COSTS AND BENEFITS AMONG PARTICIPANTS IN MIXED. SPECIES FORAGING BIRD FLOCKS IN LOWLAND DECIDUOUS FORESTS, HUAI KHA KHAENG WILDLIFE SANCTUARY WICHYANAN LIMPARUNGPATTHANAKIJ A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE (ENVIRONMENTAL BIOLOGY) FACULTY OF GRADUATE STUDIES MAHIDOL UNIVERSITY 2014 COP}'RIGHT OF MAHIDOL UNIVERSITY Fac. ofGrad. Studies, Mahidol Univ. Thesis / iv COSTS AND BENEFITS AMONG PARTICIPANTS IN MIXED.SPECIESI FORAGING BIRD FLOCKS IN LOWLAND DECIDUOUS FORERESTS, HUAI KHA KHAENC WILDLIFE SANCTUARY WICHYANAN LIMPARLINGPATTHANAKIJ 5337750 SCEB/M M.Sc. (ENVIRONMENTAL BIOLOCY) TLIESIS ADVISORY COMMITTEE: JENJIT KHUDAMRONGSA' GEORGE ANDREW GALE. Ph.D, ABSTRACT This study focused on mixed-species flocks of birbirds in a lowland deciduous forest a habitat type threatened heavily in the regioegion, p marily from logging and clearance for agriculture, and which is understudied)d irin comparison with evergreell forests. Data on the composition and structure of a totaltor of 657 mixed- species foraging bird flocks were collected fi:om January to Decemcember, 2012 in Huai Kha Khaeng Wiidlife Sanctuary, Thailand. The flocks could be dividlivided into two types: those composed of small-sized birds and those composed of mediurrdium-sized birds. The species most prevalent in flocks included gregarious "leader"er" species, such as laughingtluLrshes (Garrulax spp.), the conspicuous anti-predaredator alalm-calling ''serltinel" species such as drongos (.Dictulus spp.). and the BlacBlack-naped Monarch (Hypothymis dzwea). Most species showed a lower mixed-flocking.ing propensity during the breeding seasot. Several species in medium-sized bird flocksrks showeds significant behavioral adiustments in which they foraged closer to the groundnd irin mixed flocks led by (ground-feeding) laughingthrushes. Four species of woo<,oodpeckers showed significantly iower vigilance rates when participating in mixed-spel-species flocks. Their vigilance rates were also negatively conelated with flock size. "SentSentinel" species sLlch xs the Greater Racket-tailed Drongo (D poradiseus). Ctow-biw-billed Drongo (D. utlnectans), and Black-naped Monarch showed higher prey-ca1r'-capture rates when ibraging in mixed-species flocks than when outside flocks. Tire.'he Ashy Drongo (r. letcophoeus), Crcater Racket-tailed Dro[go, and Crow-billedIed Drongo changed perching positions significantly more offen in mixed llocks than ouloutside mixed flocks. .\nong the fou. sentinel species, kleptoparasitism behavior was most lrequently obseNed in the Ashy Drongo (14.7% oftotal foraging events) andmd least freque[tiy i11 the Black-naped Monarch (11.50/o of total foraging events). A man'rmalmal species. the \\iestern St ped Squirel (Iaalops mcclellandii). associated closel)rsely with bird flocks, and was itsclf 'a much more frequent early a11ti-predator alarmn callerca than the four abovementioned conventionally accepted sentinels. Future studiesdies should focus on lirrther assessing the specific benelits and costs to each species fromrom their participatiorl in tlocks. KEY WORDS: MIXED-SPECIES FLOCK / HETEROSPECIFICIC ASSOCIATIONA / BIRD-WAVE / BEHAVIOML ADJUSTMEN,IFNT / SF,NTTNF,T, SPECIES / ANTI-PREDATOR VIG]LANCE 8l pages I tJ Fac ofGrad. Studies. Mahidol Univ. Thesis / v grarfrot :slordua rn nr::rr {rurroir"rffolo tln1rrtl ra ah1tl.- c o-tdr t1fl inu miu {do id r#r ottrtril COSTS AND BENEFITS AMONC PARTICIPANTS ]N M]XED.SPECIES FORAGINC BIRD FLOCKS 1N LOWLAND DECIDUOUS FORESTS, HUAI KHA KHAENC WILDLIFE SANCTUARY irqtiuri 6111!lrrioruio s337750 scEB/M 111. 