Response to “Discovery of a possible hybrid of the Critically Endangered Forest Owlet Athene blewitti and Spotted Owlet Athene brama (Aves: Strigiformes) from northern Maharashtra, India” by Pande et al.
Wildlife Conservation Society, Bronx Zoo, Bronx, NY
Current address: 2 Dutter End, Gamlingay, Sandy,SG19 3EY
The recently published article by Pande et al. (2011) in the JoTT explores speculation on natural hybridization between two closely-related species of owlets using behavioural and phenotypic data. I am left unconvinced by the data presented to verify the hybridization. It is interesting to read that the authors observed a family of owlets with “intermediate” plumages, behaviours and vocalizations defending the territory with a recently fledged young owlet, concluding that it was a fertile hybrid of the two species. A rather too brief description on plumage and behaviour has been given along with a comparison of vocalization duration but no information at all on “intermediate” vocalizations. Given that the call of both Forest Owlet and Spotted Owlet is very distinctive, it would be useful to know the “intermediate” call of the observed family. In addition, the Forest Owlet’s call varies during the breeding season, especially when accompanied by a juvenile and is described in detail by Ishtiaq & Rahmani (2005). The “intermediate” vocalization mentioned however needs further clarification. The authors also mention that “To date, juvenile owlets have not been fully characterized”. The juveniles of the Forest Owlet are remarkably similar to the adult birds except a bit more spotted brown crown but certainly do not look like Spotted Owlet (see Ishtiaq 2000 for photograph and Ishtiaq & Rahmani 2005 for details on Forest Owlet, and Kumar 1980 for Spotted Owlet). Finally, based on video 2 referred to as ‘hybird’, it appears to be a Spotted Owlet, not showing any features of Forest Owlet or if it does then these need to be highlighted. Also, authors observed and filmed the “hybrid” female engaged in extra-pair copulation (EPC) with the neighbouring male Forest Owlet. I believe this video would be more relevant to demonstrate the interaction between the two species.
Finally, I am surprised to see that the authors still consider the Forest Owlet to be in the Athene genus. The Forest Owlet has long been placed in the genus Athene with which the specimens show strong superficial resemblance. However, based on the osteological evidence (BirdLife International 2001), and behavioural observations (Rasmussen & Ishtiaq 1999; Ishtiaq & Rahmani 2005), it’s placement in its own genus Heteroglaux, as originally suggested by Hume (1873) has been considered as well justified.
BirdLife International (2001). Threatened Birds of Asia: The BirdLife International Red Data Book. Cambridge, UK: BirdLife International
Kumar, S.T. (1980). The life-history of the Spotted Owlet (Athene brama brama Temminck) in Andhra Pradesh. Raptor Research Centre, Hyderabad. Publication No. 4.
Ishtiaq, F. 2000. Enigma of the Forest Owlet. Sanctuary Asia XX(3): 32–39.
Ishtiaq, F. & A.R. Rahmani (2005). The Forest Owlet Heteroglaux blewitti: vocalization, breeding biology and conservation. Ibis 147: 197–205.
Pande, S.A., A.P. Pawashe, R. Kasambe & R. Yosef (2011). Discovery of a possible hybrid of the Critically Endangered Forest Owlet Athene blewitti and Spotted Owlet Athene brama (Aves: Strigiformes) from northern Maharashtra, India. Journal of Threatened Taxa 3(4): 1727–1730.
Rasmussen, P.C. & F. Ishtiaq (1999). Vocalizations and behaviour of the Forest Owlet Athene (Heteroglaux) blewitti. Forktail 15: 61–65.