no SHORT NOTES Forktail 31 (2015) Siebers, H. C. (1928) Eine neue Pycnonotus-Axt von Nord-Sumatra. Treubia J. A. EATON, A-3A-5 Casa Indah I, Persiaran Surian, Petaling Jaya, 10:395-397. Selangor, 47410, Malaysia. [email protected] Tobias, J. A., Seddon, N„ Spottiswoode, C. N„ Pilgrim, J. P., Fishpool, L. D. C. & Collar, N. J. (2010) Quantitative criteria for species delimitation. Ibis N.J. COLLAR, BirdLife International, The David Attenborough Building, 152: 724 746. Pembroke Street, Cambridge CB2 3QZ, UK, & Bird Group, Department Wirth, R. (2014) Krieg am Vogel. ZGAPMitt 30(2): 3-6. of Life Sciences, Natural History Museum, Tring, Herts HP23 6AP, UK. Growth of Chinese Sparrowhawk Accipiter soloensis nestlings CHANG-YONG CHOI, HYUN-YOUNG NAM & WOO-SHIN LEE Introduction at different times of day e.g. body mass changes resulting from Being able to estimate the age of individual nestlings is essential short-term fluctuations in food supply (Hardey et al. 2006). To for various raptor studies, monitoring and conservation. Since avoid premature fledging, most measurements on nestlings (53/58 the increase in body measurements of raptor nestlings follows measurements; 91%) were taken during the 15 days after hatching. a predictable pattern, it is often possible to estimate the age of Since sexual dimorphism is small, even in adults of this species nestlings by fitting measurements of a given parameterto a growth (Kemp & Crowe 1994, Choi etal. 2013), we did not identify the sex curve of known form (Starck & Ricklefs 1998, Hardey et al. 2006). of nestlings. Information on nestling growth and best-fitting models of growth As growth in nestling body parts was best explained by logistic has been collected for many raptor species and populations, and growth curves, the logistic curve was estimated following Starck & used for reliable ageing and sexing, as well as for ecological studies Ricklefs (1998): of raptors (e.g. Moss 1979, Bortolotti 1984, Bortolotti 1986, Negro ef al. 1994, Vinuela & Ferrer 1997, Arroyo etal. 2000). l/1/=A/[1+exp(-K(f-f))] The Chinese Sparrowhawk Accipiter soloensis occurs in a wide geographic range throughout East and South Asia as a long-distance where W - the growth variable, A = asymptote, K = the growth migrant (Ferguson-Lees & Christie 2001). However, little information rate constant, f = age of nestling, and t. = the inflection point of the on the growth of nestlings has been recorded because of its growth curve. relatively confined breeding range in Korea and China (Ferguson- We measured wing (maximum wing length) and tail of 14 birds Lees & Christie 2001, Choi et al. 2013). Only two previous studies (seven males and seven females) in first summer plumage (IS), reported simple and general changes in nestling growth (Kwon captured at stopover sites on spring migration in May 2007 and & Won 1975, Park etal. 1975), but they did not provide any growth 2008, to provide asymptotic values for growth models. Because model for ageing nestlings. Hence, a growth model forthis species the sparrowhawks do not moult their flight and tail feathers in is desirable to facilitate further studies that require estimation of their first year, these measurements may represent the mean size of nestling age. The objective of this study was to give an account of the approximately 60-day-old birds, when they first start their migration growth of young Chinese Sparrowhawks by describing their general south. We ignored the potential effects of abrasion on feather length appearance, measuring nestlings of known age, and selecting the and possible size changes of structural parts during their first winter. best-fitting growth model for the accipiter. SAS 8.1 software (SAS Inst. Inc., Cary, NC, USA) was used for statistical analyses, and the constants for the logistic growth curve Methods were calculated from a non-linear procedure (PROC NUN) in SAS. We searched for nests of Chinese Sparrowhawks in June and July from 2005 to 2008 at Gwangju (37.450°N 127.283°E), Gyeonggi Results province, Republic of Korea, and identified the breeding status of The growth curves and the model predictors of