.8×38.5 cm with a depth of 42.3 mm. Purple herons (Ardea purpurea) were regularly observed to nest together. The clutch size averaged 2.2 eggs per nest (range: 1−4; mode: 2). The eggs were oval, pale blue-green, and averaged 50.9×35.8 mm in size, weighing 35.9±6.3 g (n = 19). These data represent the first thorough bio-ecological baseline for great egrets on Pulau Rambut. Conservation and restoration of mangrove ecosystems, particularly R. mucronata, is critical for sustaining great egret breeding numbers and minimizing future population decreases in the sanctuary.

Keywords: Ardea alba, nest characteristics, Rhizophora mucronata, waterbird

Downloads

Download data is not yet available.

References

Burger J. 1985. Habitat Selection in Temperate Marsh–nesting Birds. New York (US): New York Academic Pr.

Firdausy MS, Mardiastuti A, Mulyani YA. 2021. Abundance waterbirds and the distribution of trees nesting in Pulau Rambut (Rambut Island) Wildlife Sanctuary, Jakarta Bay, Indonesia. IOP Conference Series: Earth and Environmental Science. 771: 012028. https://doi.org/10.1088/1755-1315/771/1/012028

Kurnia I, Rifai BA, Febriyanti EN, Kardina JR, Azzahra RNA, Satriawan MH. 2024. Keanekaragaman jenis burung di Pulau Untung Jawa Kepulauan Seribu Provinsi DKI Jakarta. Jurnal Hutan Pulau-Pulau Kecil. 8(1): 1–10. https://doi.org/10.30598/jhppk.v8i1.12062

Lambrechts MM, Aime C, Midamegbe A, Galan M, Perret P, Gregoire A, Doutrelant C. 2011. Nest size and breeding success in first and replacement clutches: an experimental study in blue tits Cyanistes caeruleus. Journal of Ornithology. 153(1): 173–179. https://doi.org/10.1007/s10336-011-0722-1

Mardiastuti A. 1991. Difference in size among waterbird eggs in Pulau Rambut: Some preliminary observations. Media Konservasi. 3(2): 66–71.

Mardiastuti A. 1992. Habitat and Nest–site Characteristics of Waterbirds in Pulau Rambut Nature Reserve, Jakarta Bay, Indonesia [dissertation]. East Lansing (US): Michigan State University.

Mardiastuti A. 2001. Ecology of avian community of Pulau Rambut: Population, nest site distribution, and foraging site. Bogor (ID): IPB University.

Mardiastuti A, Mulyani YA, Susanti NKY, Ivonnie RN, Oktavia CA. 2020. Oil spill in Pulau Rambut and its possible long–term impact on mangrove as waterbirds habitat. IOP Conference Series: Earth and Environmental Science. 528: 012015. https://doi.org/10.1088/1755-1315/528/1/012015

Mardiastuti A. 2022. Waterbird community in Pulau Rambut Wildlife Sanctuary, Jakarta Bay: Review on species composition and population size after thirty years. IOP Conference Series: Earth and Environmental Science. 950: 012031. https://doi.org/10.1088/1755-1315/950/1/012031

Mashudi A, Marhento G. 2016. Identifikasi keanekaragaman jenis burung dan kearifan tradisional masyarakat dalam upaya konservasi di Pulau Rambut Kepulauan Seribu. Jurnal Formatif. 6(2): 119–124. https://doi.org/10.30998/formatif.v6i2.945

Park S, Kim K, Chung H, Choi YI, Sung H. 2011. Vertical nest stratification and breeding success in a six mixed–species heronry in Taeseong, Chungbuk, Korea. Animal Cells and Systems. 15(1): 85–90. https://doi.org/10.1080/19768354.2011.555119

Shin M, Lee E, Cho H. 2018. Estimating the potential habitat of breeding egrets and herons (family Ardeidae) for urban forest management in Daejeon Metropolitan City, Korea. Pakistan Journal Zoology. 54(5): 2069–2076. https://doi.org/10.20944/preprints201808.0065.v1