Submitted for Behavioral & Conservation ecology – Original research in Oecologia

1 1Online Resource Submitted for: Behavioral & Conservation ecology – Original research in Oecologia 4Title: Understory avifauna exhibits altered mobbing behavior in tropical forest degraded 5by selective logging 6Running title: Avian mobbing behavior is altered by selective logging 7Authors: Fangyuan Huaa,b*, Kathryn E Sievingc a State Key Laboratory of BioControl, College of Ecology and Evolution/School of 9Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510275, China 10 b Program in Science, Technology and Environmental Policy, Woodrow Wilson 11School of Public and International Affairs, Princeton University, Princeton, NJ 08544, 12U.S.A 13 c Department of Wildlife Ecology and Conservation, University of Florida, 14Gainesville, FL 32611, U.S.A 15 * Corresponding author: E-mail - fhua@princeton.edu / hua.fangyuan@gmail.com; 16Phone - +1-609-258-0293; Fax - +1- 609-258-8880 17 Appendix Details of mobbing playback and data collection protocol 18A priori sample size estimation 19 Based on relatively high effect sizes for mobbing-related measures across habitats 20(e.g., Sieving et al 1996, 2000, 2004), we applied the following very conservative 21parameters in an a priori power analysis using G*Power (Faul et al 2007) to roughly 22estimate necessary sample sizes for behavioral sampling at mobbing aggregations 23(expected effect size = 0.25, power = 0.95, alpha = 0.05; omnibus one-way ANOVA, 24groups with fixed effects) Sample size thus produced would thus be higher than that 25produced from less conservative parameters We obtained an estimate that at least 250 26observations of individual birds would be needed across all sites Based on preliminary 27data, this sample size would be easily achievable from 30 points/site 28Playback stimuli for eliciting avian mobbing 29 We simultaneously used three stimuli to elicit forest birds’ mobbing behavior We 30used prey birds’ mobbing vocalization as the main stimulus, because the lowland 31rainforest of Southeast Asia lacks a predator species whose vocalization readily elicits 32avian mobbing (B van Balen and F Rheindt, pers comm.), while avian mobbing calls 33were known to effectively attract birds into inspection (Nocera et al 2008) and mobbing 34behaviors (Hurd 1996) This mobbing vocalization consists of the simultaneous, agitated 35mobbing/scolding vocalizations of the following species: spectacled bulbul Pycnonotus 36erythrophthalmos, buff-vented bulbul Iole olivacea, pin-striped tit-babbler Macronous 37gularis, dark-necked tailorbird Orthotomus atrogularis, and black-naped monarch 38Hypothymis azurea They all are small-bodied understory prey bird species that occurred 39at all of our study sites The recording was taken during a naturally occurring mobbing 40event in the lowland rainforest of northern Sumatra (Lamno, Aceh Province) and 41graciously provided by B van Balen The cause of the mobbing event was unclear, but 42was probably an avian predator (B van Balen, pers comm.) 43 We additionally used two supplemental stimuli from the Sunda Scops-owl Otus 44lempiji Simultaneously presenting its vocal and visual cues provided more realistic 45simulation of its presence and a focal point for avian mobbing (Sieving et al 2004) We 46used one recording of the owl’s typical territorial call from West Kalimantan (van Balen 472008), and a custom-made wooden model Importantly, the call was of the same dialect 48as the Sunda Scops-owls in our field site in Sumatra (F Hua pers obs.) 49 50 51Figure A1 Wooden model of the Sunda Scops-owl in perched posture used as the visual 52stimulus in playback 53 54 Literature cited 55Faul, F., Erdfelder, E., Lang, A-G Buchner, A 