Nest tree preference shown by Ring-necked Parakeet Psittacula krameri (Scopoli, 1769) in northern districts of

: This paper pertains to the nesting aspects of Psittacula krameri with specific reference to nesting-related habitats, number of individuals encountered, inter-specific interactions, and abnormalities in 71 villages covering seven northern districts of Tamil Nadu. A total of 797 nests (500 active and 297 non-active nests) and 1,119 individuals were enumerated on 284 trees and 13 temples/buildings belonging to eight species, seven genera, and five families. The highest number of nests (320) and birds (469) occurred on Borassus flabellifer L., followed by Cocos nucifera L., Albizia lebbeck (L.) Benth., Madhuca longifolia J.F.Gmel., Phoenix sylvestris (L.) Roxb., and Ficus benghalensis L. This species prefers dead trees than living trees for nesting. The study reveals that 63.4% nests (n= 505) and 65.1% birds (n= 729) were found on dead trees of B . flabellifer , C . nucifera , and P . sylvestris . They generally prefer to build nests on trees situated near agricultural lands, followed by those near water bodies, human settlements, and temples/buildings. Pearson’s chi-square test indicates that the birds showed preference towards certain nesting sites/nesting species. Inter-specific interactions occurred between P . krameri and Blue Rock Pigeon, Spotted Owlet, Indian Roller, and Black-rumped Flameback for sharing of cavities/holes for construction of nests. Abnormalities in bird’s beak, cere, colour of feathers, and a suspected psittacine beak & feather disease (PBFD) were observed.


INTRODUCTION
The Ring-necked Parakeet or Rose-ringed Parakeet Psittacula krameri (Scopoli, 1769) (Aves: Psittaciformes: Psittaculidae) is a native of the Indian subcontinent and Sub-Saharian Africa and now occurs in 35 countries (Menchetti et al. 2016) such as Britain, Belgium, the Netherlands, Germany, and Spain (Braun & Wink 2013). A subspecies P. krameri manilensis is distributed in southern India and Sri Lanka (BirdLife International 2018). Intensive trade, accidental or deliberate release of this species into new environments and its adaptation has led to the establishment of viable populations outside its native range (Strubbe & Matthygen 2009;Neo 2012). Tolerance to human presence, an omnivorous diet and a great reproductive rate (Thabethe et al. 2013) make them successful invasive alien species and are even considered pests in the introduced European countries (Strubbe & Matthygen 2007). Many bird species use cavities as nesting sites, as it reduces the risk of predation more than other nest sites (Nice 1957;Cody 1985;Newton 1994). Psittacula krameri depends on trunk holes/ cavities for their reproduction. They compete with other birds for nest-cavities due to their aggressive behaviour in Mauritius (Jones 1980) and Belgium (Strubbe & Matthyen 2009). In India, they widely inhabit several habitats (Rasmussen & Anderton 2005) and breeding occurs during December-May. In northern India, about 15% of P. krameri populations build their nests in wall holes or crevices in buildings (Grandi et al. 2016). In view of the limited resources of nest-cavities, inter-specific competitions exist between P. krameri and other birds (Wesolowski 2007;Cornelius 2008).
The IUCN Red List of Threatened Species has evaluated the status of this bird as 'Least Concern' because its population appears to be increasing but in view of its popularity as a pet and control by farmers due to its invasiveness, this has reduced its numbers in its native range (BirdLife International 2018). Except the above few works, no literatures are available on the study of the nesting habitats and abnormalities of P. krameri in Tamil Nadu. Hence, this study was carried out to fill the gaps. The objectives of this study are to assess the nesting tree preference of P. krameri, and identification of the nesting sites.

