THAI FOREST ECOLOGICAL RESEARCH JOURNAL

The Importance of Natural Forest Gap on Migratory Birds in a Lower Montane Forest at Doi Suthep-Pui National Park

Supalak Siri¹, Yuwadee Ponpituk* ¹, Apisada Rueangket², Mongkol Safoowong³ and Prateep Duengkae⁴

¹Program in Forestry, the Established Project of College of Forestry, Maejo University Phrae Campus, Phrae 54140
²School of Agriculture and Cooperatives, Sukhothai Thammathirat Open University, Nonthaburi 11120
³Doi Chiang Dao Wildlife Research Station, Department of National Parks, Wildlife and Plant Conservation, Chiang Mai 50170
⁴Department of Forest Biology, Faculty of Forestry, Kasetsart University, Bangkok 10900

*Corresponding author: Email: yuwadee_ppt@mju.ac.th

DOI: https://doi.org/10.34044/j.tferj.2024.8.1.05

Abstract

Background and Objectives: Gaps in the natural forest create complexity within the forest structure, providing unique habitats that attract birds. The objectives aimed to examine the presence, body condition index, microhabitat selection (under closed canopy; UCC and forest gap; FG), and the influence of forest gap size on the abundance of capture migratory birds, Martens's Warbler (Phylloscopus omeiensis) and Bianchi's Warbler (Phylloscopus valentini) in lower montane forest (LMF) at Huai Kog Ma watershed, Doi Suthep-Pui National Park, Chiang Mai province.

Methodology: The study was carried out at LMF permanent plot, 400 x 400 m, and 12 mist net points were established to observe migratory birds in under FG and UCC areas. All captured birds were ringed tagged and monthly monitored for a total of 61 months, from October 2014 to October 2019.

Main Results: The survey results recorded 63 captures of the Martens's Warbler (P. omeiensis) from 45 individuals, and 79 captures of the Bianchi's Warbler (P. valentini) from 50 individuals, all marked with ring bands. Recapture data showed that both species returned to the same location up to three consecutive years. The stopover duration ranged of P. valentini had slightly longer than P. omeiensis, 5-8 and 3-7 months, respectively. Fat score assessments had increased during migration for P. omeiensis and P. valentini, 69% and 78%, respectively, indicating fat accumulated before they migrated back to their habitats. Habitat preference analysis revealed no statistical significant differences of species between FG and UCC. Additionally, forest gaps approximately 400 – 500 m2 were frequently utilized by these birds.

Conclusion: The natural succession creates forest gap with unique environments in LMF, providing the habitats and rejuvenate for migratory birds before return back to their original habitats.

Keywords: Fat; forest gap; migratory bird; montane forest; Phylloscopus