Ornithol Sci 11: 109 – 112 (2012)

SHORT COMMUNICATION An Eastern Crowned Phylloscopus coronatus nest parasitized by an Oriental saturatus with a reddish in Hokkaido,

Sayaka MORI1,#, Yuka KONDO2 and Hiroyoshi HIGUCHI3

1 Center for Molecular Biodiversity Research, National Museum of Nature and Science, Tokyo, 4–1–1 Amakubo, Tsukuba-shi, Ibaraki 305–0005, Japan 2 Laboratory of Wildlife Ecology, Obihiro University of Agriculture and Veterinary Medicine, 2–11 Inada-cho Nishi, Obihiro-shi, Hokkaido 080–8555, Japan 3 Graduate School of Media and Governance Doctoral Program, Keio University SFC, Endo 5322, Fujisawa-shi, Kanagawa 252–0882, Japan

Abstract The distributions of the Little Cuculus poliocephalus and Oriental C. ORNITHOLOGICAL saturatus differ throughout Japan. In Honshu, the Little Cuckoo parasitizes SCIENCE mainly the Japanese Bush Warbler Cettia diphone and lays reddish mimetic . The © The Ornithological Society Oriental Cuckoo mainly parasitizes the Eastern Crowned Leaf Warbler Phylloscopus of Japan 2012 coronatus and lays whitish eggs. However, in central Hokkaido, where no Little Cuckoos breed, Oriental Cuckoos parasitize Japanese Bush Warblers as their main hosts, in whose nests they lay reddish eggs. Anecdotal evidence suggests that they also parasitize Eastern Crowned Leaf Warblers, laying reddish eggs, but this has not been confirmed. Here, we report the first complete evidence in which an Oriental Cuckoo chick, which hatched from a non-mimetic reddish egg, was raised by Eastern Crowned Leaf Warbler hosts in Hokkaido.

Key words Brood parasitism, Cuculus saturatus, Hokkaido, Phylloscopus coronatus, Reddish egg

The distributions of the Little Cuckoo C. Cuckoos parasitize the Japanese Bush Warbler, lay- poliocephalus and the Oriental Cuckoo C. saturatus ing reddish eggs (Higuchi & Sato 1984). These red- differ throughout Japan. They both breed in Honshu dish eggs are significantly larger than the whitish (the largest main island), whereas in Hokkaido (the eggs of conspecifics in Honshu, corresponding to the northernmost, and second largest island), the Little larger egg size of Japanese Bush Warblers than those Cuckoo is rare with its range restricted to the south- of Eastern Crowned Leaf Warblers (Higuchi 1998). ern part of the Oshima peninsula (the southwestern- It has been suggested that the Oriental Cuckoo in most part of Hokkaido) (Biodiversity Center of Japan Hokkaido might also parasitize the Eastern Crowned 2004). In Honshu, the main host of the Little Cuckoo Leaf Warbler, which is its main host in Honshu. is the Japanese Bush Warbler Cettia diphone, while However, there has hitherto been no conclusive evi- the Oriental Cuckoo parasitizes the Eastern Crowned dence that Oriental Cuckoo chicks hatch and are Leaf Warbler Phylloscopus coronatus predominantly raised by Eastern Crowned Leaf Warbler hosts. For (Higuchi 1998). The eggs of both cuckoo species example, reddish eggs have been found in four East- match the colour and size of their main hosts: Little ern Crowned Leaf Warbler nests in Hokkaido Cuckoos lay reddish eggs similar in color to those (Nakanishi 1942; Higuchi & Ozaki 1994; Kawaji of Japanese Bush Warblers, and Oriental Cuckoos 2009; Kamioki et al. 2011), although the cuckoo spe- lay whitish eggs like those of Eastern Crowned cies were unknown. In the first three cases, the nests Leaf Warblers (Higuchi 1998). However, in central were depredated before hatchlings were confirmed. Hokkaido where no Little Cuckoos breed, Oriental In the last case, the reddish egg did not hatch while the host nestlings fledged successfully. In another (Received 19 October 2011; Accepted 8 September 2012) incomplete observation, a fledgling Oriental Cuckoo # Corresponding author, E-mail: [email protected] was found in an unidentified Phylloscopus warbler