Study area
The present study was carried out in 71 villages in seven districts of northern Tamil Nadu,viz.,Chennai,Thiruvallur,Ranipet,Kancheepuram,Chengelpet,Villupuram,and Kallakurichi spread over 17,680km 2 (Fig. 1). Agriculture is the primary occupation in these areas except Chennai City and adjoining areas. The major crops in the study area are Oryza sativa L., Sorghum bicolor (L.) Moench, Pennisetum glaucumi (L.) R.Br., Eleusine coracana Gaertn., Setaria italica (L.) P.Beauvois., Saccharum officinarum L. (Poaceae), Vigna radiata (L.) R.Wilczek., and Arachis hypogaea L. (Fabaceae). Smallscale cultivation of ornamental flowers, vegetables, and fruits also occurs. The maximum and minimum temperatures of these districts are 37 o C and 28 o C, respectively. The average annual rainfall of the state is 907mm (Tamil Nadu 2020).

METHODS
Three informants from villages who were traditionally engaged in farming and well acquainted with the location of tall trees, groves, and birds in the study districts were selected. Along with them areas were identified that had considerable populations of P. krameri and their nesting sites in 71 villages covering seven districts in the northern region of Tamil Nadu. The determined nesting sites were surveyed during the breeding season from 01 November 2019 to 31 March 2020 between 06.00 & 09.00 h and 15.00 & 18.00 h when the birds are usually active. The individuals and number of nests were determined using total count method (Bibby et al. 2000). P. krameri usually follow communal roosting during non-breeding periods and in the breeding season the flock splits and moves to various habitats searching for cavities to construct nests. Hence, the movements J TT of birds, the nesting trees, excavating cavities on the trunks, holes and crevices in temples/buildings, entry and exit of birds from such cavities, number of nests, active/ non-active nests, and inter-specific interactions with other birds for sharing nesting sites were observed using binoculars without causing any disturbance to the birds. The active nest cavities were ascertained by watching the frequent visits of birds to the cavities, carrying nesting materials: prolonged presence of any one of the pair in the cavity was presumed as the birds incubating eggs, and prey delivery to hatchlings. Non-active/abandoned cavities were ascertained by non-visiting of birds to the cavities during the study period after excavating cavities. The eggs and other breeding activities were not studied. Locations of the nesting trees and temples/buildings were determined using GPS. Pearson's chi-square test was applied to determine whether Ring-necked Parakeet individuals select trees, temples/buildings equally across the study area for construction of nests using SPSS (Statistical Package for Social Sciences) version 25.0 software. The test of significance was assessed at p< 0.05. Photographs and videos were taken using Nikon P1000 digital camera.

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Village and in four villages no nests were counted but individuals of P. krameri were enumerated. The details of villages containing nests and birds are given in Table 2.
Of the total B. flabellifer trees (164) enumerated in the study area, 158 were dead and six were living trees. Among B. flabeliifer, maximum of 98.1% nests (n= 314) and 96.2% birds (n= 451) were found on dead trees and only 1.9% nests (n= 6), and 3.8% birds (n= 18) were enumerated on living B. flabellifer trees.
Chi-square test was used to determine whether any significance existed between the type of nesting sites such as trees, temples/ buildings and the number of birds, nests, active nests and non-active nests. The test revealed that there exists statistically significant association between nesting sites (trees/temples/ buildings) and the number of birds (p< 0.05), nests (p< 0.05), active nests (p< 0.000) and non-active nests (p< 0.05) in the study area.

Preference of habitats for nesting
The study also tested the relationship between the selection of nesting sites and surrounding habitats such as agricultural lands, water bodies, human settlements, and temples/buildings by P. krameri populations (Fig. 2). About 39.4% of nesting sites (n= 117), 29.1% nests (n= 234), and 33% birds (n= 369) occurred near agricultural lands. Thirty-five per cent of nesting sites (n= 104), 22.8% nests (n= 182), and 24.3% birds (n= 272) occurred adjacent to water bodies such as bunds of lakes, ponds, rivers, or canals. About 22.2% nesting sites (n= 66), 28.3% nests (n= 226), and 28.1% birds (n= 314) were found near human settlement areas; 19.5% nests (n= 155), and 14.6% birds (n= 164) were counted on 13 temples/buildings (3.4%). The study also revealed that a maximum of active nests 35.2% (n= 176) were found on trees located in the agricultural areas, followed by 26.6% active nests (n= 133) near water bodies, 24.6% nests (n= 124) in the human settlement areas, and 12.6% nests (n= 63) on temples/ buildings (Image 1). Statistically a significant association exists between the type of habitats such as agricultural lands, water bodies, residential areas, temple & number of birds (p< 0.05), nests (p< 0.05), active nests (p< 0.05), and non-active nests (p< 0.05). Hence, all four types of habitats had an impact on the number of birds and nests in the study area.

