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Observations of Isabela Oriole Oriolus Isabellae in
the Sierra Madre, Luzon, Philippines, with
Descriptions of the Call

MERLIJN VAN WEERD and ROB HUTCHINSON

The Isabela Oriole Oriolus isabellae is endemic to Luzon in the Philippines. It has been recorded from the Bataan Peninsula and from the Sierra Madre in Cagayan, Isabela and Quirino provinces (Collar et al.1999). There have only been two recent records: one individual in 1993 in secondary forest at 440 m in the foothills of the Sierra Madre in Quirino province (Gamauf and Tebbich 1995) and two individuals in 1994 on the edge of forest in the Sierra Madre in Cagayan province (Van der Linde 1995), neither of


which were considered absolutely certain (Collar 1998). The species is classified as Endangered (under criterion C1) because it has a small population, estimated to number 1,000–2,499 individuals, which is believed to be declining at a rate exceeding 20% in five years/two generations (BirdLife International 2000, 2001). Little is known of the ecology and of the behaviour of the species (Collar et al. 1999). Its call was hitherto unknown (Kennedy et al. 2000). Independently of each other, we observed a pair of Isabela Orioles in Ambabok, Disulap, municipality of San Mariano, Isabela province on 27 and 29 March 2003 (RH) and 25 and 26 May 2003 (MvW). In April 2004, one Isabela Oriole was captured here using a mist-net and released after documentation.

 

OBSERVATIONS

On the morning of 27 March, RH was birding close to the former settlement of Ambabok when he heard



Plates 1–3. Isabela Oriole Oriolus isabellae, April 2004, Ambabok, San Mariano, Isabela, Luzon, Philippines (Photographs by MvM).