Journal of Threatened Taxa | www.threatenedtaxa.org | 26 October 2018 | 10(11): 12566–12570

A winter roost count of the Short-eared Owl Asio flammeus (Aves: Strigiformes: Strigidae) at Porbandar, Gujarat, India

Dhavalkumar Varagiya ¹ & Anita Chakraborty ²

¹ School of Pharmacy, RK University, Rajkot-Bhavnagar Highway, Kasturbadham, Rajkot, Gujarat 360020, India

² Department of Botany, SSLNT Mahila Mahavidlaya, Luby Circular Road, Dhanbad, Jharkhand 826001, India

¹ dhaval.mwcc@gmail.com (corresponding author), ² anitagcenator@gmail.com

Abstract: The Short-eared Owl Asio flammeus is a common to uncommon winter visitor to Gujarat. The species roosted in bushes of Prosopis juliflora in the grassland of Shiroda area, Odadar Village of Porbandar District. Communal roosts were identified by foot surveys between 9–17 November 2016. A total of 20 individuals co-existed with grazing cattle in the grassland of ca. 1km². At present due to their restricted nesting habits and nomadic nature, the species is vulnerable to habitat loss at their feeding and roosting grounds. Conversion of open habitats to agriculture, grazing, recreation, housing and tourism development are the current threats to the species in the wetland complex. The IUCN conservation status further confirms that though they are assessed as Least Concern, in spite of the species population constantly declining with global population estimated at 3,000,000 individuals which equates to 2,000,000 mature individuals. The present study is the first systematic attempt to count a roost in Gujarat.

Keywords: Gujarat, IUCN, Porbandar, Short-eared Owl, wetland, wintering roost.

doi: https://doi.org/10.11609/jott.3617.10.11.12566-12570

Editor: Reuven Yosef, Ben Gurion University of the Negev, Eilat, Israel. Date of publication: 26 October 2018 (online & print)

Manuscript details: Ms # 3617 | Received 30 June 2017 | Final received 12 September 2018 | Finally accepted 02 October 2018

Citation: Varagiya, D. & A. Chakraborty (2018). A winter roost count of the Short-eared Owl Asio flammeus (Aves: Strigiformes: Strigidae) at Porbandar, Gujarat, India. Journal of Threatened Taxa 10(11): 12566–12570; https://doi.org/10.11609/jott.3617.10.11.12566-12570

Copyright: © Varagiya & Chakraborty 2018. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

Funding: Field work was self funded by Dhavalkumar Varagiya.

Competing interests: The authors declare no competing interests.

Acknowledgements: We are thankful to Kishore Joshi, Bhaskar Thankey, Vijay Jethva, Nayan Thanki, Vikrant Rana, Punit Karia, Zeel Badiyani, Konark Karia for joining us during surveys voluntarily.

The Short-eared Owl Asio flammeus is a widespread winter migrant to India (Blanford 1894). It prefers grassland and open country (Ali & Ripley 1987). In India, it is reported from Maharashtra (Jamdar & Shrivastava 1988; Chandrasekaran 1995), Madhya Pradesh (Pasha et al. 2004), Tamil Nadu (Thyagaraju 1933), Kerala (Jayson & Mathew 2002; Chandrasekhara & Nameer 2003), Gujarat (19 November 1993 specimen: The Field Museum), Rajasthan (5 January 1949 specimen: The Field Museum; Singh 1997), Karnataka (20 January 1941 specimen: The Field Museum), Uttar Pradesh (Grewal 2000), Andhra Pradesh (Kanniah & Ganesh 1993) and other states.

The Short-eared Owl has an extremely large range, and therefore it does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000km² combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation) as well as under the population trend criterion (>30% decline over 10 years or three generations) and population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in 10 years or three generations, or with a specified population structure) in IUCN conservation status evaluation. For these reasons the species is designated as Least Concern.

At present, due to their restricted nesting habits and nomadic nature, the species is vulnerable to habitat loss on their feeding and roosting grounds. Conversions of open habitats to agriculture, grazing, recreation, housing and tourism development are the current threats to the species in the wetland complex.

The Short-eared Owl is a common to uncommon winter visitor to Gujarat (Ganpule 2016). The species is usually present from September/October to March/April in the Indian Subcontinent (Grimmett et al. 1998; Ali & Ripley 2001; Srinivasulu & Srinivasulu 2007).

