Bird Trends

Evaluation: Some Action Needed/Closely Monitor

Greg Gillson, http://thebirdguide.com/

Issue Summary:

In general, local bird populations, a potential indicator of local habitat and climate change, appear to be stable. There are indications that over the past 38 years several species have shifted their ranges and population densities but more research is necessary to verify these apparent trends and to interpret what they mean.

Why do we care:

Changes in local bird populations can signal important changes in habitat abundance or suitability that may affect birds and other wildlife. Changes in bird presence and timing of migration can be early indicators of habitat change or other species shifts (e.g., prey species, vegetation for cover/forage).

WHAT’S HAPPENING?

Christmas Bird Count (CBC) 38 yr. Data Summary

Christmas Bird Count (CBC) surveys have been conducted in Coos County since 1972 and 38 years of data are available for analysis. Because of the anecdotal quality of these data (see below), we validated the results of our analyses with local bird experts who have participated in the CBC for many years.

Cape Arago Audubon Society Coos Bay Christmas Bird Count.
Circle and numbered citizen science bird survey areas

It should be noted that not all years are complete (there are two years when the CBC survey did not get done). The protocol for CBC bird surveys includes a varying number of surveyors with varying bird surveying skills surveying a portion of a 15 mile diameter circle.

Conclusions derived from these data required validation by local bird experts/advisors because the local CBC has been conducted under the guidance of different compilers. The current compiler assumed responsibility for the count in 1998 and since then the CBC count has surpassed 150 species every year (only surpassed once before 1998). The difference is attributed to improved pre-CBC area site scouting, recruiting skilled birders, and improving birding team organization. Because of this improved organization and scouting, birds that could have been present for the last 30 years but were missed because of a lack of birding experience by CBC participants, may look to be more common than they actually are. As noted above, local bird experts commented on and corrected conclusions we initially drew from the data.

 

Species Arrivals (Table 1)

Are there bird species once not seen here that are now routinely showing up on the Christmas Bird Count list?

 

  • The American Pipit (Anthus rubescens) has been sighted in low numbers nearly every year since its first sighting in 1976 (T. Rodenkirk, personal communication, January 19, 2012).

 

  • The Band-tailed Pigeon (Patagioenas fasciata) was sighted three years in the mid-80s, then again six years from 1998-2009. T. Rodenkirk (personal communication, January 19, 2012) noted that it is very rare in winter.

 

  • Presence of Barred Owls (Strix varia) is increasing in Coos County (R. Smith, personal communication, May 3, 2012)

 

  • Black Phoebes (Sayornis nigricans) have been sighted every year since 1996 but not before. T. Rodenkirk (personal communication, January 19, 2012) noted that Black Phoebe has been “expanding its range like crazy in the past 20 years” and now breeds as far north as Portland and Tillamook.

 

  • Eurasian Collared Dove (Streptopelia decaocto) have been increasingly common since first sighting in 2007 and their numbers “have exploded,” (T. Rodenkirk, personal communication, January 19, 2012).

 

  • Ospreys (Pandion haliaetus) have been sighted during every year since 1997 but not before and one to three now winter annually (T. Rodenkirk, personal communication, January 19, 2012).

 

  • Common Yellowthroat (Geothlypis trichas) has been sighted five times since 2002 but not before. It is now “found overwintering almost annually in the county in one or two locations” (T. Rodenkirk, personal communication, January 19, 2012).

 

  • Cedar Waxwings (Bombycilla cedrorum) weren’t sighted between 1984 and 1998, but were regularly seen before and after. This species was also seen in 1988 and 1989.

 

  • Northern Fulmars (Fulmarus glacialis) were sighted rarely before 1980 (two of seven years) and occasionally since 1997 (seven of 13 years), but not in the intervening years.

 

      • Swamp Sparrows (Melospiza georgiana) were sighted rarely prior to 1996, but have been seen each year since. “This is due to having skilled birders on the count as swamp sparrows are often only identified by call, and are often overlooked by less experienced observers. (T. Rodenkirk, personal communication, January 19, 2012).

 

    • Whimbrel (Numenius phaeopus) has not been seen since 1982.  T. Rodenkirk (personal communication, January 19, 2012) speculated that early observers may have confused this species with Long-billed Curlew which is more regularly seen although in small numbers.