2007 G*Power 3: a flexible statistical 56 power analysis program for the social, behavioural, and biomedical sciences - 57 Behavior Research Methods 39: 175-191 58Hurd, C R 1996 Interspecific attraction to the mobbing calls of black capped 59 chickadees (Parus atricapillus) - Behavioral Ecology and Sociobiology 38: 287-292 60MacKinnon, J., and Phillipps, K 1993 A Field Guide to the Birds of Borneo, Sumatra, 61 Java, and Bali, the Greater Sunda Islands Oxford University Press, New York, NY 62Nocera, J J., Taylor, P D , Ratcliffe, L M 2008 Inspection of mob-calls as sources of 63 predator information: response of migrant and resident birds in the Neotropics - 64 Behavioral Ecology and Sociobiology 62: 1769-1777 65Sieving, K E., Willson, M F., de Santo, T L 1996 Habitat barriers to movement by 66 endemic understory forest birds in south temperate rainforest - Auk 113: 944-949 67Sieving, K E., Willson, M F., de Santo, T L 2000 Defining corridor functions for 68 endemic birds of south-temperate rainforest - Conservation Biology 14: 1120-1132 69Sieving, K E., Contreras, T A., Maute, K L 2004 Heterospecific facilitation of forest70 boundary crossing by mobbing understory birds in North-Central Florida - Auk 121: 71 738-751 72van Balen, B 2008 XC46912 Accessible at www.xeno-canto.org/46912 10 11 73 Appendix Details of mobbing intensity measurement 74 For focal sampling of behavioral conspicuousness, we tried to avoid double- 75observing the same bird individuals in two ways First, we tried to focal sample as large a 76collection of different bird species as possible during each playback session Second, 77when we focal sampled more than one individuals within the same species during a 78playback session, we kept mental notes of the movement direction of individuals already 79sampled, and only selected new conspecific subjects for focal sampling from parts of the 80bird mob that the individuals already sampled were unlikely to be in 81 For each bird under focal sampling, their presence in the mob and mobbing 82behaviors relevant to the five scoring aspects of mobbing conspicuousness were 83described and recorded by a voice recorder throughout the duration of the focal sampling 84span Such information was subsequently transcribed, in the form of (1) the number of 85times that the focal individual’s presence in the mob was noted (N1), and (2) the number 86of times each behavioral aspect occurred (N2), during the entire focal sampling span The 87relative values of these two numbers were then used to score the frequencies of the 88behavioral aspects Scores of and respectively represented behavioral aspects that did 89not occur (N2 = 0) and that occurred incessantly (N2 = N1 or was almost the same as 90N1); behavioral aspects that occurred only occasionally (N2/N1 < 0.2) were assigned a 91score of 1, while those that occurred relatively frequently (N2/N1 ≥ 0.2) were assigned a 92score of 93 For measuring approach propensity, because mobbing birds were not individually 94marked, we counted the largest number of individuals for each species that were observed 12 13 95approaching within the 15m and 3m scales at any point during the mobbing event This 96method may underrepresent the true number of individuals within the focal scales if 97multiple individuals took turns to approach within the focal scales, but should not 98introduce systematic bias across mobbing events or study sites 14 15 99 100 Appendix Details of vegetation structure measurement At each 10-m-radius circular plot centering on the sampling points, we measured 101canopy cover by standing at the plot center and taking the average of four readings at 102every 90°, with the location of the first reading chosen randomly We measured