(J. Yamashina Inst. Ornithol.), 42: 143῍146, 2011 ῌYamashina Institute for Ornithology Short Note ῍ῒ ΐ῎ First Description of the Nest and Eggs of the Calayan Rail Carl H. Oliveros1), 2) and Cynthia Adeline A. Layusa1) Abstract. We describe for the first time the nest and eggs of the Calayan Rail Gallirallus calayanensis. The nest was built on the ground at the base of a fig tree and loosely constructed with dried leaves and stems. The eggs were pale pink and blotched reddish-brown and dark lilac, measuring 35 mm25 mm in size. Nest placement, construction and egg coloration was similar to its congener, the Okinawa Rail G. okinawae. Key words: Breeding ecology, Calayan Island, Gallirallus calayanensis, Philippines.  Gallirallus calayanensis   ῏ῌῑῌῐ  The Calayan Rail Gallirallus calayanensis is a recently discovered near-flightless species endemic to the small (196 km2) island of Calayan in the northern Philippines (Allen et al. 2004). Presently classified as Vulnerable to extinction under the IUCN Red List (IUCN 2009), recent field surveys have found that the species occurs throughout most of the island’s forests (Oliveros et al. unpublished data). However, little information is known about its breeding ecology apart from observations of young individuals and secondary information from local residents. On 2 June 2009 while carrying out field surveys in the east central portion of Calayan Island (N 1917.411 E 12131.025 at an altitude of 170 m) a survey team including one of us (C. H. Oliveros) flushed a Calayan Rail along the banks of the Dibnong Stream at 08 : 53 h. Further inspection of the area revealed a nest with three eggs (Fig. 1). The Calayan Rail nest was situated on the ground near the buttress of a fig tree Ficus congesta concealed amongst undergrowth of Odontonema strictum and exposed rocks in disturbed old growth forest (Fig. 1). Located 2 m away from a dry seasonal stream, the nest was a loose construction of dried leaves and stems forming a very shallow cavity 12 cm in diameter. The eggs were pale pink with blotches of reddish-brown and dark lilac. Each egg was elliptical and measured approximately 35 mm25 mm in size. The chorus calls of at least two Calayan Rails were heard 25 m away during the nest observation period. Digital photographs and video recordings of the nest site were taken. During a subsequent visit to the nest on 4 June 2009 three eggs were present but no attendant rail was observed. This Calayan Rail nest and eggs are the first to be encountered in five years of rail Received 17 June 2010, Revised 26 September 2010, 2nd Revision 28 September 2010, Accepted 1 October 2010. 1) Isla Biodiversity Conservation, 9 Bougainvillea St., Manuela Subdivision, Las Piñas City 1740, Philippines. 2) Department of Ecology and Evolutionary Biology, University of Kansas, 1345 Jayhawk Blvd., Lawrence, KS 66045, U.S.A. 143 144 Carl H. Oliveros and Cynthia Adeline A. Layusa Fig. 1. (A) Calayan Rail nest and eggs; (B) Nest (shown by arrow) near the buttress of fig tree and herbaceous undergrowth; (C) Habitat near nest location, showing seasonal stream. First Description of the Nest and Eggs of the Calayan Rail 145 survey work on Calayan, although fledged rail chicks have been observed as early as 6 April (C. Española and Oliveros unpublished data) and juveniles have been observed during the month of May (Allen et al. 2004). The discovery of the nest and eggs extends the known breeding period of the species to June. Our observation of three eggs in the nest is consistent with anecdotal information from local residents that indicates clutch size to vary from 3 to 7 (C. Española and Oliveros, unpublished data) although the upper limit has yet to be verified. The nest placement and construction of this species is similar to that of the Okinawa Rail G. okinawae, another island-endemic forest specialist. Eggs of both species are also similar in color, except that Calayan Rail eggs have smaller sized blotches that are more numerous and more spread out throughout the egg; however, Calayan Rail eggs are smaller in size (Chigira et al. 1993; K. Ozaki, unpublished data). We recommend further research on the ecology and breeding biology of the Calayan Rail to enable sound conservation initiatives for the species, as ground nesting birds endemic to small islands are especially vulnerable to extinction (Duncan & Blackburn 2004). Acknowledgements We wish to thank members of our survey team J. Reynon, N. Navarro, M. Navarro, R. Ventura and J. Visario for their tireless e#orts in the field and o$cials of the Calayan municipal government and the Department of Environment and Natural Resources for their support. P. Hosner provided comments and suggestions to improve this paper. K. Ozaki provided us photos of the nest and eggs of the Okinawa Rail and H. Macarambon helped translate literature in Japanese. Our surveys have been made possible through technical and financial support of the Conservation Leadership Programme. References Allen, D., Oliveros, C., Española, C., Broad, G. & Gonzalez, J. C. T. 2004. A new species of Gallirallus from Calayan Island, Philippines. Forktail 20: 1ῌ7. Chigira, Y., Ikehara, S. & Takehara, K. 1993. Notes on the Breeding of Okinawa Rail, Rallus okinawae Yamashina and Mano. Bulletin of Culture Division, Education Department, Okinawa Prefecture 9: 1ῌ11. (In Japanese) Duncan, R. P. & Blackburn, T. M. 2004. Extinction and endemism in the New Zealand avifauna. Global Ecology and Biogeography 13: 509ῌ517. IUCN 2009. IUCN Red List of Threatened Species. Version 2009. 2. www.iucnredlist.org. Downloaded on 11 February 2010.     Gallirallus calayanensis      !"#$%&' ()*+,-./012)* 3)45-' 675% )895:;%&' <=> 35 mm ? 25 mm -%@* AB' CD' 5EF G. okinawae $I)* GH 146 Carl H. Oliveros and Cynthia Adeline A. Layusa Carl H. Oliveros: Isla Biodiversity Conservation, 9 Bougainvillea St., Manuela Subdivision, Las Piñas City 1740, Philippines. Department of Ecology and Evolutionary Biology, University of Kansas, 1345 Jayhawk Blvd., Lawrence, KS 66045, U.S.A. Cynthia Adeline A. Layusa: Isla Biodiversity Conservation, 9 Bougainvillea St., Manuela Subdivision, Las Piñas City 1740, Philippines.