 

      • Brant (Branta bernicla) have not been seen since 2007 though they were sighted most of the previous years and “one were seen from 1983 through 1989,” (T. Rodenkirk, personal communication, January 19, 2012).

 

        • Tundra Swans (Cygnus columbianus) were seen routinely until 1995, and have only been sighted twice since.

 

      • Cattle Egret (Bubulcus ibis) was seen nearly every year until 1986 and not since. Formerly rapidly expanded range in the 70’s and 80’s, then decreased significantly (T. Rodenkirk, personal communication, January 19, 2012).

Table 1.  Bird species “arrivals” to Coos County over the past 38 years.

Table 2. Bird species “departures” from Coos County over the past 38 years.

Species population trends (Table 3)   Are there any species population trends that stand out?

 

  • Brown Pelican (Pelecanus occidentalis) sightings since 2003 have increased dramatically.

 

  • Canada Goose (Branta canadensis) sightings have steadily increased over the survey, from less than one per hour before 1991 to more than eight per hour in 2010. T. Rodenkirk (personal communication, January 19, 2012) noted that the first record was in 1976 when they were reintroduced; “double digit numbers started in 1984 and have increased ever since.”

 

  • Canvasbacks (Aythya valisineria) have been sighted a lot less frequently since 1992, though they have been seen every year.

 

  • Greater White-fronted Geese (Anser albifrons) were seen rarely before 2001, and sightings increased rapidly in the last two years.

 

  • Harlequin Ducks (Histrionicus histrionicus) have been seen in most years, but sightings in the last three years have been the highest three totals for the Coos Bay CBC.

 

  • Mallard Ducks (Anas platyrhynchos) have been seen every year, and sightings have increased over time.

 

  • Redheads (Aythya americana) have not been seen every year, and sightings have decreased over time.

 

  • Red-winged Blackbirds (Agelaius phoeniceus) have been seen in most years, and are becoming more common.

 

  • Anna’s Hummingbird (Calypte anna) has been seen most years of the survey, and sightings have been increasing over time.

 

  • Golden-crowned Sparrows (Zonotrichia atricapilla) are seen every year, and have been sighted more frequently over time.

 

Table 3.  Bird species population trends that stand out in Coos County over the past 38 years.

North American Breeding Bird Survey (BBS) BackgroundThe North American Breeding Bird Survey (BBS) is a long-term, large-scale, international avian monitoring program initiated in 1966 to track the status and trends of North American bird populations. Unlike the Christmas Bird Count that censuses non-breeding birds, the BBS serves to census breeding birds during the onset of nesting season for the majority of species.

North American Breeding Bird Survey (BBS) 13 yr. Data Summary
The closest BBS route to Coos Bay is Oregon route #117 (Glasgow), located on the northeast side of the bay in the Glasgow community. The Glasgow BBS has a cumulative breeding species list of 98 different birds. Data for this site has been inconsistently collected as the route was started in 1986 and ran until 1990, then again from 1994 to 1996, then in 2005, and then from 2008 until 2011 (Appendix A). However, since data has been collected for multiple consecutive years during the last 3 decades, one can glean a few insights into bird population trends in this area of Coos Bay.

Data is almost exclusively recorded from auditory observations. Thus, those observers with better “birding by ear” skills might have recorded more species and more individuals than less skilled observers. This, rather than or possibly in addition to habitat alteration, may be a better explanation of some of the data anomalies such spiked increases for Pacific-slope Flycatcher, Warbling Vireo and Wilson’s Warbler seen in the mid-90’s data (Graph 1).

Graph 1: Unusual spiked increase in individual detections in 3 different passerines in Glasgow BBS

North American Breeding Bird Survey (BBS) (Graph 2)Besides these anomalies, one can see a significant increase in the local populations of Canada Goose, Great Egret (Ardea alba), Turkey Vulture (Cathartes aura) and Steller’s Jay (Cyanocitta stelleri). Through natural pioneering and transplant programs, resident “Western” Canada Geese populations have been steadily increasing over the last 3 decades in coastal Oregon (Subcommittee on Pacific Population of Western Canada Geese, 2000) and introduced populations have been present in Coos County since at least 1976 (Rodenkirk, unpublished manuscript). Great Egrets have increased in the county (Rodenkirk, unpublished manuscript) and have a significant breeding rookery near the junction of Catching Slough and Coos River. They often feed at lower tides in Haynes Inlet. Turkey Vultures are scavengers and nest on the ground, usually in fallen log or hollow stump. Vulture populations appear to be experiencing major increases throughout the United States (Avery, 2004). Steller’s Jays are opportunistic foragers and supplemental food sources, such as bird feeders, may assist in successful breeding and range expansion.