109 S. MORI et al. nest (Yoshiro Ijima personal communication. See egg. The parasitized nest of the Eastern Crowned also Higuchi & Ozaki 1994). In this case, the egg Leaf Warbler was found on 9 June 2010 on the color was unknown. Here, we document the first ground in a deciduous shelterbelt which consisted complete case, from egg to fledgling, in which an mainly of Japanese Emperor Oaks Quercus dentata Oriental Cuckoo chick, which hatched from a non- and Japanese Elms Ulmus davidiana, with a ground mimetic reddish egg, was raised by Eastern Crowned cover of dense bamboo Sasa nipponica. The nest was Leaf Warbler hosts in Hokkaido. dome-shaped with a side entrance, and mainly made of dried leaves of poaceous grasses. We monitored MATERIALS AND METHODS the parasitized nest until early July to identify the cuckoo species based on the morphological charac- The study area is a fragmented in agricul- teristics of the nestling (Higuchi & Payne 1986; Tojo tural land south of Obihiro city in eastern Hokkaido, et al. 2002). The length and width of eggs were mea- Japan (42°46′N, 143°05′E). Three Eastern Crowned sured by placing them on a tape measure and reading Leaf Warbler nests were found in the period 2006– the scale from directly above. 2010, of which one nest contained a reddish cuckoo

Fig. 1. An Eastern Crowned Leaf Warbler’s nest parasitized Fig. 2. The Oriental Cuckoo nestling that hatched from the by an Oriental Cuckoo’s reddish egg. June 9, 2010, Obihiro, reddish egg in Fig. 1. It was 4–5 days old and had prominent Hokkaido, Japan. gape patches on June 21, 2010.

Fig. 3. The Oriental Cuckoo nestling that hatched from the Fig. 4. The Oriental Cuckoo nestling that hatched from the reddish egg in Fig. 1 at 11–12 days of age on June 28, 2010. reddish egg in Fig. 1 at 16–17 days of age, showing specific plumage of this species on July 3, 2010.

110 A reddish cuckoo egg in a Phylloscopus warbler nest

RESULTS nests (Higuchi 1998). This is the first complete evidence of an Oriental The parasitized nest contained six white eggs and Cuckoo parasitizing an Eastern Crowned Leaf one reddish egg (Fig. 1). One white egg measured Warbler nest, and laying a reddish egg in Hokkaido, 19×11 mm and the reddish egg 22×15 mm. We mea- with both egg and chick morphologies being con- sured only one white egg to avoid further distur- firmed. This observation suggests that previous bance. On 21 June, one 4–5 days old cuckoo nestling instances of reddish eggs being found in Eastern was found in the nest with no trace of the host nest- Crowned Leaf Warbler nests in Hokkaido might have lings or eggs around the nest. Distinct black patches also involved Oriental Cuckoos (Nakanishi 1942; were visible on the flange near the tip of both upper Higuchi & Ozaki 1994; Kawaji 2009; Kamioki et al. and lower mandibles, while the rest of the gape was 2011). bright orange (Fig. 2). On 25 June, the 8–9 days old The Japanese Bush Warbler is known to be highly nestling had growing feathers covered by sheaths and capable of discriminating against eggs differing in dark blackish feathers covering the dorsal part of the color from its own and it shows a strong tendency body and the head. On 28 June, the 11–12 days old to abandon nests that have been parasitized with nestling was large enough to completely fill the nest. such odd-looking eggs (Higuchi 1989). Conversely, Although its feathers had not finished growing, the Phylloscopus warblers in Japan, which lay whit- feathers on its head, face, throat and breast were ish eggs, do not discriminate against eggs based on blackish brown while those on the rest of the ventral color and so accept eggs in dissimilar colors (Higuchi parts appeared to show black and white banding 1998). The Little Cuckoo does not inhabit most of (Fig. 3). On 3 July, the nestling was 16–17 days old Hokkaido, thus Japanese Bush Warbler nests are and was almost fully grown. The body size exceeded available for the Oriental Cuckoo without competi- the capacity of the nest and the nestling could walk tion. In this context, the Japanese Bush Warbler’s around the nest. Feathers on the dorsal surface, throat greater discriminatory ability may have increased the and breast were dark blackish-brown with faint white selection pressure on the color and size of the eggs fringes. There was also a white patch on the head. of the Oriental Cuckoo in Hokkaido. This selection The ventral parts were banded with dark blackish pressure may have driven the evolution of reddish brown and white (Fig. 4). These morphological traits eggs in order for Oriental Cuckoos to successfully are all consistent with previous descriptions of the parasitize Japanese Bush Warblers. However, Ori- Oriental Cuckoo. On 6 July, we checked the nest but ental Cuckoos may also parasitize Eastern Crowned found no sign of parents or the nestling, which had Leaf Warblers, and more so in areas of low Japanese seemingly fledged successfully. Bush Warbler abundance, simply because they are abundantly available. DISCUSSION Higuchi (1998) reported that Japanese Bush War- blers were the major host of Oriental Cuckoos in We identified the cuckoo nestling as an Oriental central Hokkaido, where Japanese Bush Warblers Cuckoo by comparing the nestling’s morphological were common. In the study area, Eastern Crowned characteristics with previously published descriptions Leaf Warblers breed commonly, but Japanese Bush of cuckoo nestlings. First, the conspicuous black Warblers are rare (Anada & Fujimaki 1984; Fujimaki gape patches are consistent with the characteristic 1984; Biodiversity Center of Japan 2004). Therefore, markings of nestling Oriental Cuckoos (Tojo et al. Oriental Cuckoos in the study area only parasitize 2002). Second, the blackish brown feathers on the Eastern Crowned Leaf Warblers. One out of three dorsal parts, and on the face, throat and breast, and Eastern Crowned Leaf Warbler’s nests was found to the black and white banding of the ventral feathers of be parasitized by Oriental Cuckoos with a reddish the nestling just before fledging indicated that the egg. Another recent study at another site in Sapporo nestling was an Oriental Cuckoo (Higuchi & Payne (western Hokkaido) with low Japanese Bush Warbler 1986). Third, the white patch on the head is also a abundance (Kawaji 2009) reported that three out of documented trait of Oriental Cuckoo nestlings five Eastern Crowned Leaf Warbler nests were para- (Higuchi & Payne 1986). Finally, the reddish egg sitized with reddish eggs that were presumed to have color and egg size were within the range of those of been laid by Oriental Cuckoos (Kamioki et al. 2011). Oriental Cuckoos parasitizing Japanese Bush Warbler These results suggests that parasitism of Eastern