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Studi€s, Mahidol Univ. M.Sc. (Environmental Biology) / l CHAPTER I COMPOSITION AN'D STRUCTURE OF AVIAN MIXI,D-SPECIES FORAGING FLOCKS IN LOWLAND DECIDUOUS FORESTS, IIUAI KHA KHAENG WILDLIFE SANCTUARY -{bstract The numbers and species of birds participating in avian mixed-species :i.raging flocks in lowland deciduous forest were rccorded for a total of 657 flocks :kouehout the year in Huai Kha Khaeng Wildiife Sanctuary, Thailand. Most flock ranicipants showed a high propensity to associate with birds of similar body size. Thus. flocks could be categorized into two main qpes, each compdsing different sets .ri regular mixed-flocking species: those with small-sized birds as core species and tose rvith medium-sized bird species as core species. Resident species participated in rni\ed-species flocks more when non-breeding visitors were present (Aug-Jan) and e\hibited a lower propensity to join mixed flocks during the breeding season (Feb- -lul). Distinct associations among particular species were identified and some engaged :n specific behavioral roles in the flock. Three species in medium-sized bird flocks, Creater Yellownape (Chrysophlegma flavinucha), Black-headed Woodpecker (Picrs .alht op)igius), and Greater Racket-tailed Drcngo (Dicntrus paradiseus) perched signiiicantly lower in mixed-species flocks led by the gregarious and terrestrial ..lughingthrushes (Garrla.r spp.) than outside mixed-species flocks. Most findings in r.eYious studies were supported: mixed-flock paficipants were attracted tojoin flocks ot similar-sized species, mixed-flocking propensity was low in breeding season, and -.me species showed behavioral adjustments when participating in mixed flocks. -{e)\\ords: Mixed-species flock, interspecific association, bird-wave, cluster analysis, :'eha!ioml adjustment \\ ichyanan Limparungpatthanakij Composition and Structure ofMixed-species Flocks / I0 :herc was only one height value per species during any given flock encounter. Al1 data rrere collected by the author. Therefore, consistency in measurements was €nsured to some extent. For each mixed-flocking species, the perching height preferences of individuals participating in ("inside') and or not paticipating in (.,outside,,) mixed- .pecies flocks were statistically examined using the non-parametric Wilcoxon rank- ium test, often refered to as Mann-Whitney U test. The tr'-test was also applied in orJer to assess the differences in variances. Nomenclature and taxonomy follow the checklist of Thai bird names, -:ruary 2012 (BIRD CoNSERVATToN SoclETy oF THATLAND REcoRDs CoMMr|trjrl :,r1li. Results Composition and structure of mixed-species foraging flocks Data on bird species pafiicipating in avian mixed-species foraging flocks .i.'re recorded for a total of 657 flocks throughout the year. A total of 37 out of 1 17 :-didate species were considered regular flocking species, having a mixed-flocking ::.'pensity exceeding 40% (Table 1.2). A few species seen rarely, but thoughr also to ^t possibly core-flocking species (e.g Bar-winged Flycatcher-shrike, Aerripa.e .:-dnrr. and Verditer Flycatcher, Eumyias thalassinus) were excluded from the :::l\iis as sample sizes were too small (Table 1.3). Flock types could be broadly -.:.'sorized by the range of body sizes of participating species into 268 flocks of ::::.1ll-sized birds, and 384 flocks ofmedium-sized birds (Table l.l). The remaining 5 :::red'species flocks could not be decisively categorized by size. The groupings in the :-iir diagram (Fig. 1.3) conelated well with body sizes and mixed-flocking ::. aensitv. Wichyanan Limparungpatthanaki j Composhion and Slructure ofMixed-species Flocks / 30 etlciency with variation in flock size and composition. Improvements in testi.g and analyzing behavioral interactions among participants in mixed-species flocks will lead to better understanding of species roles and adjustments to mixed flocks, especially in the fast-moving small-sized