Graph 2: Significant bird population increases in Glasgow BBS

Other bird species that have shown slight detection increases include Osprey, Bald Eagle (Haliaeetus leucocephalus), Eurasian Collared-Dove, Mourning Dove (Zenaida macroura) and Vaux’s Swift (Chaetura vauxi). Osprey and especially Bald Eagle populations have increased in the lower 48 due to the ban of certain pesticides, specifically the 1972 ban of DDT. An unusually large jump in Vaux’s Swift in 2011 might be due to weather conditions. Swifts are aerial insectivores and forage at varying heights, depending on weather conditions for flying insects. Vaux’s Swifts typically nest in large, hollow snags, but will utilize human structures, especially chimneys. Swifts can often seen foraging flocks of swifts far from suitable nesting habitat (R. Namitz, personal observation).

Interestingly, both the number of bird species and the individuals detected have increased over the past 3 decades (Graph 3, Graph 4). Increased observer skills and an increase in “edge tolerant” bird species due to rural development may have both contributed to these increases.

Graph 3: Slight increase in the number of bird species detected on Glasgow BBS

Graph 4: Slight increase in the number of individual birds detected on Glasgow BBS

North American Breeding Bird Survey (BBS) Population Decreases (Graph 5)Curiously, 2 species were not recorded in the last 5 years (i.e. 2000’s) though present in the previous 2 decades. Most unusual is the disappearance of the Cliff Swallow (Petrochelidon pyrrhonota), an insectivore that readily uses man-made structures to nest. Cassin’s Vireos (Vireo cassinii) are mainly found away from the coastal plain in Coos County in mixed deciduous-conifer habitats (Rodenkirk, unpublished manuscript). It is unclear why these two species are no longer present.

Graph 5: Significant bird population decreases in Glasgow BBS

Miscellaneous Bird Report Findings and Population Trends

Purple Martin Distribution and Abundance
The Purple Martin (Progne subis) is on the Oregon Department of Fish and Wildlife’s (ODFW) Sensitive Species List under the category of Critical (Horvath, 1999). This list is reviewed and updated every two years. The Western Purple Martin Working Group has identified three main factors contributing to the decline of western populations of Purple Martin:
 Habitat loss has resulted from coastal lowland urban and agricultural development;
 Forest management and fire suppression have reduced the availability of large snags for nesting use;
 Introduction and proliferation of the European Starling (Sturnus vulgaris) and House Sparrow (Passer domesticus) have increased competition for a dwindling supply of natural nest cavities (Western Purple Martin Working Group, 2012).

T. Rodenkirk (personal communication, August 16, 2012) noted that since the Bureau of Land Management (BLM) has not practiced clearcutting in about 20 years, “there is virtually no federal lands on the south [Oregon] coast with snag-nesting PUMA [Purple Martin], they are practically solely on private.” T. Rodenkirk (personal communication, August 16, 2012) also stated that “since most private companies leave few or no snags, PUMA [Purple Martins] still have very little habitat to occupy but they are starting to make nests in roads [cut banks].” Purple Martin populations have increased in the Coos Bay area due to an artificial nest box project started in 1998 by Eric Horvath and Tim Rodenkirk (Rodenkirk, unpublished manuscript).

Bald Eagle Distribution and Abundance
On August 9, 2007, the Bald Eagle (Haliaeetus leucocephalus) was taken of the U.S. Fish and Wildlife Service’s (USFWS) federal list of threatened and endangered species. A thirty year report (1987-2007) on Bald Eagles nesting in Oregon supported this delisting, citing an average 7.3% increase in population per year (Isaacs and Anthony, 2011). This data was consistent on the local scale with an increase of nests seen in the Coos County with 4 new nesting territories established since 2000 (Isaacs and Anthony, 2008). “They are definitely on the increase,” (J. Heaney, personal communication, August 16, 2012). J. Heaney (personal communication, August 16, 2012) also noted that local populations of Peregrine Falcons (Falco peregrinus) have increased as well.