the 103understory vegetation density at three height levels (i.e., 3m, 4m, and 5m above ground) 104using a density board We held the density board vertical and counted the percentage of 105cells blocked by vegetation seen from 10m away Four samples were taken with the 106density board at the center of the 10-m radius plot (observer counting from a random 107position on the edge of the plot and then at the points equidistant from the first around 108the edge of the circle) Four other samples were taken (total of samples at each heights) 109with the density board placed at each of equidistant points on the edge of the 5-m 110diameter circular plot (first point position was chosen randomly) and the observer stood 111on the opposite edge of the 5-m diameter plot to read the density board We took the 112average of these eight readings for each height level to represent the average understory 113density of the plot at that height level (in percentage) We then averaged across these 114three height levels to obtain the average understory density at the sampling point in 115question 16 17 116 Appendix Assignment of species to understory gleaning and flycatching guilds 117 We assigned species as understory gleaning or flycatching species based on 118information in field guides (Smythies 1981, MacKinnon and Phillips 1993, 119Jeyarajasingam and Pearson 1999) and our field experiences To differentiate non120understory species that typically use forest strata other than the understory, such as the 121canopy or undergrowth, we followed the following principles (1) A species is considered 122an undergrowth species only if it typically skulks in bushes or other forms of 123undergrowth vegetation that are usually < 2m in height (2) If a species is noted by field 124guides as using more than one forest strata (i.e., canopy or undergrowth in addition to 125understory), we assigned it to the stratum that is more typically used according to our 126field experiences Similarly, where field guides had confusions about the assignment of 127understory species to the gleaning versus flycatching foraging techniques, we assigned 128the species to the foraging technique that according to our field experiences is more 129typically used The list of species belonging to the gleaning and flycatching guilds is 130provided in Appendix 131 18 19 132 Literature cited 133Jeyarajasingam, A., and Pearson, A 1999 A Field Guide to the birds of West Malaysia 134 and Singapore Oxford University Press, New York, NY, U S A 135MacKinnon, J., and Phillipps, K 1993 A Field Guide to the Birds of Borneo, Sumatra, 136 Java, and Bali, the Greater Sunda Islands Oxford University Press, New York, NY, 137 U S A 138Smythies, B E 1981 The Birds of Borneo Sabah Society with the Malayan Nature 139 20 Society, Kota Kinabalu and Kuala Lumpur, Malaysia 10 21 140 Appendix List of species that responded to mobbing playback 141Table A5.1 List of understory species that responded to mobbing playback by approaching within 15m from playback centre Number at each study site Inclusion in analyses† PRIM DEG1 DEG2 DEG3 Latin name Understory gleaning species Rufous piculet Checker-throated woodpecker Banded woodpecker Buff-necked woodpecker Red-eyed bulbul Spectacled bulbul Hairy-backed bulbul Grey-cheeked bulbul Cream-vented bulbul Grey-bellied bulbul Black-headed bulbul Black-crested bulbul Yellow-bellied bulbul Streaked bulbul Buff-vented bulbul Crested jay‡ Moustached babbler Chestnut-backed scimitar babbler Rufous-crowned babbler Scaly-crowned babbler Striped tit-babbler Brown fulvetta Chestnut-rumped babbler Black-throated babbler Sasia abnormis Picus mentalis Picus miniaceus Meiglyptes tukki Pycnonotus brunneus Pycnonotus erythrophthalmos