Edinburgh Research Explorer Repeatability of nest morphology in African weaver birds Citation for published version: Walsh, PT, Hansell, M, Borello, WD & Healy, SD 2010, 'Repeatability of nest morphology in African weaver birds', Biology letters, vol. 6, no. 2, pp. 149-151. https://doi.org/10.1098/rsbl.2009.0664 Digital Object Identifier (DOI): 10.1098/rsbl.2009.0664 Link: Link to publication record in Edinburgh Research Explorer Document Version: Publisher's PDF, also known as Version of record Published In: Biology letters General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 01. Oct. 2021 ARTICLE IN PRESS Biol. Lett. (2009) 0, 1–3 variation in a trait (e.g. Lessells & Boag 1987 ; Boake doi:10.1098 /rsbl.2009.0664 1989). As such, it has been used to demonstrate sig- 1 Published online 00 Month 0000 nificant potential for genetic control over nest 65 2 Animal behaviour building in sticklebacks, penduline tits and barn swal- 66 3 lows ( Schleicher et al . 1996 ; Moller 2005; Rushbrook 67 4 et al . 2008 ). The other side of the construction coin 68 5 Repeatability of nest is the contribution made by previous experience, 69 6 including that associated with learning and memory 70 7 morphology in African (Healy et al . 2008 ). Little is known about the impor- 71 8 tance of experience, but it is from weaver birds that 72 9 weaverbirds there is most evidence for a role for experience in chan- 73 10 74 Q1 Patrick T. Walsh 1,2, *, Mike Hansell 3, Wendy ging nest structure: the nests of first-year males are 11 75 D. Borello 4 and Susan D. Healy 1,2 untidy and loosely woven compared with those of 12 76 1 2 mature males ( Collias & Collias 1964 ). It is unclear, 13 School of Biology and School of Psychology, University of Saint 77 Andrews, Saint Andrews, UK however, to what extent the variability of weaver bird 14 3Division of Environmental and Evolutionary Biology, University of nests may be genetic in origin. 78 15 Glasgow, Glasgow, UK In order to determine the repeatability of nest mor- 79 4 16 Q2 PO Box 603, Gaborone, Botswana phology (width, length and height) in solitary weaver 80 *Author for correspondence ([email protected] ). 17 birds, we collected series of nests built by male 81 18 It is generally assumed that birds build nests Southern Masked weavers Ploceus velatus in Botswana 82 19 according to a genetic ‘template’, little influ- and by the larger bodied male Village weavers Ploceus 83 20 enced by learning or memory. One way to cucullatus in Nigeria. 84 21 confirm the role of genetics in nest building is 85 22 to assess the repeatability of nest morphology 86 with repeated nest attempts. Solitary weaver 23 87 birds, which build multiple nests in a single 2. MATERIAL AND METHODS 24 breeding season, are a useful group with which Completed nests were collected (November–December 2008) from 88 25 colour-ringed Southern Masked weavers in south-eastern Botswana 89 to do this. Here we show that repeatability of (Atholl Holme 11-KO, Gaborone) approximately 30 days after 26 nest morphology was low, but significant, in they were built. By this time the chicks had fledged. In total, 66 90 27 male Southern Masked weaver birds and not sig- nests were collected: three to eight (mean + s.e.m.: 4.71 + 0.40) 91 28 nificant in the Village weavers. The larger bodied nests each for 14 different males. We used wing length (11 of the 92 14 males) as a proxy of male body size ( Gosler et al . 1998 ). 29 Village weavers built larger nests than did 93 We also collected 27 nests (June–July 2008) from Village weavers 30 Southern Masked weavers, but body size did not in central Nigeria (Laminga Village, Jos, Nigeria), after males com- 94 31 explain variation in Southern Masked weaver pleted building the nest: three to six (4.33 + 0.42) nests each for 95 32 nest dimensions. Nests built by the same male six males. No body size measurements were available for the Village 96 weavers. 33 in both species got shorter and lighter as more 97 nests were constructed. While these data demon- For both species, the order in which the nests were built was 34 strate the potential for a genetic component of determined by periodic observation of males’ territories, daily in 98 35 variation in nest building in solitary weavers, it the case of the Southern Masked weavers and three times a week 99 36 for Village weavers. However, as some nests were destroyed before 100 is also clear that there remains plenty of scope collection, the nest data are analysed in sequential, rather than 37 in both of these species for experience to shape numerical, order. 