Recently published research about Common Murres (Uria aalge) along the Oregon Coast allows us to examine the biology of murres in more detail than has been previously possible. The following synthesis about murres along the Oregon Coast is adapted from Bayer and Ferris (1987:15-16).

Murres can first land on their Oregon nesting colony in mid-winter but do not frequently do so until April. Two to three thousand murres were seen on one of their nesting colonies at Three Arch Rocks off Tillamook County on 16 December 1986 (Roy Lowe, USFWS Biologist, pers. comm.). But the first murres didn't land on their Yaquina Head colony in Lincoln County until early February in 1980 and 1981 (Bayer and Herzing 1985). After they first land on the colony, murre attendance is intermittent. For example, Lowe noted that murres were only sporadically on their Three Arch Rock colony in December 1986. Further, Yaquina Head murres were not frequently on their colony until March 1980 and April 1981 (Bayer and Herzing 1985).

Murre eggs and chicks can be present at Oregon colonies from May through August. Murres at Yaquina Head first started laying eggs in early or late May in 1969-1971 (Scott 1973). At Three Arch Rocks and Cape Lookout, Ferris noted eggs in June, July, and even early August in the 1930's (Bayer and Ferris 1987:105, 107-109).

A murre chick leaves its colony when it is still flightless with an adult male, presumably its father (Scott 1973). The first chick/father pairs were seen near Yaquina Head from June 30 to July 21 in 1969-1971, 1980, and 1982 (Scott 1973, Bayer 1983).

Oregon Coast murre colonies appear to be typically abandoned completely in late July and early August. Off Yaquina Estuary in Lincoln County, Bayer (1985) reported adult murres flying north en masse in late July. By August 3 in 1981, 1983, and 1985, murres had departed the Yaquina Head colony (Bayer, pers. obs.; Lisa Ellingson, pers. comm.), but some murres remained on the Cape Lookout colony in Tillamook County to at least August 13 in 1934 (Bayer and Ferris 1987:108). The exit of murres from Oregon is also confirmed by murre numbers declining dramatically in Yaquina Estuary in August or September of 1975, 1979, 1980, 1982, and 1983 (Bayer 1983, 1986).

After leaving the colony, chick/father pairs swim away. Dan Varoujean (pers. comm.) has indicated that chick/father pairs swim northward after leaving their Oregon colony. However, Bayer (1983) noted that murre chicks showed up at Yaquina Estuary 3.4 miles (5.5 km) south of the Yaquina Head colony on July 10-11 in 1980 and 1982, which was probably long before they could have swum 118 miles (190 km) north from the next colony to the south (Matthews 1983:2). Ferris' 1930-1940 banding data indicate that 7 of 21 chicks (juveniles) recovered in July and August were found south of their nesting colony, and one was found 95 miles (154 km) south of its nesting colony in its first September (Bayer and Ferris 1987:18, 21).

Juvenile murres can move quite far northward. Ferris' banding data indicate that some juveniles arrived in British Columbia waters in September (Bayer and Ferris 1987:18). This supports Manuwal et al.'s (1979:58-59) and Wahl et al.'s (1981:80, 782-783) conjecture that the large increase in Common Murres at the Strait of Juan de Fuca in September may be a result of an influx of murres from at least as far south as Oregon. In their first winter, some juveniles were recovered as far away as near Vancouver, British Columbia (Bayer and Ferris 1987:20-21).

It is not clear when murres start returning to Oregon Coast waters, but they are often present in late December. Ferris' banded murres were not recovered in Oregon from October through December (Bayer and Ferris 1987:18-19), and murres usually were not found in Oregon during winter nearshore or estuarine censuses (Scott 1973, Bayer 1983). But murres were seen near the Oregon Coast in late December and early January during 50-100 per cent of Christmas Bird Counts (CBC) in 1973-1982 at 6 Oregon coastal CBC sites (Bayer and Krabbe 1984). At the Tillamook and Coos Bay CBC sites, an average of 6,733 and 2,720 murres, respectively, were seen on each of 10 CBC's (Bayer and Krabbe 1984).

With the murres' return to the Oregon Coast, their yearly cycle starts again, and they can commence intermittently landing on their colonies.

We are grateful to suggestions made by Paul Sullivan and Owen Schmidt that improved this paper.

Bayer, R. D. 1983. Seasonal occurrences of ten waterbird species at Yaquina Estuary, Oregon. Murrelet 64:78-86.

________. 1985. Nearshore flights of seabirds past Yaquina Estuary, Oregon, during the 1982 and 1983 summers. Western Birds 16:169-173.

________. 1986. Seabirds near an Oregon estuarine salmon hatchery in 1982 and during the 1983 El Nino. Fishery Bull. 84:279-286.

________ and R. W. Ferris. 1987. Reed Ferris' 1930-1943 Bird Banding Records and Bird Observations for Tillamook County, Oregon. Studies in Oregon Ornithology No. 3.

________ and D. L. Herzing. 1985. Pre-laying assemblages of Common Murres on the colony at Yaquina Head, Oregon. Murrelet 66:94-95.

________ and J. Krabbe. 1984. CBC analysis: comparison of [Oregon] coastal Christmas Bird Counts. Oregon Birds 10:115-125.

Manuwal, D. A., T. R. Wahl., S. M. Speich. 1979. The seasonal distribution and abundance of marine bird populations in the Strait of Juan de Fuca and northern Puget Sound in 1978. NOAA Tech. Memo. ERL MESA-44.

Matthews, D. R. 1983. Feeding ecology of the Common Murre, Uria aalge, off the Oregon Coast. M.S. Thesis, Univ. of Oregon, Eugene, Oregon.

Scott, J. M. 1973. Resource allocation in four syntopic species of marine diving birds. Ph.D. Thesis, Oregon State Univ., Corvallis, Oregon.

Wahl, T. R. S. M. Speich, D. A. Manuwal, K. V. Hirsch, and C. Miller. 1981. Marine bird populations of the Strait of Juan de Fuca, Strait of Georgia, and adjacent waters in 1978 and 1979. EPA-600/7-81-156. (Note that this is labeled on the spine as EPA-600/7-80-166.)