Common Birds of Aquatic Areas Near the HMSC Estuary Trail

Final Report for the Hatfield Marine Science Center (HMSC) Volunteers: 26 July 1999. [With Merrifield 2001 and a few minor changes added within brackets in September 2001.]

by Range Bayer

Only species that are apt to be seen by the "average" birder from the HMSC Nature Trail or the road to the HMSC Pump Dock in the Yaquina channel, HMSC Lagoon, and Idaho Flats are included in this list. Rare species are not given nor are terrestrial birds present only in the salt marsh (e.g., Song, Savannah, and White-crowned Sparrows). Note that classifying species as common, uncommon, or rare is often arbitrary and may differ among observers.

The seasonal occurrence and peak count information are for the Yaquina Estuary downstream of Toledo, not for the area only visible from the HMSC Nature Trail. These summaries are cursory and are based largely on Kathy Merrifield's and my published and unpublished research at Yaquina Estuary.

I am grateful to Bob Olson and Kathy Merrifield for commenting on earlier drafts of this report and to Kathy Merrifield, Dave Pitkin, Roy Lowe, and Eric Horvath for graciously providing unpublished data.

See the Reference section at the end for sources of information.

Channel=Yaquina subtidal channel north of the HMSC and north of Idaho Flats.
HMSC Lagoon=embayment north of the HMSC that is bordered on the west by the Wecoma Dock and to the east by the HMSC Pump Dock.
Idaho Flats=embayment adjacent to the HMSC Nature Trail, east of the HMSC. It is within the City Limits of Newport (1991 City Ordinance 1602), so hunting is not legal, although this may not be enforced.
Yaquina=Yaquina Estuary as a whole, not Yaquina Head.

IBA. In October 1998, Yaquina Estuary was recognized as a Continentally Important Bird Area (IBA) by the American Bird Conservancy for Continentally significant numbers of Western Gulls and Nationally significant numbers of Western Grebes, Black Brant, Whimbrels, Sanderlings, Mew Gulls, and Caspian Terns (Gallob 1999). The embayments (including Idaho Flats) are an integral part of the Yaquina Estuary IBA; not included are most areas zoned for development and upstream intertidal areas. The IBA program is a part of the Partners in Flight Bird Conservation Strategy, and Yaquina Estuary and Yaquina Head (which is a Global IBA) are two of only four IBA's designated thus far in Oregon.

Red-throated and Pacific Loons. Uncommon during winter and spring.

Common Loon. Abundant from October through April with a Yaquina peak of 70 during February-April. A few are regularly present in May and September, and straggler nonbreeders, usually immatures, are irregularly present during June-August.

Horned Grebe. Abundant from late September through April with a Yaquina peak of 138. Generally uncommon in May and rare in June-August.

Red-necked Grebe. Uncommon during October-May with a Yaquina peak of 19.

Eared Grebe. 1-3 are uncommon to rare in the channel near the HMSC in winter and spring.

Western Grebe. Most abundant from October through mid-May, with a peak of 600-1,000 grebes during February-March. Rare in June-August, although nonbreeders are often seen along the coast in summer. Uncommon in September. Nationally significant numbers of Western Grebes at Yaquina Estuary were important in the estuary being designated an IBA. If an observer is close enough to a raft of Western Grebes (which do not forage much during the daytime), it is worthwhile to search for the similar Clark's Grebe or intermediate Clark's/Western Grebes that occasionally occur at the Yaquina.

Brown Pelican (Endangered Species). A few are occasionally present in April or May, but usually it is June and generally late August before they become common. Most abundant in September-October with a Yaquina peak of 499 in September 1982, but the yearly peak in 1993 was 79. This variation should not be considered to necessarily represent a downward trend because there is considerable annual variation, and they are very mobile, so that peak numbers during a summer can be easily missed. Common in November- early December and rare thereafter.

Double-crested Cormorant. Most abundant in July-October with a Yaquina peak count 326, but some can be found during the rest of the year. Does not nest in Lincoln County, although they nest elsewhere along the Oregon Coast. This species occurs inland and has come into conflict with fisheries.

Brandt's Cormorant. Usually fewer than 40 are present throughout the year. Nests at Yaquina Head.

Pelagic Cormorant. Generally fewer than 40 occur throughout the year. Nests on the Yaquina Bay Bridge, where Roy Lowe (USFWS) counted 31 nests in 1997, and also at Yaquina Head.