101 38 nest construction. To measure each nest, digital images were captured using a 10 102 39 mega-pixel digital camera and analysed using image analysing soft- 103 Keywords: experience; nest building; repeatability; ware (Measuring Vegetation Health). Photographs were taken from 40 104 weaver bird a camera on a fixed tripod, with each nest placed 1 m away in 41 front of A3 (420 Â 297 mm) 1 cm grid graph paper to provide a 105 42 scale for the images. Each nest was photographed from two different 106 43 views: (i) a lateral side (the same side for all nests) provided nest 107 length and height (figure 1 ) and (ii) the posterior side, which 44 1. INTRODUCTION provided the nest width. Each nest was measured four times with 108 45 Nest building in birds is a widespread, commonly the mean value used in the analyses. Nests were weighed using an 109 46 observed behaviour, and yet we understand rather electronic balance (+0.1 g). 110 The date of nest construction and the sequential order in which 47 little about how birds construct what appear to be 111 the nests were constructed were highly correlated ( r ¼ 0.62, p , 48 species-specific nests. Simple, stereotyped building 0.0001), so Pratt’s measure of relative importance (PRI; Pratt 1987 ) 112 49 rules seem to explain even seemingly complex con- was used to determine that nest order (PRI ¼ 1.156) was substantially 113 ¼ 2 50 structions in invertebrates ( Hansell 2005), but how more important than was date of construction (PRI 0.156). 114 Therefore, analyses of nest size included sequential nest order rather 51 relevant such rules are to avian nest construction is than date of construction. The repeatability of nest size within males 115 52 unclear. While it is generally assumed that nest build- and species was analysed using the three nest size variables in a 116 53 ing in birds is largely innate (e.g. Hansell 2000; Moller multivariate ANOSIM (ANalysis Of SIMilarity), with 10 000 permu- 117 tations, in the PAST statistical package ( Harper 1999 ). Variation 54 2005; Raby & Clayton 2009 ), there are some species 118 among males was determined using linear mixed models, in SPSS 55 that build nests that seem beyond such simple rule- v. 17, with nests as a repeated measure and male as a random 119 56 governed, innate construction. Striking examples factor. Analyses were performed on log-transformed data. 120 57 come from the weaverbirds (Family Ploceidae), 121 58 which weave and knot plant material in a way that 122 59 has been likened to weaving in humans ( Collias & 3. RESULTS 123 60 Q3 Collias 1964). The length (L) and width ( W ) ( L: F13,51 ¼ 2.32, p , 124 61 A key to understanding how nest construction is 0.05; W: F13,51 ¼ 3.26, p , 0.005; figure 2a) of nests 125 62 achieved is to determine the degree of repeatability of constructed by Southern Masked weavers varied 126 63 nest morphology, as repeatability sets an upper limit across males, but nest height ( H ) did not ( F13,51 ¼ 127 64 on the heritability of a trait, i.e. the potential genetic 1.410, p ¼ 0.19). The dimensions of nests built by 128 Received 13 August 2009 Accepted 28 September 2009 1 This journal is q 2009 The Royal Society rsbl20090664—7/10/09—11:22–Copy Edited by: Chitra S ARTICLE IN PRESS 2 P. T. Walsh et al. Repeatability of nest morphology 129 weaver nests. Village weavers, the larger of the two 193 130 species (Hockey et al . 2005 ), built nests that are 194 131 larger in all three dimensions (length, width and 195 132 height) and heavier than those built by Southern 196 133 Masked weavers. In both species, nest length 197 134 decreased across the season, a decrease that was, in 198 135 Southern Masked weavers, independent of the total 199 136 number of nests built and of body size. 200 137 The repeatability of nest dimensions in Southern 201 138 Masked weavers confirms that there is potential for a 202 139 genetic component to nest building in these birds, as 203 140 seen with nest size (measured from top to bottom) in 204 141 penduline tits (Schleicher et al .