Other valuable bird surveys
Although data is available, there were a number of other bird surveys not included in this report due to the inconsistent and/or non-scientific nature of data collection (R. Namitz, personal observation). These include, but are not limited to, the North American Migration Count (NAMC), Secretive Marsh Bird Surveys and the Coos Winter Raptor Survey. With more time and standardized data collection methods, these surveys could be of use in the future to assist in determining local bird population trends.

SUMMARY OVERVIEW
Overall, resident bird populations appear to be stable with a few species increasing and few species decreasing. Due to herculean efforts of volunteers and professional alike, Peregrine Falcons, Bald Eagles and Brown Pelicans became national success stories as populations increased enough to merit delisting from the federal Threatened and Endangered Species List in 1999, 2007 and 2009, respectively. Another tentative success story is the coastal population of Snowy Plover (Charadrius nivosus), a state and federal Threatened species that has been increasing over the last 20 years (Lauten, Castelein, Farrar, Kotaich & Gaines, 2010) due to intense human management and predator control. These are clear-cut examples where human management and protection saved an animal species from continuing down the perilous road to extinction.

The largest reason for a bird to expand its range is to draw greater resources. Human causes such as changing of habitat and global climate change are also leading factors in avian range expansion (Askins, 2000). Black Phoebes and Red-shouldered Hawks (Buteo lineatus), two species that used to be restricted to extreme southwestern Oregon, have expanded their breeding ranges in the last 30 years north to at least Tillamook County and east to the Willamette Valley with vagrants showing up in central and southeastern Oregon (R. Namitz and T. Rodenkirk, personal observation). A combination of the above factors may have influenced these range expansions. Black Phoebes have also expanded their range north into Utah and Colorado from the Southwest (Faulkner, Dexter, Levad & Leukering, 2005).
Human population growth and urban have benefitted a number of birds species, some native and some introduced. “The expansion of human activities into rural areas and natural landscapes has resulted in widespread increases in the abundance of synanthropic species that threaten rarer native species,” (Peery & Henry, 2010). As was aforementioned, Avery (2004) notes that Turkey Vultures are increasing. American Crows (Corvus brachyrhynchos) and Common Ravens (Corvus corax) are known to have greater densities in urban/suburban areas than rural areas (Kelly, Etienne, & Roth, 2002). Introduced European Starlings and House Sparrow thrive in urban areas, yet are not readily found in rural areas (R. Namitz, personal observation). Eurasian Collared-Dove, another introduced species exclusively found in urban areas, was first recorded in Oregon in 1999. By 2006, breeding had been established in all 36 Oregon counties including Coos (R. Namitz & T. Rodenkirk, personal observation). Although there is concern of competition with a native urban columbid, the Mourning Dove, Poling and Hayslette (2006) found that although there is dietary overlap between the two species, the Eurasian Collared-Dove “does not appear behaviorally more aggressive or competitively successful than Mourning Doves.”

Though it can be very difficult to assess and assign global climate change, there are two instances that come to mind in regards to birds in coastal Coos County. The Pacific coast population of Brown Pelican breeds from southern California down to Chile, with peak egg-laying in California occurring from March to May (Department of the Interior, U.S. Fish and Wildlife Service, 2009). Post-breeding birds move north along the Pacific coast to exploit the summer upwelling phenomenon and start arriving in late April. By summer time, thousands of Brown Pelicans have arrived in Oregon. Most return south by November, but increasing numbers of pelicans are remaining through the winter, especially within the last three years (R. Namitz & T. Rodenkirk, personal observation). In the winter of 2009-2010, thousands of birds lingered in Oregon through December feeding on a late abundance of bait fish, and unfortunately, hundreds died a month later when downwelling swept the food supply out to deeper water. USFWS biologist Roy Lowe (Terry, 2010) suspected that a change in ocean food supply due to a shifting ecosystem caused the pelicans to stay later and predicts more of the same for the future.