Great Blue Heron. Although present throughout the year, unpublished census data suggest that part of the Yaquina population migrates away in fall. Since herons with feeding territories are present in winter here and territorial herons have been found to be males along the Pacific Coast, it is possible that some or most females are migratory at Yaquina Estuary. Presently, the only known colony is about a mile east of the HMSC, although in some years there have been two colonies near the lower estuary. Numbers peak in summer with the influx of young, and Yaquina peak counts have been of 150-250 herons.
Herons near the HMSC Nature Trail usually have feeding territories, though one has to have at least the patience of a heron to "see" these territories. Territories are large, with an average length of 1,165 ft (355 m), so there may only be 2-3 territorial herons adjacent to the HMSC Nature Trail. A clue that a heron may be territorial is seeing one in the same area day after day, but territorial defense needs to be observed to verify a territory. Territorial defense is expressed in flight chases or displays that can occur less than once per hour. Territorial defense seems most evident from about mid-June to August when recent fledglings arrive at feeding areas and intrude on established territories. The Spread Wings display that has mistakenly been considered to be a courtship dance seems most prevalent between neighboring territorial herons; in this display, the neck is nearly fully extended and tilted slightly over the back, the head and bill are held above the horizontal, the wings are held out from the body, and the displaying heron often walks in a stiff-legged gait that can give a dance-like appearance. About twice per hour, territorial herons emit a simple "song," the Roh-roh-roh Call, that has 2-5 notes with a distinct cadence. (See McMahon 1974, Merrifield 1998, and many of Bayer's papers about Yaquina Great Blue Herons in the References.)

Great Egret. First noted in Lincoln County in 1965. Usually arrive in mid-July or early August, and peak counts of up to 38 for the Yaquina occur in September-October. Rare in the lower estuary after December, but 1-2 were irregularly reported during the 1998 and 1999 nesting seasons, so they may possibly nest, as they do at Coos Bay.

Green Heron. 1-2 can sometimes be seen during late spring and summer on Idaho Flats. In about 1993, a nest was thought to be in the willows east of the HMSC Apartments.

Greater White-fronted Goose. Commonly fly over during spring and fall migration; many flocks migrate west/east across the Coast Range in the Yaquina Bay area (Bayer et al. 1995). Rarely land at Idaho Flats.

Black Brant. Usually arrive the last week of October or early November and are common through May. Brant overwinter at only three Oregon estuaries: Tillamook, Netarts, and Yaquina Bays. Their wintering abundance at these estuaries is only about half of what it was in the early 1980's; now usually only about 150-200 winter at the Yaquina. Peak counts are during spring migration that may start as early as January, with a Yaquina peak of 914 in 1981 and 664 in 1993. Nonbreeders are rare in summer. A pair once nested at Coos Bay, when one of a pair was injured, and its mate remained. Nationally significant numbers of Black Brant at Yaquina Estuary were important in the estuary being designated an IBA.
Along the HMSC Nature Trail, Dave Pitkin (USFWS) has read Brant leg band numbers with a telescope the past few years and determined that Brant return year after year, some arrive in apparent family groups with 1-4 young, and some remain nearly six months, while others are present for a few weeks. The majority of Brant wintering at the Yaquina nest in the Canadian Arctic in the Northwest Territories near Liverpool Bay and Banks Island.

Canada Goose. Non-native Western Canada Geese were introduced by the ODFW into the Florence area in 1983. A few occasionally nest at Yaquina Estuary, and 5-20 are uncommon to rare on the mudflats during winter. But various subspecies of Canada Geese, including the much smaller Cackling and Taverner's Canada Geese, commonly fly overhead during spring and especially fall migration, when many flocks migrate west/east across the Coast Range in the Yaquina Bay area (Bayer et al. 1995).

Green-winged Teal. Uncommon during fall at Idaho Flats.

Mallard. Abundant from August through December with a Yaquina peak of 503 in September. Uncommon the rest of the year. May nest in sloughs of upper estuary.

Northern Pintail. A few often arrive in early August, but they are not abundant until late September. The Yaquina peak of 204 is during November to mid-January, and they are absent after early February. Idaho Flats is their most favored location in the estuary.

Northern Shoveler and Gadwall. Often uncommon during fall-winter, but shovelers can be common during some winters.

American Wigeon. The most abundant surface-feeding duck at the Yaquina. Wigeon first arrive in late August, but they are not abundant until late September. The Yaquina peak period is during late October-January with a peak count of 2,982 in early December during the 1993/1994 winter--peaks in other winters may occur in January. 1-4 male and female Eurasian Wigeon can occasionally be found by diligent searching of nearby flocks of wigeon.

Canvasback. Rare in winter at Idaho Flats, but abundant at upstream embayments.

Greater and Lesser Scaup. Distinguishing between these two species is difficult, especially for distant birds, but Greater Scaup appear to generally be the most common of the two. Both arrive in late September, with a Yaquina peak of 905 during late October through January. A secondary peak of as many as 417 scaup can occur in late March-April, when many participate in feeding at a herring spawn, if available (Bayer 1980a). Common in early May, and some nonbreeding Greater Scaup remain in June in some years.

Long-tailed Duck (formerly Oldsquaw). 1-2 uncommonly seen during winter.

Black Scoter. Uncommon to rare during winter and early spring.

Surf Scoter. Arrive in mid-September and abundant from October through March with a Yaquina peak count of 1,217 in March. Common in April, and a few nonbreeders are occasional during May-August. Surf Scoters are one of the most abundant species present after a spring herring spawn (Bayer 1980a).

White-winged Scoter. Not as abundant as Surf Scoters. Arrive in mid- September and common during October-May with a Yaquina peak count of 57. Rare during June-August.

Common Goldeneye. Uncommon to rare in winter.

Bufflehead. Arrive in October and common from November through early May, with a peak Yaquina count of 1,257. As many as 637 have been counted after a spring herring spawn (Bayer 1980a).

