Bull 469 BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Kawalkar and Manchi Bull. Iraq nat. Hist. Mus. (2023) 17 (3): 469-480. https://doi.org/10.26842/binhm.7.2023.17.3.0469 ORIGINAL ARTICLE FIRST CONFIRMED BREEDING RECORD OF THE BLYTH’S SWIFT APUS PACIFICUS LEUCONYX (BLYTH, 1845) (APODIFORMES, APODIDAE) IN SOUTHERN PARTS OF NILGIRI REGION OF WESTERN GHATS OF INDIA Dhanusha Kawalkar and Shirish S. Manchi* Division of Conservation Ecology, Sálim Ali Centre for Ornithology and Natural History, Anaikatty (Post Office), Coimbatore – 641108, India. * Corresponding author: ediblenest@gmail.com Recived Date: 08 August 2022, Accepted Date 24 March 2023, Published Date:20 June 2023 This work is licensed under a Creative Commons Attribution 4.0 International License ABSTRACT Blyth’s Swift, endemic to the Indian subcontinent, is one of the four taxa of the Pacific Swift Apus pacificus complex. It is known to breed in high altitudes (>2,000 m) and disperse widely in winters, as far as the southern extremity of Nilgiri Region of the Western Ghats of India. However, the true extent of its non-breeding range remains uncertain. The present study reports the extended breeding range of the species and also an attempt to confirm its breeding range using the Species Distribution Modeling (SDM). In April 2020 in Anaikatty Hills of Southern Western Ghats, Coimbatore, we recorded an assemblage of four aerial foraging Aves; Indian Swiftlet Aerodramus unicolor (Jerdon, 1840), Asian Palm Swift Cypsiurus balasiensis (J.E. Gray, 1829), Red-rumped Swallow Cecropis daurica (Laxmann, 1769), and a large-sized swift. After referring to the experts’ field guides and discussions, we confirmed the species’ identification as the Blyth’s Swift Apus pacificus leuconyx (Blyth, 1845). The observed individuals of the Blyth’s Swift were carrying food bolus, confirming active breeding of the species in the Nilgiri region of the Southern Western Ghats of India. Also, the available breeding records were projected using Species Distribution Model SDM, the breeding range included the extent of Southern Western Ghats. We claim the first confirmed breeding record of the Blyth’s Swift in the region and an extension of the species breeding range. Keywords: Anaikatty Hills, A. p. leuconyx, Breeding range, Blyth’s Swift, Western Ghats INTRODUCTION The swift clan ‘Apodidae’ is divided into two subfamilies, Cypseloidinae and Apodinae (Chantler, 1999; Brooke, 1970, 1972). Furthermore, the Apodinae is subdivided into three tribes Apodini, Collocaliini, and Chaeturini, but out of all the position of Hirundapus in the Chaeturini clade faces a few minor challenges (Price et al., 2004, 2005). However, within “typical swifts” of Apodini, the systematics and taxonomy of the two Old World genera Apus and Tachymarptis have been under long-term contention, and higher-level phylogeny within BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Iraq Natural History Research Center & Museum, University of Baghdad https://jnhm.uobaghdad.edu.iq/index.php/BINHM/Home Copyright © Bulletin of the Iraq Natural History Museum Online ISSN: 2311-9799-Print ISSN: 1017-8678 https://doi.org/10.26842/binhm.7.2023.17.3.0469 https://orcid.org/0000-0002-6478-7522 https://orcid.org/0000-0002-7540-2616 mailto:ediblenest@gmail.com https://creativecommons.org/licenses/by/4.0/ https://jnhm.uobaghdad.edu.iq/index.php/BINHM/Home 470 BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM First confirmed breeding record Apodidae is yet to be fully resolved; furthermore, the absence of Apus swifts’ taxonomic controversy might be because comprehensive analyses of both comparative morphology and molecular data are still missing (Päckert et al., 2012). According to Leader (2011), the Apus pacificus complex is further sub-classified into four species; Pacific Swift A. p. pacificus, Salim Ali’s Swift A. p. salimalii, Cook’s Swift A. p. cooki, and Blyth’s Swift A. p. leuconyx. Blyth’s Swift is endemic to the Indian subcontinent (Leader 2011; Kirwan et al., 2020). Pacific Swift breeds in Siberia east to Kamchatka and northern Japan; winters in Indonesia, Melanesia, Australia, and possibly northeast India (Kirwan et al., 2020). Few studies (e.g., Davidson, 1898; Praveen et al., 2016; Cheke, 2018) predicted the possible breeding of Pacific Swift in the Nilgiris, Southern Western Ghats. Salim Ali’s Swift breeds on the Tibetan plateau and in western China, whose wintering grounds are unknown. Cook’s Swift is confined to South-East Asia and breeds from Myanmar east to Vietnam and south to Thailand (Kirwan et al., 2020). Blyth’s Swift is relatively large. The species is known to breed