the parts measured nests we found. We visited the nests daily or used video surveillance are presented in Figures 1 & 2 and Table 1. The inflection point of systems comprising camcorders (Panasonic NV-MX5000), infrared the body mass curve, indicating the time of highest growth rate, CCTVcameras (lEVision, IVT-26IRS; Samsung, SIR-4150) and DVD/DVR Figure 1. Growth in (a) body mass, (b) bill length, (c) tarsus length, recorders (Samsung SV-DVR350; Gyungil Electronic Co., DR-554N) and (d) head length of 16 Chinese Sparrowhawk nestlings from five to identify hatching dates. nests. Solid lines indicate the logistic growth curves, and dashed lines We measured six parameters (body mass, wing, tail, bill, represent upper and lower 95% confidence levels. head and tarsus length) of 16 nestlings from five nests. General measurement procedures, as described in Baker (1993) and Hardey etal. (2006), were used. Body mass was weighed to the nearest 0.1 g using a portable electronic scale when nestlings weighed <100 g (HS-120,OhausCorp„ NJ, USA) and to the nearest 0.5 g using a spring scale when the weight exceeded 100 g (Medio-40310, Pesola AG, Baar, Switzerland). Wing length and tail length were measured to the nearest 0.1 mm using a thin metal ruler. We tried to measure maximum wing length, although it was not always possible especially when the nestlings were young and the feather sheaths remained. Tarsus length, head length and bill length (measured from bill-tip to the distal part of the cere) were recorded to the nearest 0.01 mm using a digital vernier caliper (Digimatic 500-181, Mitutoyo Corp., Kawasaki, Japan). All measurements were taken in the late afternoon between 0 5 10 15 20 25 0 5 10 15 20 25 16h00and 18h00 to avoid any potential bias caused by measurements Age (day after hatching) Age (day after hatching) 111 Forktail 31 (2015) SHORT NOTES Three-day-old nestlings did not demonstrate any alert behaviour to the approach of researchers, but begged for food. Wing feather sheaths emerged three days after hatching and six- to seven-day-old nestlings had distinctly visible wing feather sheaths and bluish-grey claws, and began defensive behaviour against intruders. The cere was greenish yellow (Plate 2). Nine-day-old nestlings maintained an upright sitting posture on the nest or stood up for a short time. These nestlings still had egg-teeth, and the colour of their claws changed to dark grey. Flight feathers protruded out of sheaths, like a paint brush, at this age and tail feather sheaths that emerged seven days after hatching were clearly visible (Plate 3). Eleven-day-old nestlings had yellow feet Plate 1. Nest 1 - new hatchlings and eggs of Chinese Sparrowhawk Accipiter soloensis, 14 July 2005 Age (day after hatching) Plate 2. Nest 1 - eight- (right two), seven- (left bottom), and six- (left Figure 2. Growth in (a) wing length and (b) tail length of 16 Chinese top) day-old nestlings, 21 July 2005. Sparrowhawk nestlingsfrom five nests.Tail and maximum wing length of 14sparrowhawks (seven males and females) in first summer plumage were used for the growth curve development to compensate for the lack of measurements between fledging (when approximately 20-25 days old) and first migration (when approximately 60 days old). Solid lines indicate logistic growth curves, and dashed lines represent upper and lower 95% confidence levels. occurred six days after hatching (Table 1). The highest growth rates of wing and tail, which were not fully grown before fledging, were recorded 15 and 20 days after hatching, respectively (Table 1). Newly hatched nestlings (n = 5) had a head length of 26.57 ± 0.89 mm, a bill length of 5.83 ± 0.36 mm, a tarsus length of 14.67 ± 0.82 mm, and a wing length of 13.7 ± 1.0 mm, although there were no remiges or rectrices. Mean body mass on the day of hatching was 14.5 ± 1.7 g, but was dependent on food delivery to new hatchlings, which start begging for food within an hour of hatching; hatchlings which were fed weighed 15.4gand 17.1 g, whilst unfed ones weighed Plate 3. Nest 1 - nine- (central two), eight- (right), and seven- (left) day- 13.1-13.5 g. Hatchlings have pink cere, legs and tongue, and white old nestlings, 23 July 2005. claws; an egg-tooth is present (Plate 1). Table 1. Main growth variables and logistic growth curve parameters with their standard errors (se) of nestling Chinese Sparrowhawks Accipiter soloensis. A = the asymptotic value (unit: g for body mass, mm for others), K = the logistic growth constant (day1), t.