Another possible phenomenon partially explained by global climate change is the increase in wintering Neotropical migrants in Coos County. Neotropical migrants are birds that summer in the northern temperate and polar latitudes, using rich, ephemeral food sources to nest and reproduce. They migrate south in the winter to the tropics where climate and food are agreeably constant and cycle northward the following spring. Orange-crowned Warblers (Oreothlypis celata) and Common Yellowthroats (Geothlypis trichas) are annual residents, albeit in very small numbers, in Coos County during the winter (T. Rodenkirk, personal communication). A Yellow-breasted Chat (Icteria virens) was found wintering at a local bird feeder in Coos Bay in 2012, a first winter record for Oregon. Although, there is anecdotal evidence to suggest the number of wintering Neotropical migrants is increasing in Oregon, more data-sifting is necessary.

Estuaries deliver invaluable ecosystem services that are “fundamental life-support processes upon which all organisms depend,” (Daily et al., 1997). Coos Bay is the second largest estuary in Oregon (Cortwright, Weber & Bailey, 1987), comprising an area of approximately 13,350 acres. Hoffnagle ad Olson (1974) estimate that 90% of the salt marshes of this estuary have been diked or filled to accommodate expansion of industry or residential areas and for agriculture and for dredged material disposal sites. This destruction of valuable habitat may have negatively affected several bird species. Brant have one of the most specialized diets of all goose species and feed preferentially on intertidal (or shallow subtidal) eelgrass (Zostera spp.) from autumn through late spring (Krapu & Reinecke, 1992). Brant winter in significant numbers to the north and south of Coos Bay (Pacific Flyway Council, 2002), but do not utilize the Coos Bay estuary except in spring where numbers peak in April (T. Rodenkirk, unpublished manuscript). The Coos estuary is an important migration stop-over location for Brant to feed and refuel for the northbound journey, but it is unclear why the area does not provide suitable conditions for a wintering population. Bales (personal communication, August 23, 2012) suggested a number of factors may be in play including the smaller size of Oregon’s bays in relation to the entire Pacific coast, the amount of human disturbance involved at these bays and the extent of eelgrass beds available. He also noted that the distribution of wintering Brant has changed in recent years with many birds remaining in Alaska to winter in Izembek Lagoon while another large portion of the population winters in Mexico. Global climate change is suspect in allowing a significant portion of the Brant population to remain wintering in Alaska.

Shorebirds use the Coos estuary in winter and during migration. Foraging flocks tend to be localized around the bay (R. Namitz & T. Rodenkirk, personal observation) probably due to a number of factors including distinct patches of invertebrate productivity, exposed mudflat availability and human disturbance. Shorebird conservation as a whole is a high priority world-wide because a large proportion of shorebird species is in decline. High-tide roost availability is an important aspect of wintering and migration stop-over locations. Human disturbance is a leading factor in determining high-tide roost locations (Peters & Otis, 2007). The Coos estuary receives frequent recreational use through fishing, crabbing, shellfish harvesting, ATV riding, camping, hiking, horseback riding and others. One of the best known high-tide roosts for the last 20 years has been located on the North Spit of Coos Bay on the deflation plain that was a site for an effluent holding pond for a Weyerhaeuser pulp mill. Natural succession has reclaimed the site after closure of the mill and the site is decreasing rapidly as a high-tide roost for shorebirds. Cape Arago Audubon Society is seeking to work with the current owner of this land, the Port of Coos Bay, in a habitat management plan that would support features necessary for a successful high-tide roost.

Two state and federally threatened species, the Marbled Murrelet and the Spotted Owl, are declining not only locally, but throughout the Pacific Northwest in the Lower 48 (Lynch, Roberts, Falxa, Bown, Tuerler, & D’Elia, 2009; Courtney et al., 2004). Both of these species prefer old-growth coniferous or mixed coniferous forests and have declined mostly due to timber harvest practices and, on federal lands, fire (Lynch, Roberts, Falxa, Bown, Tuerler, & D’Elia, 2009; Courtney et al., 2004). The highly competitive Barred Owl has also had a detrimental effect on Spotted Owl reproductive success (Courtney et al., 2004).