in the high altitudes of the Himalayas (>2,000 m) from March to May in Nepal and North-east India (Kirwan et al., 2020; Grimmett et al., 2011) and occur at 1,300m to 3,800m in Pakistan and Bhutan (BirdLife International, 2019). It is known to disperse widely during winter and is observed in Nepal’s lower altitudes and as far south as the Southern Western Ghats of India (Kirwan et al., 2020). However, the true extent of its non-breeding range and its relative frequency in different areas are poorly known (Kirwan et al., 2020). Furthermore, Blyth’s Swift has been observed wintering in Kerala and Goa (Kumar, 2017), confirming its migratory range throughout the Western Ghats (Bhagat, 2017). Understanding the limitations of Apodid identification in the field, their distribution in the region is not much evident as in the country. Hence, contributing to revealing the breeding status and non-breeding range of the Blyth’s Swift, the present report is the first confirmed breeding record of the species in Southern Western Ghats of India. Also, we used the Species Distribution Modeling (SDM) to confirm the extended breeding range of the species using the available presence records during the breeding season. Further, we presume the possible occurrence of a resident population of the Blyth’s Swift in the Nilgiri region of Southern parts of the Western Ghats of India. MATERIALS AND METHODS Study area: Anaikatty Hills (Map 1; 11.1048° N, 76.7683° E), with an elevation of 757m, is a part of the Nilgiri Biosphere Reserve, Western Ghats, located in the Coimbatore district of Tamil Nadu, India. The Western Ghats Mountain chain is older than the Himalayas and represents an array of geomorphic features of immense importance with unique biophysical and ecological processes (UNESCO, 2012). The region is part of the Eastern foothills of the Western Ghats and is identified as the rain shadow area. The area has a secondary forest surrounded by dry deciduous forests. The region receives an annual rainfall of about 700mm, mainly contributed by the North-East monsoon. The temperature here varies from 17 ̊C to 36 ̊ C (Mukherjee and Bhupathy, 2007). 471 BULLETIN OF THE IRAQ NATURAL HISTORY MUSEUM Kawalkar and Manchi Observation and identification: The observations mentioned in the present study are from the open residential area in Anaikatty valley. On 29 and 30 April 2020, a mixed flock of three foraging Apodids, Indian Swiftlet Aerodramus unicolor, Asian Palm Swift, and three individuals of large unidentified swift species along with Red-rumped Swallow were observed for 30 minutes. Initially, these three individuals looked like Little Swift Apus affinis, one of the most common Apodids in the region because of the prominent white rump and dark dorsal plumage. As all the four species were foraging together, comparing the body size was not very difficult using the Binoculars (Nikon: Monarch 10x42mm). When these birds were feeding just between 10–30 meters above ground, the larger body size of all the three individuals of the unidentified species was confirmed as Blyth’s Swift based on Grimmett et al. (2011) and Rasmussen and Anderton (2012). For further identification conformation, we also cited Kirwan et al. (2020). Moreover, we further shared images of the unidentified Apus sp. individuals with experts for conformed identification (see Acknowledgments section). To further authenticate our findings of the Blyth’s Swift in the Anaikatty Hills we made a distribution model using MaxEnt (Maximum entropy) approach. We used the 785 presence data points between the months (March–May) when to species is known to breed in its distribution range. The data was taken from Global Biodiversity Information Facility repository (GBIF Secretariat, 2021). For developing Species Distribution Model (SDM) for current scenario, 19 bioclimatic variables downloaded from Worldclim database version 1.4 (Tab. 1) were used. Out of these 19, six variables were included in the model after testing for correlation between variables (Tab. 1). For evaluation of the model, 75% of the species presence sites were used as training data and the remaining 25% was for testing the statistical significance. The model was run using five replicates with 5000 iterations. Rest of the settings was set to default. Model validation was performed using subsampling strategy. The threshold value based on the Area Under Curve (AUC) of the Receiver Operating Curve (ROC) ranges from 0 to 1, the AUC score of 1 indicates perfect prediction, with zero omission. However, the values equal to 0.5 indicates random prediction, while AUC values 0.8< AUC<1 were treated as good; 0.7