Raptors observed (1983–2016) in National Chambal Gharial Sanctuary: semi-arid biogeographic region suggestions for parametric studies on ecological continuity in Khathiar-Gir Ecoregion, India

: The birds of prey or raptors in the National Chambal Sanctuary (NCS) assume importance as they are among the top predators of the region, predating on small crocodilians, turtles, and birds. Our checklist of 30 species of raptors is developed from observations made during winter surveys conducted between 1983 and 2016. The study area covered the course of river Chambal including its confluence with river Kuno that leads from Palpur-Kuno Sanctuary in Madhya Pradesh. The raptors which use the steep and inaccessible mud cliffs of the Chambal landscape include Bonelli’s Eagle Aquila fasciata , Laggar Falcon Falco jugger , Egyptian Vulture Neophron percnopterus , White-rumped Vulture Gyps bengalensis , Spotted Owlet Athene brama , and the Indian Eagle-Owl or Rock Eagle Owl Bubo bengalensis . Most of the other raptors noted in NCS appear to visit from and around the adjoining wildlife areas of Rajasthan and Madhya Pradesh. According to two methods of classification the study comes in the semi-arid biogeographic zone or Khathiar-Gir dry deciduous forest ecoregion. The list of raptors from NCS-Kuno has been compared with previous reports and the list available for Sariska Tiger Reserve and Ranthambhore Tiger Reserve in Rajasthan. The present work is the outcome of a long-term ecological monitoring that primarily focused on the Gharial Gavialis gangeticus and its ecological associates in water and the riverine shores. The birds of prey demanded time and attention for looking above and away from the water surface or the shorelines. Yet, our meticulous records maintained over 34 years have generated a basal profile that is expected to inspire focused studies on parameters that sustain ecological association of raptors of NCS adjoining forest habitats and wildlife sanctuaries in the ecoregion.


Background to the study
The UNDP/FAO/Government of India Project for Conservation of Crocodiles which was initiated in 1974-75 (Bustard 1999) concluded in 1982(de Vos 1984 with several significant contributions to a scenario in Indian wildlife conservation (Singh 1999). The next year, at the behest of the Government of India, LAKS from the erstwhile Central Crocodile Breeding and Management Training Institute (CCBMTI), Hyderabad, established and pursued teamed-up research goals in National Chambal Sanctuary (NCS), with headquarters at Deori Village Gharial Rearing Centre in Morena district, Madhya Pradesh. Since then, annual monitoring of Gharials and incidental collection of ecological and biological data of prominent wetland fauna has been carried out with simple protocols, for highlighting the results of wildlife management in NCS.
Much of the research work from NCS in this context is focused on Gharial, Mugger crocodile, Gangetic Dolphins, turtles, and non-raptor birds (Singh & Rao 1984, 1985Singh 1985;Singh & Sharma 1985Rao & Singh 1987a,b,c;Sharma & Singh 1986Sharma et al. 1995). Until superannuation in 2016, fieldwork continued with RKS, a key member of the NCS team. The records on the birds of prey during the river surveys were occasional as they demanded attention for looking above and away from the water surface or the shorelines. However, because of meticulous records maintained over a long time, attention was reverted to raptors which are among the biological predators of crocodiles and large birds.
The raptors or birds of prey, while predating upon fish and bird fledglings, also predate through creche of crocodilian hatchlings and small juveniles of Gharial and Mugger. Although cursory remarks on predation aspects have been made in our previous publications, a separate treatment for raptors was not attempted. Sharma & Singh (1986)