Observation on abnormalities
In the present study, one male bird with beak deformity was observed on the compound wall of a temple in Thiruvalangadu Village (Thiruvallur District). The upper mandible of this bird was found elongated, curved and this colourless over grown part of the beak had elongated up to the neck. One female bird with swollen and distorted cere and a big nostril was observed in Gadavarikandigai Village (Ranipet District). Another bird with colour abnormality, i.e., yellow feathers on its back and four individuals (three females and one male) with loss of feathers and wart like skin on their heads were observed in Gadavarikandai Village. During the entire study period, they had the same symptoms without regeneration of new feathers on their heads (Image 3a-d).

Psittacula krameri individuals and their preference of nesting sites
In the present study, it was observed that P. krameri individuals selected a variety of trees for nesting, but they showed a preference towards palms (Arecaceae): B. flabellifer, C. nucifera and P. sylvestris. Among the palms, they prefered B. flabellifer (55.2%; n= 164) in the study area since 40.1% of nests (n= 320) and 41.9% birds (n= 469) occurred on them. The present observation of maximum number of nests and birds were found on B. flabellifer trees. The present study also reveals that they largely preferred dead palm trees for construction of nests. Except six B. flabellifer trees, all the palm trees (n= 158) that bore nests were dead trees. It suggests that the birds selected dead tree trunks for easy excavation of cavities using their powerful beaks. Once they select   Ali & Rilpey (1969) reported that in India, apart from the cavities of trees this bird also utilizes existing crevices in buildings for construction of nests. In Pakistan, this bird selected holes in trees as well as crevices in buildings for construction of nests (Jahan et al. 2018). Breeding of P. krameri in buildings is very common in Britain, Germany, Belgium, and Japan (Braun 2004(Braun , 2007. Some breeding pairs build nests in wall holes or crevices of buildings in north India and Spain. In Pavia (northern Italy), the entire population breeds in scaffold holes of the Visconti castle and towers (Grandi et al. 2016). The present study reveals J TT that 26% nests (n= 208) and 16.8% birds (n= 188) were counted on 10 temples and three buildings in the study area. The present observation of successful utilization of available holes/crevices in the temple and buildings for construction of nests by P. krameri population matches the findings of Ali & Rilpey (1969), Jahan et al. (2018), and Braun (2004, 2007.

Preference of habitats for nesting
As a social bird, P. krameri generally prefers to build nests on trees situated near agricultural lands. Occurrence of 29.1% nests (n= 234) and 33% birds (n= 369) on the trees situated near the agricultural lands prove that

Image 1. Nesting habitats of Psittacula krameria: a-a pair of birds roosting on temple wall | b-female individual in wall hole in temple | cmale individual in a cavity of dead B. flabellifer trunk | d-a pair engaged in excavation of cavity on B. flabellifer trunk | e-female individual in a trunk cavity, and | f-a mating pair. © M. Pandian.
the birds preferred to breed in agricultural areas where abundant food materials are available. Another 22.8% nests (n= 182) and 24.3% birds (n= 272) were found on trees located near water bodies. Maximum nests of P. krameri were found in the areas where cultivation of crops occurs and near water bodies in Punjab (Khan 2002a) and Hawaii (Paton et al. 1982). In the present study, occurrence of 51.9% nests (n= 416) and 57.3% birds (n= 641) in agricultural lands and close to water bodies in rural villages clearly indicates that the birds selected nesting sites in agrarian landscapes ensuring availability of abundant food material. Hence it matches with the observations of Khan (2002a) and Paton et al. (1982).

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This bird also preferred trees near human settlements and holes/crevices of temples/buildings for construction of nests. It suggests that the birds tolerate the presence of human.