Tricholestes criniger Alophoixus bres Pycnonotus simplex Pycnonotus cyaniventris Pycnonotus atriceps Pycnonotus melanicterus Alophoixus phaeocephalus Ixos malaccensis Iole olivacea Platylophus galericulatus Malacopteron magnirostre Pomatorhinus montanus Malatopteron magnum Malacopteron cinereum Macronous gularis Alcippe brunneicauda Stachyris maculate Stachyris nigricollis 22 Common name 11 0 25 46 10 15 0 47 11 0 0 0 21 12 23 12 10 17 1 0 5 1 0 30 10 44 20 10 19 0 11 1 1 59 37 21 22 16 0 4 2 21 10 12 | | | | | Δ 6 Δ 4 | | | | Δ Δ Δ 23 Grey-breasted babbler White-chested babbler Rufous-tailed shama Spotted fantail Ashy tailorbird Plain sunbird Purple-naped sunbird Malacopteron albogulare Trichastoma rostratum Trichixos pyrrhopygus Rhipidura perlata Orthotomus ruficeps Anthreptes simplex Hypogramma 0 5 13 0 3 19 0 0 | hypogrammicum Ruby-cheeked sunbird Anthreptes singalensis Little spiderhunter Arachnothera longirostra 36 10 1 | Δ Grey-breasted spiderhunter Arachnothera affinis 2 1 | Long-billed spiderhunter Arachnothera robusta 1 Crimson-breasted flowerpecker Prionochilus percussus | Yellow-breasted flowerpecker Prionochilus maculatus 4 Orange-bellied flowerpecker Dicaeum trigonostigma 1 Understory flycatching species Scarlet-rumped trogon Harpactes duvaucelii 4 | Δ Red-bearded bee-eater Nyctyornis amictus 1 Greater racket-tailed drongo Dicrurus paradiseus 10 12 1 | Δ Grey-chested jungle-flycatcher Rhinomyias umbratilis 12 13 1 | Black-naped monarch Hypothymis azurea | Asian paradise-flycatcher Terpsiphone paradise 0 Rufous-winged philentoma Philentoma pyrhopterum 11 12 1 | Δ Sunda blue flycatcher Cyornis caerulatus 0 142Notes: † - This column indicates whether the species was included in the guild-level analyses The numbers before and after 143the bar ‘|’ indicate the numbers of individuals from each site that were included in the analyses of approaching propensity and 144behavioral conspicuousness, respectively The triangle ‘Δ’ indicates the species that were included in the analysis of body mass 24 12 25 145as described in Appendix ‡ - The only incidence of the crested jay did not approach within 15m from the playback center, 146hence was not counted toward the species and individuals that responded to the mobbing playback 147 148 149 26 13 27 150 Appendix Model performance 151Table A6.1 AICc ranking of candidate models for comparison of mobbing intensity across forest sites Mobbing intensity Foraging guild Gleaning birds measure Conspicuousness Propensity Sallying birds 28 Conspicuousness Fixed effect variables K AICc ΔAICc None Group size Time Forest site Group size + Time Forest site + Group size Forest site + Time Forest site + group size + Time Forest site Forest site + Time Forest site + Group size None Forest site + Time + Group size Group size Time Group size + Time Group size + Time Group size Forest site + Group size + Time Forest site + Group size None Time Forest site + Time Forest site 5 56 8 8 5 6 5 159.89 160.16 162.03 162.32 162.35 164.01 164.55 166.25 271.39 273.26 273.40 275.13 275.25 276.92 277.19 279.00 121.15 121.95 125.35 127.63 129.33 129.72 132.81 134.98 0.27 2.14 2.43 2.46 4.12 4.65 6.36 0.00 1.87 2.02 3.74 3.86 5.53 5.81 7.62 0.79 4.20 6.48 8.18 8.57 11.66 13.82 14 AICc Cumulative AICc weight 0.33 0.28 0.11 0.10 0.10 0.04 0.03 0.01 0.46 0.18 0.17 0.07 0.07 0.03 0.02 0.01 0.54 0.36 0.07 0.02 0.01 0.01 0.00 0.00 weight 0.33 0.61 0.72 0.82 0.91 0.95 0.99 1.00 0.46 0.63 0.80 0.87 0.94 0.96 0.99 1.00 0.54 0.90 0.96 0.98 0.99 1.00 1.00 1.00 29 Propensity 30 None Group size Time Group size + Time Forest site Forest site + Group size Forest site + Time Forest site + Group size + Time 15 2 5 47.95 50.17 50.19 52.56 54.10 56.64 56.81 59.54 2.23 2.24 4.61 6.16 8.70 