Common Merganser. Probably nests in freshwater areas of the Yaquina River Basin. Females, immatures, and perhaps eclipse-plumaged males appear downstream in the embayments, including Idaho Flats, from mid-September through October, with a peak Yaquina count of 72. They seem to leave the lower estuary at about the time that Red-breasted Mergansers arrive. Common Mergansers are uncommon during the rest of year in the upper estuary.
In winter, female Common Mergansers appear quite different from female Red-breasted Mergansers as is shown in field guides. But in summer, female and immature Common Mergansers look very similar to female Red- breasted Mergansers and can only be distinguished from female Red- breasted's by bill and head shape and nostril position (Kaufman 1990).

Red-breasted Merganser. Uncommon when they arrive in October and abundant during November-early May, with a Yaquina peak of 95. Common in May, and nonbreeding stragglers sometimes occur during June-September, but it is easy to misidentify female Common Mergansers as female Red-breasted Mergansers at this time, so identifications require detailed observations and notes (see Common Mergansers).

Turkey Vulture. During March-September, Turkey Vultures regularly scout Idaho Flats and will land on the mudflats and feed, if carrion is available.

Osprey. Osprey are regular during April-October. Their first nest in Lincoln County was found in 1991, and a nest is often at Mike Miller Park or the South Beach State Park. Historically, DDT was detrimental to their nesting success because it caused thin eggshells, but Osprey have recovered since DDT use in the U.S. was banned.

Bald Eagle. 1-2 adult Bald Eagles and sometimes an immature are often in the Idaho Flats area, especially during low tides in the winter, when they hunt waterfowl and steal fish caught by Great Blue Herons or gulls more often than they catch their own (Bayer 1987). A nest is about a mile east of the Nature Trail, and, formerly, only a single pair of adults nested at the Yaquina; however, during the summer of 1999, two pairs of adults have been present and interacting. Perhaps because of their conflict, neither pair nested. It remains to be seen if one pair will drive the other off, or if both pairs will nest at the Yaquina.

Northern Harrier. Single birds (usually brown females or immatures) are regularly noted from July or August through May; adult males (gray) are uncommon or rare. In recent years, harriers may have nested at South Beach.

Merlin. Singletons are occasionally spotted hunting shorebirds during September-April.

Peregrine Falcon (Endangered Species). Although absent in summer, single Peregrines are most common in October-September. They sometimes perch on the Yaquina Bay Bridge, and there has been some debate about installing a nest box there. But based on experiences elsewhere, the bridge would probably be a bad place for them to nest because swirling winds may force fledglings onto the road surface where they would be killed by passing vehicles.

American Coot. Up to a dozen can be present during fall or winter, especially in the HMSC Lagoon.

Black-bellied Plover. Often common from July through April; most abundant in winter, with a Yaquina peak of 49 in January 1985; however, Black- bellied Plovers seem to be less abundant in winter in recent years. Occasionally present in May.

American Golden-Plover and Pacific Golden-Plover. Uncommon to rare during August-November.

Semipalmated Plover. Can be common during April-May and July-September. Occasionally present in other months.

Killdeer. During prolonged freezing weather, inland Killdeer appear to emigrate to the coast, and they can become common on the mudflats. Otherwise, they are uncommon on Idaho Flats during the year, but they are regularly on the uplands around the HMSC, where they are conspicuous by their calls and where at least one pair regularly nests.

Greater Yellowlegs. Most abundant during April-early May with a Yaquina peak of 30. Uncommon during July-November, and rare in December-March.

Lesser Yellowlegs. Uncommon during spring and fall migration.

Willet. Uncommon during spring and fall migration. In recent years, 1-4 have wintered at the HMSC Lagoon.

Wandering Tattler. During migration, single birds are commonly seen on rocks along the east side of the road going out to the HMSC Pump Dock.

Whimbrel. Arrive in April with a Yaquina peak of 216 in the last week of April or early May. As many as 50 nonbreeders oversummer in June, where they are best seen from the HMSC Nature Trail. Migrants begin arriving the first week of July with as many as 155 counted during July-August 1982. Near dusk, they fly in vociferous flocks from Idaho Flats towards the coast, where they roost. In the 1980's, fewer than 10 wintered, but they have been absent in winter in recent years. Nationally significant numbers of Whimbrels at Yaquina Estuary were important in the estuary being designated an IBA.
Our Whimbrels have head striping that is much less distinct than is shown in some field guides, and bill length can vary amongst Whimbrels. For instance, females have bills that average 13% longer than males, and adults have longer bills than juveniles (Bayer 1994b). Consequently, a Whimbrel with indistinct head striping and a slightly longer bill than others can be misidentified as a Long-billed Curlew, which rarely occur at Idaho Flats.

Marbled Godwit. Often present in April-May, but more likely to be seen during August-October. However, frequency varies from year to year. Rarely winters.

Black Turnstone. Probably fairly common under the Wecoma Dock during fall- spring, but uncommon to rare then on Idaho Flats, where some "turn" algae with their beaks.

Red Knot. Status unclear, but appears to sometimes be common during the peak of small shorebird ("peep") migration in spring. Rare in other months.