Raptors among crocodile predators
Elsewhere, Vyas (2019) provided a list of predators which affect nests or young ones of different crocodilian species. In this list, the species of birds that are known to predate on crocodilians are the Crow, Black or Pariah Kite, egrets, Purple Heron, Black-necked Stork, Painted Stork, Sarus Crane, and the White-bellied Sea Eagle. The presence of all species except the White-bellied Sea Eagle, is recorded for NCS (Sharma & Singh 1986). Gopi & Pandav (2006) and Palei et al. (2019) have reported or photographed the White-bellied Sea Eagle Haliaeetus leucogaster preying on Saltwater Crocodile Crocodylus porosus. The role of raptors in decimating populations of Mugger Crocodile Crocodylus palustris by 1975 (Singh 1979) in Similipal Tiger Reserve, Odisha cannot be ruled out, but Singh (1993) gave a list of 25 raptors seen here. The raptors are among the world's most graceful and spectacular birds for their characteristic display of wings in flight, their body colour, and the size and shape of the tail. The high visual acuity of eagles in bright daylight and the highly sensitive vision of owls with adaptations to dim-light vision has fascinated mankind (Potier et al. 2020). Being predators at the top, the birds of prey live in low numbers. The threats to tropical raptors include habitat destruction, environmental contamination, and persecution or shooting (Bildstein et al. 1998;Prakash et al. 2003;Green et al. 2004;Meteyer et al. 2004;Shultz et al. 2004;Swan et al. 2006a,b;Hernández & Margalida 2009;Zabala et al. 2020).
Out of 292 species of tropical raptors, 76% (222) are completely in the tropics; and most of the forest dwelling tropical raptors are secretive and difficult to study (Bildstein et al. 1998). The Chambal region supports a significant number of raptors and this is evident from numerous casual sightings and anecdotal references, as well as incidental observations. Based on our notes from the riverine landscape, and the taxonomic status given in the IOC World Bird List (Gill et al. 2021), the diurnal birds of prey that include hawks, eagles, and vultures are in the order Accipitriformes, and falcons in the order Falconiformes. Owls, which are nocturnal birds of prey are in order Strigiformes. A few of these species breed in the Chambal landscape. The steep and inaccessible mud cliffs appear to be preferred sites of Bonelli's Eagle, Laggar Falcon, Egyptian Vulture, White-rumped Vulture, Spotted Owlet, and Indian Eagle Owl.
In this note, we present a list of raptors that were incidentally sighted during our annual river surveys in the National Chambal Sanctuary and the Kuno confluence leading to Palpur-Kuno Sanctuary in Madhya Pradesh. Since the presence of some raptors does not get the support of breeding evidence along the Chambal, the raptor lists from Ranthambhore and Sariska have J TT been compared for possible insight into their presence resulting from local flights and extended home range. We expect our study may stimulate more conclusive knowledge on these aspects from systematic raptorspecific studies in the future in the Chambal landscape within the semi-arid biogeographic zone (Rodgers & Panwar 1988) and the Khathiar-Gir dry deciduous forest ecoregion (WWF 2021).

Study Area
Chambal in northwest India is a clear and fast-flowing river that originates from the Vindhya Range in central India. A stretch of about 572 km of the river Chambal, bordering the states of Madhya Pradesh, Rajasthan, and Uttar Pradesh, constitutes the National Chambal Sanctuary (NCS) (Figure 1). The NCS is protected for conservation and management of the endangered Gharial Gavialis gangeticus since 1979.
The biodiversity components of the river under NCS holds a number of indicator fauna which include the crocodilians, chelonians, and avian species. Besides, there are the Gangetic Dolphins and otters. Within the sanctuary limits, the river banks have ravines with sparse ground cover. The natural vegetation comprises of thorn forests, forming most of the boundary for Madhya Pradesh. The nearest forested habitat is in the Kuno-Palpur Wildlife Sanctuary in Madhya Pradesh ( Figure 2). However, close to NCS, there are a few forestbased well-known wildlife sanctuaries (WS) in Rajasthan. These include the Jawahar Sagar Wildlife Sanctuary and Ranthambhore Tiger Reserve in Rajasthan.
The habitat from Pali to Chakarnagar in Chambal ( Figure 2) comprises the most significant area for the conservation of Gharial. Keeping in mind the conservation significance of the critically endangered gharial and its habitat, the population trends and probable threats are among the parameters that have been assessed regularly with defined gaps. Every year, Madhya Pradesh Forest Department takes a systematic initiative to carry out a comprehensive survey to find out the status and distribution of Gharial and its ecological associates in NCS. Sometimes, survey cruises by boat and foot are also extended into the tributaries like, Parbati, Kali Sindh, Banas, and Kuno. The Kuno-Chambal confluence is downstream of Nadigaon village which is a nesting site of Gharial and Mugger (Singh 1985;. Upstream of Nadigaon, the Baroli sandbank, and Baroli island are considered among the best nesting sites of gharial and offer scope to observe all the sequences of breeding J TT behaviour by adults and creche formation by hatchlings. The hatchlings congregate around the confluence of the Kuno river, because of the availability of smaller fishes, and for retreat into the tributary during the flood. About 30 km upstream of the Kuno-confluence, the Palpur-Kuno WS was established in 1981 in the state of Madhya Pradesh with an initial area of about 344.68 km 2 . It is a dry deciduous forest forming a part of the Vindhyan hill range.