=the age (days) of the inflection point. OI H C Growth variables A (se) K (se) t, (se) r1 G N O Body mass 125.60(2.37) 0.3116(0.0140) 6.136(0.185) 0.983 Y G- Head length 46.07 (0.80) 0.1515(0.0107) -1.650(0.208) 0.972 N A H Bill length 12.53 (0.55) 0.1394(0.0164) 1.229 (0.593) 0.931 C Y B Tarsus length 45.38 (0.62) 0.2729 (0.0125) 3.090(0.146) 0.980 S E T Wing length 196.42 (1.27) 0.1721 (0.0041) 14.976(0.167) 0.995 A L P Tail length 133.48 (1.15) 0.2231 (0.0113) 19.846(0.344) 0.993 LL A 112 SHORT NOTES Forktail 31 (2015) and cere, and some retained the egg-tooth. At this age, the tip of central belly and tibia; they spent time on branches around their tail feathers protruded from sheaths. nest, but frequently returned to its shelter (Plate 6). Dark contour feathers were visible over white down feathers at scapulars, breast and flanks in 14-day-old nestlings, and the Discussion egg-tooth was normally absent. Claws and tongue were slate- Knowledge of growth curves is very useful for estimating the age black. As this age, nestlings could remain in a standing posture of a nestling from a single measurement taken in the field (Hardey on the nest, and were exposed to rain without the adult female's et al. 2006). In particular, the logistic equation most frequently protection (Plate 4). Seventeen-day-old nestlings had some visible provides the best fit for avian growth data, including raptors (Starck juvenile feathers on the sides of breast and flanks, and dark contour & Ricklefs 1998, Hardey et al. 2006). In this study, six growth curves feathers began to cover the upperparts whereas their heads were were produced from the measurements of six given parameters still covered by down (Plate 5). At 20-21 days young sparrowhawks (body mass, bill, head, tarsus, wing and tail length) with age, and were almost covered by contour feathers except for the forehead, the logistic curves as predictors of nestling age fitted the growth of young Chinese Sparrowhawks well. Sexing nestlings based only Plate 4. Nest 2 - one 15- (centre), two 14- (left and right), and one 13- on external measurements is probably impractical because of the (bottom) day-old nestlings, 19 July 2005. considerable extent of overlap in measurements between male and female Chinese Sparrowhawks, even in adults (Choi etal. 2013), and because this species has the lowest level of sexual size-dimorphism index among 45 accipiter species (Kemp & Crowe 1994). Nevertheless, this study is the first to provide quantitative information and descriptions on the growth of sparrowhawk nestlings. Our data suggest that all measured parts may be useful for estimating the age of sparrowhawk nestlings, by fitting them to the developed growth curves, for two weeks after hatching at least. As body parts rapidly grow towards their asymptotes, from this stage onwards, sparrowhawk nestlings may be aged using wing and tail lengths even after fledging. Body mass is a major and general determinant of growth rate in birds (Ricklefs 1968); compared with other structural measurements of nestling growth, however, body mass is also variable and can be affected by detrimental conditions such as food shortage (Starck & Ricklefs 1998, Hardey et al. 2006). For instance, one chick which had been fed was heavier than two unfed siblings on the day of hatching in this study. Considering the Plate 5. Nest 1 - three 16- and 17-day-old nestlings, 31 July 2015. high predictive power of wing length (r2= 0.995) and tail length (r?