Sanderling. Although a few may arrive in late July, they are uncommon until November. Peak abundance is during December-February with a Yaquina peak of 1,090. In terms of days of use by peeps, the Sanderlings' use of the Yaquina is probably much greater than for other peeps because Sanderlings are present longer at high numbers; other peeps are abundant only during a brief migration peak lasting a few days. Nationally significant numbers of Sanderlings at Yaquina Estuary were important in the estuary being designated an IBA.

Western Sandpiper. On about June 24, Western Sandpipers are one of the first arrivals during "fall" migration. Their fall peak abundance is often during August-September, with a Yaquina peak count of 889 in 1993. Unusually, 9,430 peeps that were mostly Western Sandpipers were counted on 9 July 1997 at Idaho Flats by Dave Pitkin (USFWS). Generally fewer than a hundred are counted from October-March.
Western Sandpipers are the most abundant peep during the height of spring migration that occurs during the last week in April and first few days of May, with a Yaquina peak usually fewer than 5,000 at a time. But there is considerable movement of shorebirds to and from the estuary at this time, so that the total number of shorebirds using the estuary is probably considerably greater than any single count. Some Western Sandpipers often linger into late May, so there are often only 2-3 weeks between the time the last one is seen in "spring" and the first "fall" arrival.

Least Sandpiper. During spring and fall migration, they are difficult to distinguish from other peeps, so their seasonal abundance is not clear. Least Sandpipers arrive in early July and are often present thereafter in variable numbers until late May. The Yaquina peak count of 113 was in December, but more may have been present and not identified to species. Thus, they appear to be more similar to Sanderlings in having their peak abundance in winter than to Western Sandpipers, whose peak is during spring and fall migration.

Pectoral Sandpiper. The only place in Yaquina Estuary where Pectorals are regularly reported is along the HMSC Nature Trail. With patience, about a half-dozen Pectorals can be seen in or just below the salt marsh during mid-August through early October.

Dunlin. Although some are present from November through early May, they are most abundant the last week of April during the peak of small shorebird migration with a Yaquina peak count of 560.

Short-billed and Long-billed Dowitchers. Difficult to distinguish. At Idaho Flats, both species are present when they are most abundant during mid-April to early May (Yaquina peak count of 525 in 1985). Scattered dowitchers can also be seen irregularly from July through October in the lower estuary. Long-billeds are sometimes present in winter in the upper estuary or in freshwater.

Common Snipe. Although they used to be regularly found each winter in the salt marsh or just below it near the HMSC Trail, snipe have been rarely seen there during winters in the past decade.

Red-necked and Red Phalaropes. Erratic in abundance and occurrence during spring and fall migration. In May, they can sometimes be very abundant, but, in other springs, they may not be seen at all. A few Red Phalaropes may also appear in winter, especially after a big wind storm.

Bonaparte's Gull. Common during April-May with a Yaquina peak of 40. Usually uncommon in June to mid-July, but in some years as many as 45 nonbreeders have been counted. Fall arrivals begin in late July or early August, with a Yaquina peak of 58 during July-October (and sometimes November). Rare in January-March.

Heermann's Gull. Most common during July-October with a Yaquina peak of 110. Uncommon in November and usually rare from December through May, but Merrifield occasionally found as many as four during February-May 1998. Early migrants sometimes appear in June.

Mew Gull. Although early migrants sometimes arrive in July, Merrifield's unpublished counts show that they are most abundant from October through April, with a peak of fewer than 500. Uncommon in May. Nationally significant numbers of Mew Gulls at Yaquina Estuary were important in the estuary being designated an IBA.

Ring-billed Gull. Stragglers are sometimes present throughout the year, but Merrifield's unpublished censuses indicate that they are most abundant from July or August through October, with a Yaquina peak of fewer than 50.

California Gull. Although some are present every month, Merrifield's unpublished counts indicate that many immigrants arrive in late June. They are most abundant during August-early October, with a Yaquina peak of about 1,500.

Herring and Thayer's Gulls. Merrifield's unpublished censuses reveal that both species are at Idaho Flats. Usually fewer than 20 Herring Gulls are regularly seen during September-May. Thayer's Gulls are difficult to distinguish, especially at a distance, but Merrifield occasionally saw 1-2 during October-February.