111 S. MORI et al.

Crowned Leaf Warblers by Oriental Cuckoos might for female host-specific races of the . be relatively common. Nature 407: 183–186. The Common Cuckoo has several host-specific Higuchi H (1989) Responses of the Bush Warbler Cettia races (gentes) wherein females of each race have a diphone to artificial eggs of Cuculus cuckoos in preference for a specific host species and typically lay Japan. Ibis 131: 94–98. eggs that match those of their hosts, and each type of Higuchi H (1998) Host use and egg color of Japanese egg might be maternally inherited (Marchetti et al. Cuckoos. In: Rothstein SI & Robinson SK (eds) Par- 1998; Gibbs et al. 2000). Such specific races may not asitic and Their Hosts —Studies in coevolu- exist in Oriental Cuckoos, at least in Hokkaido, since tion—. pp 80–93. Oxford University Press, Oxford. there only a single egg morph has been found, i.e., Higuchi H & Ozaki K (1994) A case of parasitic reddish egg in the nest of Crowned Willow Warblers Phyl- the reddish form, which only mimics Japanese Bush loscopus occipitalis in Hokkaido, northern Japan. Warblers’ eggs. Strix 13: 227–229 (in Japanese with English abstract). Higuchi H & Payne RB (1986) Nestling and fledgling ACKNOWLEDGMENTS plumages of Cuculus saturatus horsfieldi and C. poliocephalus poliocephalus in Japan. Jap J Ornithol We are grateful to Dr. Craig Barnett for helpful comments 35: 61–65. on an early draft. We thank Drs. Hisashi Yanagawa, Tatsuo Oshida, and other members at the Laboratory of Wildlife Higuchi H & Sato S (1984) An example of character Ecology of Obihiro University of Agricultural and Veterinary release in host selection and egg colour of cuckoos Medicine, for supporting our fieldwork. We also thank two Cuculus spp. in Japan. Ibis 126: 398–404. anonymous reviewers for their valuable comments and sug- Kamioki M, Kawaji N, Kawaji K & Ueda K (2011) gestions. Reddish cuckoo eggs found on the Urosphena squameiceps and the Phylloscopus coronatus nest in Hokkaido. REFERENCES Strix 27: 97–103 (in Japanese with English abstract). Anada S & Fujimaki Y (1984) Avifauna of agricul- Kawaji N (2009) An example of a reddish Oriental tural land and residential area in Obihiro, eastern Cuckoo Cuculus saturates egg in a Japanese White- Hokkaido, during the breeding season. Strix 3: 19–27 eye’s Zosterops japonicus nest. Jpn J Ornithol 58: (in Japanese with English abstract). 98–102. Biodiversity Center of Japan (2004) The national survey Marchetti K, Nakamura H & Gibbs HL (1998) Host- on the natural environment report of the distribu- race formation in the Common Cuckoo. Science 282: tional survey of Japanese (Birds). Biodiver- 471–472. sity Center of Japan, Yamanashi (in Japanese). Nakanishi G (1942) Yacho wo tazunete (In search of Fujimaki Y (1984) Birds of Tokachi district, Hokkaido. Wild birds). Nisshin Shoin, Tokyo (in Japanese). 4. Birds of agricultural land. J Yamashina Inst Orni- Tojo H, Nakamura S & Higuchi H (2002) Gape patches thol 16: 159–167 (in Japanese with English abstract). in Oriental Cuckoo Cuculus saturatus nestlings. Gibbs HL, Sorenson MD, Marchetti K, Brooke MdeL, Ornithol Sci 1: 145–149. Davies NB & Nakamura H (2000) Genetic evidence

112