= 0.993) and the longer period over which they both grow, it is recommended that wing and tail lengths are the best estimators of nestling age in Chinese Sparrowhawk, although tail measurements are not feasible until the rectrices first appear. In conclusion, the age of sparrowhawk nestlings can be predicted based on the growth patterns of six morphometries, particularly wing length. We suggest that the growth model estimated from our results and appearance descriptions may benefit further studies on the poorly documented Chinese Sparrowhawk. Acknowledgements We thank Jeong-Hwa Seo and Su-Man Kim who helped us to search for active nests of the species. This study was supported by the Korea Research Foundation Grant (KRF-2006-312-C00420) funded by the Korean Government (MOEHRD). Plate 6. Nest 1 - three 20- and 21-day-old nestlings on a branch References supporting their nest, 4 August 2015. Arroyo, B. E., DeCornulier, T. & Bretagnolle, V. (2000) Sex and age determination of Short-eared Owl nestlings. Condor 102:216-219. Baker, K. (1993) Identification guide to European non-passerines. Thetford: British Trust for Ornithology (BTO guide 24). Bortolotti, G. R. (1984) Physical development of nestling Bald Eagles with emphasis on the timing of growth events. Wilson Bull. 96: 524-542. Bortolotti, G. R. (1986) Influence of sibling competition on nestling sex ratios of sexually dimorphic birds. Amer. Nat. 127:495-507. Choi C. Y„ Nam H. Y„ Park J. G„ Bing G. C„ Park C. & Cho S.Y. (2013) Morphometries and sexual dimorphism of Chinese Sparrowhawks {Accipiter soloensis). J. Raptor Res. 47: 385-391. Ferguson-Lees, J. & Christie, D. A. (2001) Raptors of the world. London: Christopher Helm. Hardey, J„ Crick, H„ Wernham, C„ Riley, H„ Etheridge, B. & Thompson D. (2006) Raptors: a field guide to survey and monitoring. Edinburgh: The Stationery Office. Forktail 31 (2015) SHORT NOTES 113 Kemp, A. & Crowe, T. (1994) A morphometric analysis of Accipiter species. Vinuela, J.&Ferrer, M. (1997) Regulation of growth in Red Kitesand Imperial Pp.651-655 in B.-U. Meyburg & R. D. Chancellor, eds. Raptor conservation Eagles. Wilson Bull. 109: 92-101. today. East Sussex: WWGBP & Pica Press. Kwon K. C. & Won P. O. (1975) Breeding biology of the Chinese Sparrow Hawk Chang-Yong CHOI, Department of Forest Sciences, Seoul National Accipiter soloensis. Misc. Rep. Yamashina Inst. Orn. 7: 501-522. University, Seoul 151-921, Republic of Korea. Current address: Center Moss, D. (1979) Growth of nestling sparrowhawks (Accipiter nisus). J. Zool. for Spatial Analysis, University of Oklahoma, Norman, OK 73019, USA. 187: 297-314. Email: [email protected] Negro, J. J., Chastin, A. & Bird, D. M. (1994) Effects of short-term food deprivation on growth of hand-reared American Kestrels. Condor 96: Hyun-Young NAM, School of Biological Sciences, Seoul National 749-760. University, Seoul 151-721, Republic of Korea. Email: stern0223 Park Y. G., Yoon M. B. & Won P. O. (1975) Breeding biology of the Chinese @lycos.co.kr Sparrow Hawk Accipiter soloensis. Misc. Rep. Yamashina Inst. Orn. 7: 523-532. Woo-Shin LEE, Department of Forest Sciences, Seoul National Ricklefs, R. E. (1968) Patterns of growth in birds. Ibis 110:419-451. University, Seoul 151-921, Republic of Korea. Email: [email protected] Starck, J. M. & Ricklefs, R. E. (1998) Avian growth and development: evolution (corresponding author) within the altricial-precocialspectrum. Oxford: Oxford University Press. Species rank of Isabela Oriole Oriolus Isabellas and White-lored Oriole O. albiloris reinforced by song playback responses ANTHONY M. LOWNEY, MERLIJN VAN WEERD & SELVINO R. DE KORT Introduction currently classified as Critically Endangered it is imperative that The Isabela Oriole Oriolusisabellae and White-lored Oriole O. albiloris its taxonomic status is unambiguous. To that end, we conducted are endemic to Luzon, northern Philippines (BirdLife International playback experiments with both species to test whether they 2014). Historically, the Isabela Oriole was observed in two distinct discriminate between each other's songs. locations: the northern Sierra Madre mountain range in north-east Luzon and the Bataan Peninsula in western Luzon (Collar ef a/. 