Western Gull. Resident throughout the year, but Merrifield's unpublished counts reveal a marked seasonal increase in late June. Western Gulls are most abundant during August-September and sometimes early October, with a Yaquina peak of about 2,000. They can become abundant in spring after herring spawns (Bayer 1980a). In spring and early summer during their nesting season, adults are not common. Continentally significant numbers of Western Gulls at Yaquina Estuary were important in the estuary being designated an IBA.
Although Western Gulls nest more abundantly, earlier, and with greater success at Yaquina Head, many also nest in Yaquina Estuary on navigation markers, pilings, a wooden breakwater, docks, boats, and the Yaquina Bay Bridge (Bayer 1983b). Nests visible from the HMSC Nature Trail include one on the dolphin (circle of pilings cabled together into a single unit) in the middle of the HMSC Lagoon and another on the navigation marker east of the HMSC Pump Dock. Yaquina Estuary Western Gull chicks generally hatch the last week of June and the first week of July. Gulls nesting in Yaquina Estuary generally have low nesting success (average of about 0.6 fledgling/nest)(Bayer 1983b) and have a different social pattern than some, perhaps most, of those nesting along the outer coast . Along the coast, the nesting and feeding areas of gulls can be far apart, so mated pairs may separate during the winter like Spear (1982) describes for Western Gulls near San Francisco. But at the Yaquina, where food is plentiful near nesting areas, a mated pair often remains together throughout the year, and pair bonding (courtship) displays can be seen in winter. This year-around residence of Yaquina Estuary Western Gull pairs makes it more difficult to wean young because the parents can't get away from them, so parental care at the Yaquina can be more prolonged than for parents that separate and fly elsewhere during the winter (Spear et al. 1986). Estuarine gulls may have lower nesting success because they are generally nesting close to edges, so that Western Gull chicks (which are not behaviorally adapted to nest on cliff edges) fall off (especially if disturbed by boaters or other human disturbance) and occasionally are cared for away from the nest.
Western Gulls find cockles or native littleneck clams on or near the mudflat surface but are unable to peck them open, so they drop them on the pavement in the HMSC parking lot or on wet sand to break them open and eat them (Bayer 1984b). Many also feed on herring eggs after a spring spawn (Bayer 1980a).

Glaucous-winged Gull. Merrifield's unpublished counts indicate that Glaucous-winged Gulls are present throughout the year, numbering in the low hundreds, but that adults are rare or absent during the nesting season in spring and early summer. A few interbreed with Western Gulls at Yaquina Head (Hoffman et al. 1978), and, perhaps, also in Yaquina Estuary.

Glaucous Gull. 1-2 are uncommon to rare at Idaho Flats during winter- spring. In spring, Glaucous-winged Gulls with very worn feathers may appear as white as a Glaucous Gull, so plumage color alone is not adequate for identifying Glaucous Gulls.

Caspian Tern. Arrives in late March or early April, and 10-50 nonbreeders often remain in June. Fledged young that are still fed by an adult begin arriving in early July; a fledgling's arrival is apparent by its high- pitched call in response to the hoarse, raspy call of the accompanying adult. Caspians are usually most abundant in July-August, with a peak Yaquina count of 627 in 1983, but more recent peak counts have been about a hundred or less. Usually absent after August. Nationally significant numbers of Caspian Terns at Yaquina Estuary were important in the estuary being designated an IBA.

Common and Arctic Terns. Uncommon to rare during spring and fall migration. Most apt to be seen roosting at Idaho Flats amongst the gulls.

Elegant Tern. First arrived in Lincoln County in 1983, a few can occasionally be found during most summers at Idaho Flats, roosting amongst the gulls and Caspian Terns.

Common Murre. Most common from May through August, with a Yaquina peak in recent years of about 100. Occasional in September, and rare in March- April and October-November. Murres nest at Yaquina Head, and during the last week of June, nonflying chicks that are about 1/4 of adult size jump off colonies and swim off with their fathers. The dependent chick and its father keep in contact by loud calls, and such pairs are often in Yaquina Estuary during July-August. Along the Oregon Coast, many chicks die or become separated each summer and are often brought to places such as the HMSC for care (Bayer et al. 1991).

Pigeon Guillemot. Summer resident that is abundant from March through August with a Yaquina peak of 63; rare the rest of the year. Nests in crevices under the HMSC Pump Dock and elsewhere in Yaquina Bay under docks and, at least formerly, in burrows in sand cliffs at the northeast corner of Yaquina Bay Bridge. The young evidently fledge at night and are very rarely seen in the Yaquina.

Belted Kingfisher. Present during the year, and nests in banks and roadcuts, and, at least in the past, at the eastern end of Idaho Flats. Cursory observations suggest that most kingfishers present in winter are males.

Purple Martin (an Oregon Critical Sensitive Species). A cavity nester in competition with Eurasian Starlings. In the 1970's Tom Lund put up nest boxes on pilings in the upper estuary near Criteser's Moorage. In 1992, one pair nested in a loudspeaker in a pole at the abandoned Oregon Aqua- Foods site, west of the HMSC. Starting in 1993, Eric Horvath has put up many nest boxes, including those that have been used on the dolphin in the middle of the HMSC Lagoon and on pilings out from the HMSC Pump Dock. In 1997, Eric counted 34 pairs nesting at Yaquina Bay.

Barn Swallow. Common during April-September. They sometimes hunt within inches of the mudflats and also will pick up the white feathers of gulls where gulls roost and preen at Idaho Flats to use to line their nests. Often formerly nested on walls at entrances to HMSC, but has rarely done so recently.

American Crow. No Northwestern Crows have been conclusively identified here; crows that look smaller than others may be females (Bayer 1989a). American Crows are present throughout the year and are often overlooked as an important "shorebird." But they often forage on the mudflats, are relatively large, and sometimes number in the hundreds, so their impact on the mudflats may be greater than many shorebird species. Together with gulls, crows often follow human clammers and shrimpers to feed on mudflat creatures brought to the surface. Crows also drop clams on sand or pavement, though they do not seem as adept at this as gulls (Bayer 1984b).