The species usually nests and roosts on the ground and prefers grassland habitat. It is often seen flying low like harriers; its opportunistic diet consists mainly of small mammals and rarely small birds. It is an active hunter, flying low over the ground (less than 6 feet) in search of prey; usually hovers and drops vertically pouncing on prey. The species is considered to be a highly migratory in the northern limits of its global range. Banding data shows 1,000-mile movements in 50 days. These movements also vary and large movements are often related to juvenile dispersals. The longevity record for a Short-eared Owl in the wild is 13 years (Rumet 2012).

Material and Methods

Observations and counts were recorded in November 2016 for nine days in the Shiroda region, located between Odadar and Mokar villages of Porbandar District (Fig. 1). It is located about a distance of 5km from Porbandar Somnath National Highway and connected by a tar road with Odadar and Mokar villages. The study area is Gosabara Mokarsagar Wetland Complex (here after Mokarsagar) which was declared an Important Bird and Biodiversity Area by the Bombay Natural History Society and Birdlife International in March 2017 (Rahmani et al. 2016).

Mokarsagar (21.565⁰N & 69.764⁰E) is the largest wetland of Porbandar District and spread across 106km². The wetland complex supports more than 20,000 waterbirds annually and thus is shortlisted as a potential Ramsar site as well as Biodiversity Heritage Site. Recently, a public interest litigation has been also filed in Gujarat High Court to declare it as a wildlife sanctuary.

The wetland complex is drained by the Bhadar River, the longest river of the Saurashtra region along with River Billeshwari (Minsar). Before the 1970s, the region was an intertidal mudflat due to the ingress of sea water through the mouth close to Gosabara (21.535⁰N & 69.710⁰E) which mixed with fresh water during the monsoon season. The culvert was created near Gosa Village and resident fishermen used fixed oja nets for catching Prawns Penaeus penicillatus (Mansuri 1986). Gradually the tidal influx started impacting the soil and fresh water biota of the region. In order to prevent and control the impacting phenomenon Salinity Ingress Prevention Cell (SIPC), Gujarat, built structures across the creek such as tidal regulators (masonry wall) and bunds at different locations (Singh et al. 2014). These structures prevented the free flow of tidal ingress. As a result prawn fishing was stopped but the quality of agricultural soil improved.

In Mokarsagar, there are four elevated inland islands which usually do not get submerged during the peak monsoon (because the islands lie at about 4–6 m above sea level and the Mokarsagar is at sea level). Shiroda is one amongst these four islands mainly used by the Odadar villagers for grazing livestock.

The wetland complex has been monitored since 2012 for water as well as terrestrial bird count, the frequency is once every month of the year. On 9 November 2016, during the survey in Shiroda, one Short-eared Owl was observed and photographed in the bushes close to the road (Image 1). The bird was not disturbed and count and observation plan was structured to survey the region for the total wintering population of the species.

It was assumed that the Short-eared Owl will be present on all of the four islands of Mokarsagar. Starting from Shiroda, all islands were surveyed for presence of Short-eared Owls. The region was diligently surveyed on foot (after Fuller & Mosher 1987). Randomly, 500m long transect lines (total nine) were conducted in the study area. Walking the transects and counting of roosting birds on both sides and locations were geo-tagged with Garmin eTrex® 30x Handheld GPS device. Apart from Shiroda, the Short-eared Owl was not found on any of the other islands of Mokarsagar. Thus, the data presented is from Shiroda only.

Observation and Discussion

The species was found to roost in bushes of Prosopis juliflora on Shiroda island. Realizing the fact that the species was spotted for the first time, an effort for identifying communal roosts was undertaken by going on foot surveys. A total 20 individuals (Table 1) were observed to co-exist with grazing cattle in the grasslands spread over an area of 1km² between November 9–17, 2016 (Table 2; Fig. 2). The species prefers bushes to hide (Image 2) but, when unknowingly disturbed by cattle herders, it flies to refuge areas as shown in Fig. 1. The refuge area covers 0.14km² with dense vegetation of Proposis spp. along with grasses.

The species was observed to co-exist with mammals like Golden Jackal Canis aureus, Bengal Fox Vulpes bengalensis, Jungle Cat Felis chaus, Nilgai Boselaphus tragocamelus, Wild Boar Sus scrofa, and domestic cattle Bos domesticus. The species was also observed to co-exist with 48 bird species (Table 2). No attempts were made to study its interactions with other species. Generally, it remains silent during wintering stage thus no call was observed.

The current sighting of the Short-eared Owl in Porbandar is the first published record for the district as it was not mentioned in previous checklists (Meena & Kumar 2014). Foot surveys were repeated for three days on the same transects and a maximum number of the owls were observed on the third day (i.e., 17 November 2016). Prey base and feeding ecology were not studied, however, we speculate that there is abundant prey at Shiroda Island & its adjacent farmlands, and the dense vegetation of Prosopis juliflora along with grass provide spaces roosting and sheltering. The present study is the first systematic attempt to count Short-eared Owls in Gujarat and reports the highest wintering roost congregation of the species.