1999). Methods However, the species has been reported only three times since We used playback experiments to test the hypothesis that the 1961, namely (1) 15 km south of Diffun, Quirino province (Gamauf & Isabela and White-lored Orioles differentiate between conspecific Tebbich 1995); (2) Mansarong, Baggao, Cagayan province (van der and allospecific song. Females are expected to discriminate between Linde 1995)—neither of which were considered absolutely certain con- and allospecific stimuli if the consequences of hybridisation (Collar 1998)—and (3) Ambabok, San Mariano, Isabela province (van are maladaptive (Nelson & Soha 2004). However, females do not Weerd & Hutchinson 2004), all in north-east Luzon. There have been respond readily to playback in the field, which prevents testing no records from the Bataan Peninsula since 1947 (Collar etal. 1999). females (Catchpole & Slater 2008). Therefore, most studies that test The current population size of the Isabela Oriole is estimated at species recognition use territorial males as subjects (de Kort etal. fewer than 250 individuals and it is therefore classified as Critically 2002, Seddon& Tobias 2010). Playback of conspecific songs simulates Endangered (BirdLife International 2014). The White-lored Oriole is a territorial intrusion and usually leads to an aggressive response widely distributed throughout northern Luzon with a population from the territory owner (de Kort & ten Cate 2001, Slabbekoorn & estimated to be greater than 10,000 individuals and it is classified Smith 2002). Playback of territorial songs of allospecifics in general as of Least Concern (BirdLife International 2014). The two species tends to produce lower or no response by a territory owner, historically occurred sympatrically in the northern Sierra Madre and especially when two species are sympatric (Falls 1988, de Kort & the Bataan Peninsula (van Weerd & Hutchinson 2004, Collar 2011). ten Cate 2001, Catchpole & Slater 2008). Playback of bird songs is Little is known about the ecology of either species except that they therefore a useful method to test for biologically relevant species are canopy-dwellers and may be associated with secondary forest limits (Alstrom & Ranft 2003). and forest edge. If Isabela and White-lored Oriole males discriminate between Isabela and White-lored Orioles differ in plumage colour, bill conspecific and allospecific vocalisations, we infer that females length (Collar 1998) and vocalisations (van Weerd & Hutchinson will also respond differentially to the songs of the two species. This 2004). Isabela Oriole has a stout grey bill, mean length 28 mm, and would suggest that vocalisations can act as a mating barrier and yellowish lores, while the White-lored Oriole has a slender red bill, provide support for the current classification of the two orioles as mean length 21.8 mm, and broad white lores (Collar 1998). There distinct species. is little sexual dimorphism in either species (Kennedy etal. 2000). The songs of the White-lored Oriole are longer and more tonal or Study sites 'flutier' than those of the Isabela Oriole (van Weerd & Hutchinson Data were collected in three geographically separated areas: the 2004). Despite these differences the two species show limited Sierra Madre, Bataan Peninsula and Northern Cordillera (Figure 1). DNA sequence divergence, leading to the suggestion that they The two species occur sympatrically in lowland dipterocarp should 'perhaps' be considered 'a single taxonomic unit' (Jonsson forest in the San Mariano municipality, Isabela province (17°N et al. 2010). Collar (2011) disagreed with this and argued that the 122.167°E), in the northern Sierra Madre. San Mariano is situated morphological differences, in combination with the historical on the western edge of the Northern Sierra Madre Natural Park. sympatric occurrence in at least two locations, are sufficient to The Subic Forest Watershed Reserve (14.750°N 120.333°E) and consider the Isabela and White-lored Oriole as distinct species, Bataan Natural Park (14.700°N 120.367°E), both in Bataan province, which is also in concordance with a recently proposed method for are located within the Bataan Peninsula. White-lored Oriole is delimiting species (Tobias etal. 2010). Clearly, with the Isabela Oriole frequently observed in the Bataan Peninsula, but the Isabela Oriole