References. Kathy Merrifield's (1998) report is the most complete guide to waterbirds at Yaquina Estuary. [Also see Merrifield 2001.]

Janet Webster and Heather Hiveley of the Guin Library at the HMSC have prepared a complete bibliography about Yaquina Estuary, which is available at Yaquina Bay Bibliography.

Oregon Birders On-Line (OBOL) gives current rare sightings in Oregon as well as links to online information about Oregon birds (including Lincoln County).

Paulson (1993) and Gilligan et al. (1994) are good guides to the birds of Oregon, and Ainley and Boekelheide (1990) have relevant material about nesting seabirds along the California Coast. Sources of general information about North American birds include Terres (1980) and Ehrlich et al. (1988).

Below are papers that I have compiled that are relevant; those specifically for Yaquina Estuary birds are marked with an asterisk (*); Webster and Hiveley may have additional references in their bibliography. The call number at OSU Libraries is given for some papers that may be difficult to find.

*=reference specifically about birds at Yaquina Estuary.

Ainley, D. G. and R. J. Boekelheide (Eds.).  1990.  Seabirds of the 
     Farallon Islands: ecology, dynamics, and structure of an 
     upwelling-system community.  Stanford Univ. Press.  (This is 
     QL684.C2.S44 at OSU Libraries.  In spite of their overlooking some 
     relevant research papers for Oregon seabirds, this book  about the 
     Farallon Islands near San Francisco seems to have the most complete 
     information available for several seabirds that nest along the Oregon 
     Coast, including Brandt's and Pelagic cormorants, Western Gull, Common 
     Murre, Pigeon Guillemot, Rhinoceros Auklet, and Tufted Puffin.)
*Bayer, R. D.  1978.  Aspects of an Oregon estuarine Great Blue Heron 
     population.  Pp. 213-217 in A. Sprunt IV, J. C. Ogden, and S. Winckler 
     (eds.), Wading Birds.  Nat. Aud. Soc. Res. Rep. No. 7.
*Bayer, R. D.  1979a.  Bald Eagle-Great Blue Heron interactions.  Murrelet 
*Bayer, R. D.  1979b.  Great Blue Heron attacks Horned Grebe.  Bird-Banding  
*Bayer, R. D.  1979c.  Intertidal zonation of Zostera marina in the Yaquina 
     Estuary, Oregon.  Syesis 12:147-154.
*Bayer, R. D.  1980a.  Birds feeding on herring eggs at the Yaquina 
     Estuary, Oregon.  Condor 82:193-198.
*Bayer, R. D.  1980b.  Social differences in defecation behavior of Great 
     Blue Herons (Ardea herodias).  Auk 97:900-901.
*Bayer, R. D.  1981a.  Arrival and departure frequencies of Great Blue 
     Herons at two Oregon estuarine colonies.  Auk 98:589-595.
*Bayer, R. D.  1981b.  Great Blue Herons "mousing" in western Oregon.  
     Murrelet 62:91.
*Bayer, R. D.  1981c.  Weights of Great Blue Herons at the Yaquina Estuary, 
     Oregon.  Murrelet 62:18-19.
*Bayer, R. D.  1982a.  Great Blue Heron eggshell thickness at Oregon 
     estuaries.  Wilson Bull. 94:198-201.
*Bayer, R. D.  1982b.  How important are bird colonies as Information 
     Centers?  Auk 99:31-40.  (About Great Blue Herons.)
*Bayer, R. D.  1983a.  Birds associated with California sea lions at 
     Yaquina Estuary, Oregon.  Murrelet 64:48-51.
*Bayer, R. D.  1983b.  Nesting success of Western Gulls at Yaquina Head and 
     on man-made structures in Yaquina Estuary, Oregon.  Murrelet 64:87-91.
*Bayer, R. D.  1983c.  Seasonal occurrences of ten waterbird species at 
     Yaquina Estuary, Oregon.  Murrelet 64:78-86.  (Red-throated and Common 
     Loons, Horned and Western Grebes, Brown Pelican, Great Egret, Brant, 
     Red-breasted Merganser, Common Murre, Pigeon Guillemot.)
*Bayer, R. D.  1984a.  Foraging ground displays of Great Blue Herons at 
     Yaquina Estuary, Oregon.  Colonial Waterbirds 7:45-54.
*Bayer, R. D.  1984b.  Notes on the feeding behavior of gulls and crows on 
     clams and crabs at the Yaquina Estuary, Oregon.  Western Birds 
*Bayer, R. D.  1984c.  Oversummering of Whimbrels, Bonaparte's Gulls, and 
     Caspian Terns at Yaquina Estuary, Oregon.  Murrelet 65:87-90.
*Bayer, R. D.  1984d.  Vocalizations of Great Blue Herons at Yaquina 
     Estuary, Oregon.  Colonial Waterbirds 7:35-44.
*Bayer, R. D.  1985a.  Bill length of herons and egrets as an estimator of 
     prey size.  Colonial Waterbirds 8:104-109.