MATERIALS AND METHODS
The NCS was marked into twelve stretches of smaller study zones (Figure 2 based on Singh 1985) and the area was surveyed by travelling on a motor boat as well as by walking on foot. The surveyors were equipped with 1:50,000 toposheets from Survey of India, A4-size bits of field map sheets, binoculars, and a camera. The team along with the support staff normally moved between 0900 h and 1700 h. during the winter. When moving by motorboat, the transect speeds ranged within 15 km per hour, depending on the demands of the situation and navigability of the stream. Birds were sighted with the help of binoculars (Olympus 10 × 50 mm), occasionally aided with a spotting scope. Field notes were made directly on the field map sheets or notebooks. The bird species were identified using standard field guides, such as Ali (1979Ali ( , 2002, Naoroji (2011), and Grimmett et al. (2011). Observed species of raptors were recorded along with sighting time and nearest village name and other ancillary information on datasheets. A list of all the raptor species observed in the Chambal and Kuno region is given in

The Checklist of raptor birds in NCS-Kuno
a) The list of raptors based on our observations comprises a total of 30 species (Table 1 and Supplement  Table A). It includes six species of vultures, one osprey, two kites, one shikra, one harrier, three buzzards, five eagles, one kestrel, one hobby, two falcons, and seven owlet/owls. The family-wise list incorporates Falconidae four species, Accipitridae 18 species, Tytonidae one species, Strigidae six species, and Pandionidae one species.
b) In our list, a total of nine species falls under the d) Our preliminary observations indicate that the raptors received protection that is available as incidental to Gharial conservation in NCS. e) In Wildlife (Protection) Act, India the Schedule-IV status is given to Cinereous Vulture, Egyptian Vulture and Red-headed Vulture. This, however, does not match the grave status given to these species under the IUCN as NT, EN, and CR, respectively (Table B). We agree that the Egyptian Vulture or Pharaoh's Chicken appear to be in relatively good numbers but because of their size they might be more prone to killing. The suggestions made here on the possible lift or upgradation of Scheduled status of these three raptors merits the attention of the Ministry of Environment, Forests and Climate Change (MOEFCC) and requires further consultation with established ornithologists of India.

Species-wise total sightings
a) The total number of birds counted during the survey period 2003-2016 was 2070, with a range of 85-188, and an average of 148 birds per year ( Table 2). The moving average of the number of birds per year appears to indicate that NCS continues to be a good habitat for raptor sighting ( Figure 3). b) In the entire list (Table 1) there are seven species whose total count in 14 annual surveys has been less than five. These are, one bird per one survey for Cinereous Vulture (4 sightings), Griffon Vulture (4 sightings), Common Buzzard (4 sightings), White-eyed Buzzard (2 sightings), Crested Honey Buzzard (4 sightings), Pallas's Fish Eagle (1 sighting), and Dusky Eagle Owl (4 sightings). c) Pallas Fish Eagle was last seen in 1986 (Supplement Table A) and has not been recorded since then. There has been an increase in the number of sightings of Western Osprey over the years. Although the Western Osprey is considered to be a winter visitor, it is seen in Chambal in

J TT
fair numbers until late summer. d) Indian White-rumped Vultures were found in fair numbers in Chambal Sanctuary and large flocks could be seen until 1990, when a maximum of 304 vultures were recorded (Supplement Table A). Following this, there has been a steady decline. Only a total of four vultures were recorded in 2016 3. Survey-year-wise species sightings (Table 2) a) Ten species of raptors appear to have NCS in their preferred home range. Seven species were observed for 11 or more of the total 14 continuous annual surveys. These are the Egyptian Vulture (14 years), Whiterumped Vulture (all 14 years), Red-headed Vulture (13 years), Western Osprey (all 14 years), Shikra (14 years), Western Marsh Harrier (13 years), and Laggar Falcon (13 years). There were two species that were seen in 10 out of 14 surveys. These species are the Bonelli's Eagle and Common Kestrel (Table 1). b) During our survey years, 2003 to 2016, the number of species observed per year varied between 10 and 22 species (Table 2, Figure 4). In 1990, only three species of raptors were noted namely, the White-rumped Vulture with 304 counts, Indian Vulture four birds counted and 28 bird counts of Western Osprey (Supplement Table A). c) Very low sightings or no sighting of a species during any survey indicates the basic territorial characteristics of raptors, the possibility of their long home range, their seasonal and migratory habits, and our winter-season linear survey along the 572 km long Chambal River. Moreover, the survey objectives were targeted at the species seen in the water or on the river banks.
d) The index describing year-wise raptor counts and raptor species is an average of 9.9. This demonstrates a fairly favourable relationship between the habitat of NCS and the appearance of raptors within its landscape. In the beginning, i.e., in 2003 it was 10.5 and in 2016 it was 11.5 with fluctuations between values 5.7 and 15.3 (Table 2; Figure 5).
e) It is expected that the index values may enable to construe conclusion on conservation impacts from NCS with details of ecological parameters influencing the survival and behaviour of raptors through decades since the 1980s.