Another guild of birds that has not benefitted from timber harvest practices is the woodpeckers. Woodpecker populations in Coos County do not appear to be declining (R. Namitz & T. Rodenkirk, personal observation) although more study is needed. It is presumed, however, that if snags had been left on managed private and federal lands than woodpeckers, and hence those bird species that depend on woodpecker holes for nest cavities, would have more robust populations. Most notably, standing snags and accompanying woodpecker cavities would benefit Purple Martins and Western Bluebirds (Sialia mexicana), but a plethora of other bird species (and a few mammal species) have been known to use woodpecker cavities including chickadees, swallows, wrens, nuthatches, other woodpeckers, Wood Duck, small owls and small falcons (Scott, Evans, Patton & Stone, 1977).

It appears that the two most influential factors to Coos County bird populations are habitat degradation and human disturbance. Timber harvest practices continue to aide in the decline of threatened species and assist the spread of synanthropic bird species that threaten these rarer species. Human disturbance and recreational use have a negative impact of many bird species, especially migrating shorebirds and waterfowl, as crucial activities of feeding and resting are constantly interrupted. Global climate change has certainly influenced certain species (e.g. assisting in range expansion), but does not appear to be solely responsible to any one population trend.

Audubon Society’s Annual Christmas Bird Count (CBC)
The Audubon Society’s annual Christmas Bird Count (CBC) was started as a census of non-breeding birds. It does not characterize or attempt to characterize the condition or quality of an area to support breeding species. By design the CBC dramatically under represents or totally overlooks many species of neo-tropical migrant species such as warblers.

The status of breeding birds in the Coos Bay area is not well understood. For example, even if CBC’s report occasional sightings of a species like Marbled Murrelet (Brachyramphus marmoratus) or Spotted Owl (Strix occidentalis), a mid-winter occurrence says nothing about the suitability of the area for nesting. The South Slough and Coastal Frontal watersheds area are essential stop-over locations for highly migratory species (e.g. Brant, Western Sandpiper). Other species (e.g. Pacific Loon) may be observed in the South Slough and Coastal Frontal watersheds area in huge numbers while en route to breeding areas, but may not rely on conditions of our area that much.

As a next step, it will be important to begin to associate various ecological services in the South Slough and Coastal Frontal watersheds with different individual bird species or species clusters. For example, most species of shorebirds use wetlands in the South Slough and Coastal Frontal watersheds area as essential feeding areas and staging areas in winter and during migration, but few species of shorebirds nest here. Other species rely on the habitats of this area year round (such as kinglets and chickadees). Still other species or guilds of species rely on this area as a summer breeding site (e.g. Wilson’s Warbler, Orange-crowned Warbler, Swainson’s Thrush). These “summer only” species are not represented in the CBC data. Finally, other species (all of whom will have been captured by the CBC data) occur here only in winter (e.g. Varied Thrush).

North American Breeding Bird Survey (BBS)
The North American Breeding Bird Survey (BBS) is a long-term, large-scale, international avian monitoring program initiated in 1966 to track the status and trends of North American bird populations. Unlike the Christmas Bird Count that censuses non-breeding birds, the BBS serves to census breeding birds during the onset of nesting season for the majority of species.

References

Askins R. A. (2000). Restoring North America’s Birds: Lessons from Landscape Ecology. Yale
University Press. New Haven and London.

Avery, Michael L. (2004). Trends in North American Vulture Populations.
USDA National Wildlife Research Center – Staff Publications. Paper 5
http://digitalcommons.unl.eduicwdm_usdanwrc/75

Cortwright R., Weber J. & Bailey R. (1987). The Oregon Estuary Plan Book. Oregon Department
of Land Conservation and Development, Salem, Oregon.

Courtney, S.P., Blakesley, J.A., Bigley, R.E., Cody, M.L., Dumbacher, J.P., Fleischer, R.C., . . .
Sztukowski, L. (2004). Scientific evaluation of the status of the Northern Spotted Owl. Sustainable Ecosystems Institute. Retrieved from http://www.sei.org.

Daily, G.C., Alexander, S., Ehrlich, P.R., Goulder, L., Lubchenco, J., Matson, P.A., . . . Woodwell,
G.M. (1997). Ecosystem Services: Benefits Supplied to Human Societies by Natural Ecosystems. Issues in Ecology, 2. Ecological Society of America. Retrieved from http://www.esa.org

Department of the Interior, U.S. Fish and Wildlife Service. (2009). Brown Pelican Pelecanus
occidentalis. Retrieved from http://www.fws.gov

Faulkner, D., Dexter C., Levad, R. & Leukering, T. (2005).Black Phoebe Breeding Range
Expansion Into Colorado. Western Birds 36, 114-120.