*Bayer, R. D.  1985b.  Interactions of Great Blue Herons and gulls.  Wilson 
     Bull. 97:538-541.
*Bayer, R. D.  1985c.  Nearshore flights of seabirds past Yaquina Estuary, 
     Oregon, during the 1982 and 1983 summers.  Western Birds 16:169-173.  
*Bayer, R. D.  1985d.  Shiner perch and Pacific staghorn sculpins in 
     Yaquina Estuary, Oregon.  Northwest Science 59:230-240.  (Includes 
     information about perch and sculpins caught by Great Blue Herons.)
*Bayer, R. D.  1986a.  1884-1923 Oregon coast bird notes in Biological 
     Survey files.  Studies in Oregon Ornithology No. 1.  (See p. 16-17, 
     32-33, 35-36, 40.)
*Bayer, R. D.  1986b.  Fledgling Common Murre killed and abandoned by a 
     gull after leaving the vicinity of the colony.  Murrelet 67:30-31.
*Bayer, R. D.  1986c.  Seabirds near an Oregon estuarine salmon hatchery in 
     1982 and during the 1983 El Nino.  Fishery Bulletin 84:279-286.  
     (Brown Pelicans, cormorants sp., gull sp., Caspian Tern, Common Murre, 
     Pigeon Guillemot, Marbled Murrelet.)
*Bayer, R. D.  1987.  Winter observations of Bald Eagles at Yaquina 
     Estuary, Oregon.  Murrelet 68:39-44.
*Bayer, R. D.  1988a.  Changes in waterbird numbers before and after the 
     1983 oil spill at Yaquina Estuary, Oregon.  Oregon Birds 14:157-161.  
*Bayer, R. D.  1988b.  Oiled birds: how to search for and capture oiled 
     birds at Oregon intertidal areas.  Studies in Oregon Ornithology 
     No. 5.  29 pp.  
Bayer, R. D.  1989a.  Are "small" crows along the Oregon Coast necessarily 
     Northwestern Crows?  Oregon Birds 15 (4):277-279.  (In same issue, 
     also see articles starting on p. 279, 281, 285, 286; and 16[3]:223.)
*Bayer, R. D.  1989b.  Effects of solar eclipse on waterbirds at Yaquina 
     Estuary, Oregon.  Oregon Birds 15:198-200.
*Bayer, R. D.  1989c.  The cormorant/fisherman conflict in Tillamook 
     County, Oregon.  Studies in Oregon Ornithology No. 6.  (See p. 68-69 
     for semimonthly maximum numbers of some waterbirds and shorebirds at 
     Yaquina Estuary.)
*Bayer, R. D.  1993.  Waterbird records for West and East Ponds, South 
     Beach Peninsula, Lincoln County.  Journal of Oregon Ornithology 
*Bayer, R. D.  1994a.  Harlequin Duck records mostly from Lincoln County, 
     Oregon.  Journal of Oregon Ornithology 3:243-260.
Bayer, R. D. 1994b.  Identifying Long-billed Curlews along the Oregon 
     Coast: a caution.  Oregon Birds 20(4):121-122.
*Bayer, R. D.  1996a.  Censuses of Black Brant at Yaquina Estuary, Lincoln 
     County, Oregon.  Journal of Oregon Ornithology 6:723-780.
*Bayer, R. D.  1996b.  Transcription of Vernon Bailey's field notes for his 
     1909 trip to Lincoln Co., Coos Co., and Curry Co., Oregon with notes 
     about Biological Survey records.  Journal of Oregon Ornithology 
*Bayer, R. D. and J. Krabbe.  1984.  CBC analysis: comparison of coastal 
     Christmas Bird Counts.  Oregon Birds 10:115-125.
*Bayer, R. D., R. W. Lowe, and D. Faxon.  1995.  Spring and fall migration 
     of geese across the Coast Range of Lincoln Co., Oregon.  Oregon Birds 
Bayer, R. D., R. W. Lowe, and R. E. Loeffel.  1991.  Persistent summer 
     mortalities of Common Murres along the Oregon Central Coast.  Condor 
*Bayer, R. D. and E. McMahon.  1981.  Colony sizes and hatching synchrony 
     of Great Blue Herons in coastal Oregon.  Murrelet 62:73-79.
*Braly, J. C.  1938.  Occurrence of the Marbled Godwit on the coast of 
     Oregon.  Condor 40:88-89.
*Broadbrooks, H. E.  1946.  Anthony Green Heron at Yaquina Bay, Oregon.  
     Murrelet 27:12.
*Courtney, E. W.  1988.  Dunlins and Sanderlings under the winds of Yaquina 
     [Estuary]: a philosophical treatise.  Sanderling Press, Corvallis, 
     Oregon.  (His personal, non-ornithological impressions of waterbirds 
     at Yaquina Estuary.)  
Ehrlich, P. R., D. S. Dobkin, and D. Wheye.  1988.  The birder's handbook.  
     Simon & Schuster, New York.
*Einarsen, A. S.  1965.  Black Brant: sea goose of the Pacific Coast.  
     Univ. Washington Press, Seattle.
*Faxon, D.  1987.  Immature Bald Eagle captures gull.  Oregon Birds 13:34.
*Gabrielson, I. N.  1934.  Some Oregon specimens worthy of record.  
     Murrelet 15:25.
*Gabrielson, I. N. and S. G. Jewett.  1940.  Birds of Oregon.  Oregon State 