NCS-Kuno raptor names by other authors
a) Lists of NCS raptors that were possible to access for comparison are in Mitra (1979), the management  d) Given the gharial-oriented primary objectives, the season, and nature of our annual river surveys, we agree that our observations will not tally with other lists available for comparison. (Table 3) a) Bildstein et al. (1998) mentioned 63 diurnal raptor species in India. Naoroji (2011) mentioned the occurrence of a total of 44 raptor species in the semiarid biogeographic zone, of which 26 are migrants and 18 are residents. b) Since Chambal banks offer only the cliffs for limited perch or nest, we have attempted to compare our observed list with sanctuaries of Rajasthan that may be within the active home range of the raptors. c) Eleven raptor species observed in NCS are also reported from Ranthambhore Tiger Reserve (RTR) (Anonymous 2021) and Sariska Tiger Reserve (STR) (Sultana 2013

RECOMMENDATIONS
The National Chambal Sanctuary, which constitutes a part of river Chambal, is included under wetland types 11 (rivers, streams -slow-flowing, lower perennial) & 12 (rivers, streams -fast-flowing, upper perennial) (Scott 1989). As a protected area of national stature, river Chambal is provided with incidental conservation benefits for avian diversity. The river plays a crucial role in supporting local stork populations as well as giving alternate refuge for local migrants during the years with extreme ecological conditions . Similarly, continuous monitoring of wetland habitats in and outside Chambal may highlight the kind of ecological attraction Chambal holds for the skimmer populations of other wetlands in the region ).

Consideration for the tri-state Chambal Ramsar site
Based on field surveys we have reported in the past on the status and population trends of large shorebirds and Raptor species of NCS (Sharma & Singh 1986;Sharma et al. 1995Sharma et al. , 2013. The wetland and the adjoining area of the National Chambal Sanctuary form the habitat for many resident and migratory bird species, of which some are globally threatened. Our study on raptors identifies nine of the thirty raptors under the migratory category, attracted to the wetland landscape of NCS. A detailed study on the migration pattern of raptors and large shorebirds to River Chambal may further highlight the need for improved attention to river Chambal as a tristate Ramsar site of India. Madhya Pradesh has already initiated the proposal some years back and deserves coordination at the national level.

Review of Scheduled status for three species of raptors
As predators, the raptors form one of the top links in the ecological chain and are, therefore, indicators of the health of the environment (Naoroji 2011). Among the most effective predators, the birds of prey keep a constant check on the population of amphibians, reptiles, mammals, and birds, and even on themselves. Found in diverse habitats, they are among the first that are affected by chemical pollution, adverse exploitation, and an overall decline of the habitat. The results from the present study on raptors propose that the MoEFCC consider reviewing the status given under the Wildlife (Protection) Act to Cinereous Vulture Aegypius monachus, Egyptian Vulture Neophron percnopterus, and Red-headed Vulture Sarcogyps calvus.

A comprehensive study on raptors of Arid Biogeographic Region / Khathiar-Gir Eco Region
Studies on tiger by Reddy et al. (2012) have already suggested on-ground gene-pool continuity over RTR and Sawai Madhopur National Park (MNP), which are in Rajasthan on the northern side of NCS and the Kuno-Palpur Wildlife Sanctuary (KPWS) of Madhya Pradesh on the southern side of NCS. Only a future study on raptors would further confirm the nature of ecological connectivity of habitats on either side of the National Chambal Sanctuary through the air.
We expect some of the raptors in NCS are visitors from the adjoining habitats of Rajasthan and Madhya Pradesh, within the dry deciduous forest ecoregion. Tharmalingam et al. (2011) reported the presence of 19 raptor species in Kuno-Palpur of Madhya Pradesh, and the list doesn't show the presence of 16 raptors observed in our present list (Table 3). However, out of these 16 species, six are reported from Ranthambhore Tiger Reserve (RTR) and nine from Sariska Tiger Reserve (STR). The observations suggest some continuity in the distribution of raptors in the north and south of river Chambal.
The list of raptor birds given in the present study forms a base for time-related comparison of speciesavailability and for an impact assessment. It is urged, that detailed studies may be promoted on raptors seen in National Chambal Sanctuary and their possible home ranges extending through other perennial tributaries and forest habitats like those of Kuno and Shivpuri in Madhya Pradesh, and Ranthambhore and Sariska in Rajasthan.