Based on our limited study and data, we recommend that the management measures should maintain large contiguous tracts of wetland, and grassland habitat for the species and their prey. Controlled human disturbance and predation as well as possible, public education, and continued field research is required.

Table 1. Observation chart

Date	Time (hrs)	Comments
09.xi.2016	18:00	Area is mainly grassland with scattered Prosopis juliflora; location was also very close to a ‘kacha’ road less frequently used
10.x.2016	16:00–18:00	Bird was found at same place but remain stable and hidden.
11.xi.2016	18:15	Bird was spotted about 200m away from previous site from the road
13.xi.2016	16:00–18:00	Observed two pairs (4 individuals) from the road
14.xi.2016	16:00–18:00	Observed 12 individuals by foot survey
16.xi.2016	16:00–18:00	Observed 14 individuals by foot survey
17.xi.2016	16:00–19:00	Observed 20 individuals by foot survey

Table 2. Bird Species observed to coexist with Short-eared Owl

	Bird Species	Status in Gujarat (Ganpule 2016)
1	Common Quail Coturnix coturnix	Common winter visitor
2	Grey Francolin Francolinus pondicerianus	Common resident
3	Cattle Egret Bubulcus ibis	Common resident
4	Short-toed Snake-Eagle Circaetus gallicus	Common to uncommon resident
5	Eurasian Marsh-Harrier Circus aeruginosus	Common winter visitor
6	Pallid Harrier Circus macrourus	Common to uncommon winter visitor
7	Montagu's Harrier Circus pygargus	Common winter visitor
8	Shikra Accipiter badius	Common resident
9	Indian Thick-knee Burhinus indicus	Common resident
10	Yellow-wattled Lapwing Vanellus malabaricus	Common resident
11	Red-wattled Lapwing Vanellus indicus	Very Common resident
12	Kentish Plover Charadrius alexandrinus	Common resident and local winter migrant
13	Barred Buttonquail Turnix suscitator	Resident and fairly common resident
14	Chestnut-bellied Sandgrouse Pterocles exustus	Common resident
15	Rock Pigeon Columba livia	Very common resident
16	Eurasian Collared-Dove Streptopelia decaocto	Common resident
17	Greater Coucal Centropus sinensis	Common resident
18	Sykes's Nightjar Caprimulgus mahrattensis	Uncommon winter visitor
19	Indian Nightjar Caprimulgus asiaticus	Common resident
20	Green Bee-eater Merops orientalis	Common resident
21	Eurasian Kestrel Falco tinnunculus	Common winter visitor
22	Isabelline Shrike Lanius isabellinus	Winter visitor
23	Bay-backed Shrike Lanius vittatus	Common resident
24	Long-tailed Shrike Lanius schach	Common resident
25	Southern Grey Shrike Lanius meridionalis	Common resident
26	Black Drongo Dicrurus macrocercus	Very common resident
27	Rufous-tailed Lark Ammomanes phoenicura	Very common resident
28	Ashy-crowned Sparrow-Lark Eremopterix griseus	Very common resident
29	Indian Bushlark Mirafraery throptera	Common resident
30	Greater Short-toed Lark Calandrella brachydactyla	Common winter visitor
31	Sand Lark Alaudala raytal	Common resident
32	Crested Lark Galerida cristata	Common resident
33	Red-vented Bulbul Pycnonotus cafer	Very common resident
34	Sykes's Warbler Iduna rama	Common winter visitor
35	Common Tailorbird Orthotomus sutorius	Common resident
36	Plain Prinia Prinia inornata	Common resident
37	Lesser Whitethroat Sylvia curruca	Common winter visitor
38	Common Babbler Turdoides caudata	Very common resident
39	Large Grey Babbler Turdoides malcolmi	Very common resident
40	Jungle Babbler Turdoides striata	Common resident
41	Indian Robin Copsychus fulicatus	Common resident
42	Oriental Magpie-Robin Copsychus saularis	Common resident
43	Rosy Starling Pastor roseus	Very common winter visitor
44	Purple Sunbird Cinnyris asiaticus	Common resident
45	Paddyfield Pipit Anthus rufulus	Common resident
46	Long-billed Pipit Anthus similis	Common winter visitor
47	Tawny Pipit Anthus campestris	Common winter visitor
48	Indian Silverbill Euodice malabarica	Common resident

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