     Monogr., Studies in Zoology No. 2.  (Reprinted in 1970 by Dover 
     Publications as "Birds of the Pacific Northwest."  Lots of skimming is 
     required to find Yaquina Bay records, many of which were published 
*Gallob, J.  1999.  Yaquina Bay recognized as 'Continentally Important Bird 
     Area.'  P. A2 in January 27 Newport News-Times (newspaper).  Newport, 
     Oregon.  (This contains several inaccuracies.)
*Gerow, J.  1939.  Bald Eagle kills Black Brant.  Murrelet 20:44. 
Gilligan, J., M. Smith, D. Rogers, and A. Contreras.  1994.  Birds of 
     Oregon: status and distribution.  Cinclus Publications, McMinnville, 
*Henny, C. J.  1967.  Population characteristics of the Dusky Canada Goose 
     as determined from banding data.  M.S. Thesis, Oregon State Univ., 
*Henny, C. J. and J. A. Collins.  1980.  Early concentrations of Brown 
     Pelicans along southern Oregon Coast.  Murrelet 61:99-100.
*Hoffman, W. and W. P. Elliott.  1974.  Occurrence of intergrade Brant in 
     Oregon.  Western Birds 5:91-93.
Hoffman, W., J. A. Wiens, and J. M. Scott.  1978.  Hybridization between 
     gulls (Larus glaucescens and L. occidentalis) in the Pacific 
     Northwest.  Auk 95:441-458.
Kaufman, K.  1990.  The practiced eye: Common Merganser and Red-breasted 
     Merganser.  Am. Birds 44:1203-1205.
*Matthews, D. R.  1983.  Feeding ecology of the Common Murre, Uria aalge, 
     off the Oregon Coast.  M.S. Thesis, Univ. of Oregon, Eugene.
*McMahon, E.  1974.  A survey of Great Blue Heron rookeries on the Oregon 
     coast.  NSF Student-Originated-Studies Project, Univ. Oregon, Eugene.  
     (This is QL696.C52 S9 at OSU Libraries.)
*Merrifield, K.  1998.  Waterbird censuses of Yaquina Bay, Oregon: March 
     1993-February 1994.  Oregon Department of Fish and Wildlife, Wildlife 
     Diversity Program.  Tech. Report 98-1-01.  (This is QL684.06 M471 1998 
     at OSU Libraries; a copy may be available upon request from ODFW, P.O. 
     Box 59, Portland, OR 97207.)
[*Merrifield, K.  2001.  Larid, alcid and crow censuses of Yaquina Bay, 
     Oregon: June 1997-June 1999.  Oregon Department of Fish and Wildlife, 
     Wildlife Diversity Program.  Tech. Report 01-05.]  
*Nehls, H.  1987.  Oregon's first Ross' Gull.  Oregon Birds 13:286-291.
*Page, G. W., W. D. Shuford, J. E. Kjelmyr, and L. E. Stenzel.  1992.  
     Shorebird numbers in wetlands of the Pacific Flyway: a summary of 
     counts from April 1988 to January 1992.  Point Reyes Bird Observatory, 
     Stinson Beach, California.
Paulson, D.  1993.  Shorebirds of the Pacific Northwest.  Univ. of 
     Washington Press, Seattle.
*Scott, J. M.  1973.  Resource allocation in four syntopic species of 
     marine diving birds.  Ph.D. Thesis, Oregon State Univ., Corvallis.
*Scott, J. M. and T. W. Haislip, Jr.  1969.  An Oregon record of the 
     Emperor Goose.  Murrelet 50:38.
*Shaw, W. T.  1924.  The Sabine Gull in Oregon and on the lower Yukon.  
     Condor 26:108.
Spear, L.  1982.  Dispersal patterns of Farallon Western Gulls.  Point 
     Reyes Bird Observatory Newsletter 60:1-3, 10-11.  (This is 
     QL684.C2.P61 at OSU Libraries.)
*Spear, L. B., D. G. Ainley, and R. P. Henderson.  1986.  Post-fledging 
     parental care in the Western Gull.  Condor 88:194-199.
*Sutherland, G. B.  1982.  A plan for protecting the natural resources of 
     Yaquina Bay, Oregon from oil spills.  Oregon Dept. of Environmental 
     Quality.  (This is TD427.P4 at OSU Libraries.)
Terres, J. K.  1980.  Encyclopedia of North American birds.  Alfred A. 
     Knopf, New York.
*USFWS (U. S. Fish and Wildlife Service).  1968.  Fish and wildlife of 
     Yaquina Bay, Oregon: preliminary survey of fish and wildlife in 
     relation to the ecological and biological aspects of Yaquina Bay, 
     Oregon.  U.S. Dept. of Interior, Fish and Wildlife Service.  (This is 
     QL84.22.O6 U51 at OSU Libraries.)
*Wetzel, D.  1996.  Brant use of Yaquina Estuary, Lincoln County, Oregon in 
     the spring of 1976.  Journal of Oregon Ornithology 6:715-722.
*Woodcock, A. R.  1902.  Annotated list of the birds of Oregon.  Oregon 
     State University, Oregon Agric. Exper. Station No. 68.

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