Observation of inter-specific interactions
Cavity nesters pose a unique habitat problem. Obligate cavity nesters are associated with intra and inter-specific competition for nest sites (Collias & Collias 1984;Nilsson 1984). Jones (1980) had stated that incidents of competition between P. krameri and mynas Acridotheres tristis for sharing nest cavities in trees was reported in Mauritius. In view of the limited availability of nest-holes, inter-specific competition usually occurs between secondary cavity nesting birds in human altered landscapes (Cornelius 2008). They compete with native birds for sharing trunk-holes in Belgium also (Strubbe & Matthysen 2009). In the present study too P. krameri competed with a Blue Rock Pigeon, for sharing a hole in a temple, with a Spotted Owlet, an Indian Roller and a Black-rumped Flameback for sharing trunk holes in B. flabellifer trees during the breeding period. Hence, the present observation of inter-specific competition with other birds for sharing nesting sites corroborates with the findings of Jones (1980) and (Strubbe & Matthysen 2009).

Observation of abnormalities
Beak abnormalities may occur due to various causes such as malnutrition, infections, injury, mutations, defective bone growth, tear of rhamphotheca, and misalignment of maxilla & mandible (Oslen 2003;Handel et al. 2010;Zylberberg et al. 2018). Deformed beaks take many forms with upper/lower mandibles elongated, curved or mandibles crossed and are more prevalent in passerines (Craves 1994). Pomeroy (1962) has observed that abnormal bills in wild birds are rare with an estimated frequency of less than 0.5%. British Trust for Ornithology (BTO 2014) has recorded 36 species with beak deformities including ring-necked parakeets. In India, Kasambe et al. (2009) andSoni et al. (2019) have reported bill deformities in Yellow-billed Blue Magpie, Crow, and Common Myna. Kanwar (2019) has recorded beak abnormality in Ringnecked Parakeets in Chandigarh. In the present study, the upper mandible of one male bird was found colourless, curved and elongated up to its neck. This type of beak deformity may cause hardship to the bird while foraging and feeding chicks. Out of 1,119 birds studied, only one individual, i.e., 0.09% had a bill deformity. Hence, it confirms the view of Pomeroy (1962) that abnormal bills in wild birds are rare with an estimated frequency of less than 0.5% One female bird with swollen and distorted cere with a big nostril was observed. Cornification and keratinization of the cere can progress to close up the nostrils. These abnormalities in cere might have been caused by the mite, Knemidokoptes pilae (Zwart 1995). The study reveals that one female bird with similar symptoms of swollen and distorted cere with big opening was found. The observed symptoms matched the findings of Zwart (1995).
Colour mutations in P. krameri such as yellow (Bhargava & Hanfee 1996), white-rose (Mahabal et al. 2015), albinism (Mahabal et al. 2016), and cinnamon green (Kushwaha & Kumar 2018) have been reported in India. In U.K., many colour mutations have occurred in captive birds (Low 1992;Butler 2003). Hence, the present observation of yellow colour mutation of feathers in the study area corroborates the findings of the aforesaid authors. Pass & Perry (1984) and Ritchie et al. (1991) had stated that psittacine beak & feather disease (PBFD) caused by a virus has emerged as a major threat to the wild parakeet populations. The observed four P. krameri individuals with similar symptoms of feather loss and warty skin on their heads are suspected to have PBFD.

CONCLUSION
The present study was confined to a small geographical area covering 71 villages in seven northern districts of Tamil Nadu. Since a total of 1,119 individuals and 797 nests were enumerated in this region, it is considered a hotspot for breeding of this species. A systematic survey of the entire state would throw more light on the status and distribution of Ring-necked Parakeets in the state, and help in drafting an action plan to conserve their habitats in and around villages and also in the urban areas. www.threatenedtaxa.org The Journal of Threatened Taxa (JoTT) is dedicated to building evidence for conservation globally by publishing peer-reviewed articles online every month at a reasonably rapid rate at www.threatenedtaxa.org. All articles published in JoTT are registered under Creative Commons Attribution 4.0 International License unless otherwise mentioned. JoTT allows allows unrestricted use, reproduction, and distribution of articles in any medium by providing adequate credit to the author(s) and the source of publication.

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