Konyukhov and Kitaysky 



Chapter 2 



The Asian Race of the Marbled Murrelet 



Breeding Biology 



Pre-Laying Period 



The wintering grounds of the Asian subspecies are thought 

 to be situated around Hokkaido Island, Japan (excluding the 

 shore of the Okhotsk Sea), and the northern part of Honshu 

 Island (Brazil 1991). Although not identified with certainty 

 as to subspecies, the Marbled Murrelet is rarely found in the 

 waters of Kyushu, central Ryukyu, and the Amami Islands. 

 Scattered birds have been noted inshore of the Korean 

 Peninsula during the winter (Shibaev 1990). 



Timing of Breeding 



There are no direct observations of the length of the 

 breeding season. The approximate time of hatching and 

 fledging can be estimated from observations of fish-holding 

 behavior by adults and of young birds at sea. Birds with fish 

 were observed in the Amur River mouth in June (Shibaev 

 1990). A collected bird (ZMZI 168716/220-987) taken in 

 July 1979 had a brood patch beginning to refeather. 



Additionally, eggs and incubating birds have been found 

 during June through the years (table 1). Specifically, eggs 

 were found on 17 June 1961 and 23 June 1973 near the city 

 of Okhotsk and to the south (Kuzyakin 1963, Yakhontov 

 1979), on 21 June 1984 in southern Primorye Region 

 (Primorye), on 19 June 1976 on Northern Sakhalin Island 

 (Labzyuk, cited in Shibaev 1990; Nechaev 1986), and on 15 

 June on Eastern Hokkaido Island (Brazil 1991). Using these 

 data, Shibaev concluded (1990) that the breeding period is 

 generally similar in different parts of the breeding range. 



There is no information available about the duration of 

 either incubation period or the chick-rearing period. According 

 to Shibaev (1990), the chick-rearing period in southern parts 

 of the breeding region is in June- July. In the northern part of 

 the Sea of Okhotsk, we have observed murrelets carrying 

 fish from early July until late August. 



Characteristics of the Egg and Nest 



Only six Marbled Murrelet eggs have been found over 

 its vast breeding range in Russia, and three have been found 

 on the island of Hokkaido. All of the eggs in Russia were 

 found in the middle of June (table 1). Two of these eggs were 

 taken from oviducts of females. One was collected on the 



northwestern coast of the Sea of Okhotsk (58 30'N, 141 

 20'E) on 23 June 1977 (Yakhontov 1979), and the other on 

 Semyachik Spit (54 08'N, 160 02'E), Kamchatka Peninsula, 

 on 13 June 1993 (Ladygin, pers. comm.). The ground color 

 of most eggs is bluish-green or greenish-blue. Small markings 

 of pale brown, brown, and dark-cream or brownish-gray, 

 usually less than 2 mm in diameter, congregate near the blunt 

 end of the egg (Kistchinsky 1968b, Nechaev 1986, Yakhontov 

 1979). The pointed end is free of any marks (Kuzyakin 1963, 

 Nechaev 1986, Yakhontov 1979). Three measured eggs had 

 the following sizes: 63.6 x 39.3 mm and a weight of 48-50 g 

 (Kuzyakin 1963); 63 x 38 (or 39) mm (Yakhontov 1979); 

 66.2 x 39.0 mm and a weight of 53.7 g (Nechaev 1986). The 

 murrelet lays only one egg (Kistchinsky 1968b). 



All four nests in Russia were found in larch trees (Larix 

 daurica). The nest in the Okhotsk and Kukuchtui rivers area 

 (in the vicinity of the city of Okhotsk) was 6-7 km from the 

 shore, 7 m up on a branch with a broad base formed by 

 growth of several small limbs (Kuzyakin 1963). The egg 

 was laid on a piece of lichen (Bryopodon). The nest in the 

 Olga Bay area was in a tree, in a rocky coastal cliff area, and 

 2.5 m out on a branch similar to the above nest according to 

 Labzyuk (Shibaev 1990). The nest on Sakhalin Island was 2 

 km from Chay vo Inlet and 5 m up on the broken top of the 

 tree. The fourth nest was found in the Koni Peninsula near 

 Magadan city. Izmailov observed that the nest was 12 km 

 from the shore and 7 m up in the tree (Kondratyev and 

 Nechaev 1989). In Japan, three murrelet eggs were found on 

 the ground in mixed coniferous/broad-leaved forest on Mt. 

 Mokoto, 24 km inland from the Okhotsk Sea coast on the 

 island of Hokkaido on 15 June 1961 (Brazil 1991). 



Nest Attendance 



During the breeding season, murrelets often fly over the 

 forest and mountain summits uttering sharp shrill whistles. 

 In the morning, birds call from 0500 until 0700, seldom as 

 late as 0800. In the evening they call less often, beginning 

 about an hour prior to dusk (Nechaev 1986). 



From Shibaev's observations (1990), adults visit the 

 nest during the darker periods of the day in these high 

 latitudes. But in the northern part of the Sea of Okhotsk, we 

 have observed Marbled Murrelets carrying fish during both 

 the morning period and at times during the day. 



Table 1 Descriptions of Marbled Murrelet eggs found in Russia 



24 



USDA Forest Service Gen. Tech. Rep. PSW-152. 1995. 