8.86 11.59 0.55 0.18 0.18 0.05 0.03 0.01 0.01 0.00 0.55 0.73 0.91 0.96 0.98 0.99 1.00 1.00 31 152Table A6.2 AICc ranking of candidate models for analysis of the relationship between mobbing intensity and vegetation 153 structure Foraging Mobbing guild intensity measure Gleaning Conspicuousness AICc Cumulative 0.00 weight 0.18 AICc weight 0.18 0.64 0.92 1.13 1.70 1.91 1.97 2.58 2.82 3.16 3.22 3.76 3.84 4.16 4.79 6.00 0.00 1.77 2.01 2.07 3.85 3.87 0.13 0.11 0.10 0.08 0.07 0.07 0.05 0.04 0.04 0.04 0.03 0.03 0.02 0.02 0.01 0.37 0.15 0.13 0.13 0.05 0.05 0.31 0.42 0.52 0.60 0.67 0.73 0.78 0.83 0.86 0.90 0.93 0.95 0.97 0.99 1.00 0.37 0.52 0.65 0.78 0.83 0.89 Fixed effect variables K AICc ΔAICc Canopy + Understory 158.19 Canopy Canopy + Group size Canopy + Understory + Group size None Canopy + Understory + Time Group size Understory Canopy + Time Canopy + Group size + Time Canopy + Understory + Group size + Time Understory + Group size Time Group size + Time Understory + Time Understory + Group size + Time Understory Understory + Time Canopy + Understory Understory + Group size Canopy + Understory + Time Understory + Group size + Time 4 2 3 3 4 158.82 159.11 159.32 159.89 160.10 160.16 160.77 161.01 161.35 161.41 161.95 birds Propensity 32 16 162.98 164.19 269.05 270.82 271.06 271.12 272.90 272.92 33 Sallying Conspicuousness Canopy + Understory + Group size Canopy + understory + Group size + Time None Canopy Group size Time Canopy + Group size Canopy + Time Group size + Time Canopy + Group size + Time Canopy + Group size + Time 2 3 4 273.16 275.01 275.13 276.91 276.92 277.19 278.84 279.00 279.00 280.95 118.96 4.11 5.96 6.08 7.86 7.87 8.14 9.79 9.95 9.96 11.90 0.00 0.05 0.02 0.02 0.01 0.01 0.01 0.00 0.00 0.00 0.00 0.38 0.93 0.95 0.97 0.98 0.99 0.99 0.99 1.00 1.00 1.00 0.38 Group size + Time Canopy + Understory + Group size + Time Canopy + Group size Group size Understory + Group size + Time Understory + Group size Canopy + Understory + Group size Canopy + Time Canopy None Time Canopy + Understory + Time Canopy + Understory Understory + Time Understory None Understory Canopy 4 2 3 2 121.15 121.23 121.37 121.95 122.06 123.16 123.45 127.58 128.35 129.33 129.72 130.07 130.90 131.12 131.27 47.95 49.60 49.68 2.19 2.28 2.41 2.99 3.10 4.21 4.50 8.62 9.39 10.37 10.76 11.12 11.94 12.17 12.31 0.00 1.66 1.74 0.13 0.12 0.11 0.08 0.08 0.05 0.04 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.29 0.12 0.12 0.50 0.62 0.73 0.82 0.90 0.94 0.98 0.99 0.99 0.99 1.00 1.00 1.00 1.00 1.00 0.29 0.41 0.53 birds Propensity 34 17 35 Group size Time Canopy + Understory Understory + Group size Understory + Time Canopy + Time Canopy + Group size Group size + Time Canopy + Understory + Time Canopy + Understory + Group size Understory + Group size + Time Canopy + Group size + Time Canopy + Understory + Group size + Time 154 36 18 2 3 3 3 4 4 50.17 50.19 51.49 51.89 51.95 52.07 52.07 52.56 53.93 53.98 54.37 54.61 56.58 2.23 2.24 3.55 3.94 4.00 4.12 4.12 4.61 5.99 6.04 6.42 6.66 8.63 0.09 0.09 0.05 0.04 0.04 0.04 0.04 0.03 0.01 0.01 0.01 0.01 0.00 0.62 0.72 0.77 0.81 0.84 0.88 0.92 0.95 0.96 0.97 0.99 1.00 1.00 ... 150 Appendix Model performance 151Table A6.1 AICc ranking of candidate models for comparison of mobbing intensity across forest sites Mobbing intensity Foraging guild Gleaning birds measure Conspicuousness... understory forest birds in south temperate rainforest - Auk 113: 944-949 67Sieving, K E., Willson, M F., de Santo, T L 2000 Defining corridor functions for 68 endemic birds of south-temperate rainforest... recording was taken during a naturally occurring mobbing 40event in the lowland rainforest of northern Sumatra (Lamno, Aceh Province) and 41graciously provided by B van Balen The cause of the mobbing