Hoffnagle, J., & Olson, R. (1974). The salt marshes of the Coos Bay Estuary.
Port of Coos Bay Community and University of Oregon. Oregon Institute of Marine Biology, Charleston. p86. Retrieved from https://scholarsbank.uoregon.edu

Horvath, E. (1999). Distribution, abundance, and nest site characteristics of Purple Martins in
Oregon. Technical Report #99-1-01. Oregon Department of Fish and Wildlife, Wildlife Diversity Program, p143.

Isaacs, F.B., & Anthony, R.G. (2008). Bald eagle nest locations and history of
use in Oregon and the Washington portion of the Columbia River Recovery Zone,
1971 through 2007. Oregon Cooperative Fish and Wildlife Research Unit,
Oregon State University, Corvallis, Oregon, USA.

Isaacs, F. B., & Anthony, R.G. (2011). Bald eagles (Haliaeetus leucocephalus) nesting
in Oregon and along the lower Columbia River, 1978-2007. Final Report, 18
March 2011. Oregon Cooperative Fish and Wildlife Research Unit, Department of
Fisheries and Wildlife, Oregon State University, Corvallis, Oregon, USA.

Kelly, John P., Etienne, Katherine L., & Roth, Jennifer E. (2002). Abundance and Distribution of
the Common Raven and American Crow in the San Francisco Bay Area, California. Western Birds 33(3), 202-217.

Krapu, G.L., & Reinecke, K.J. (1992). Foraging ecology and nutrition. In: Batt, B.D.J., Afton, A.D.,
Anderson, M.G., Ankney, C.D., Johnson, D.H., Kadlec, J.A., Krapu, G.L. (Eds.), Ecology and Management of Breeding Waterfowl. University of Minnesota Press, Minnesota, p1–29.

Lauten, David J., Castelein, Kathleen A., Farrar, Daniel J., Kotaich, Adam A., & Gaines, Eleanor
P. (2010). The Distribution and Reproductive Success of the Western Snowy Plover along the Oregon Coast – 2010. The Oregon Biodiversity Information Center, Portland State University/INR, Portland, Oregon, USA.

Lynch, D., Roberts, L., Falxa, G., Bown, R., Tuerler, B., & D’Elia, J. (2009). Marbled Murrelet
(Brachyramphus marmoratus): 5-Year Review. U.S. Fish and Wildlife Service, Washington Fish and Wildlife Office. Retrieved from http://www.fws.gov.

Pacific Flyway Council. (2002). Pacific Flyway management plan for Pacific brant. Pacific Flyway
Study Comm. [c/o USFWS, DMBM] Portland, OR. Unpublished report. Retrieved from http://pacificflyway.gov

Peery, Zachariah M., & Henry, William R. (2010). Recovering marbled murrelets via corvid management: a population viability analysis approach. Biological Conservation. 143,
2414-2424.

Peters, Kimberly A., & Otis, David L. (2007). Shorebird roost-site selection at two temporal
scales: is human disturbance a factor? Journal of Applied Ecology 44, 196-209

Poling, Trisha D., & Hayslette, Steven E. (2006). Dietary Overlap and Foraging Competition
Between Mourning Doves and Euarasian Collared-Doves. The Journal of Wildlife Management 70(4), 998-1004.

Rodenkirk, Timothy J., (2012). Birds of Coos County, Oregon: Status and Distribution.
Unpublished manuscript.

Scott, Virgil E., Evans, Keith E., Patton, David R., & Stone, Charles P. (1977). Cavity-nesting birds
of North American forests. U.S. Department Agriculture, Agricultural Handbook. 511, p112. Retrieved from http://www.na.fs.fed.us.

Subcommittee on Pacific Population of Western Canada Geese. (2000). Pacific
Flyway Management Plan for the Pacific Population of Western Canada Geese.
Pacific Flyway Study Committee. (c/o USFWR, MBMO) Portland, Oregon.
Unpublished report.

Terry, Lynn. (2010, January 28). Brown pelicans lingering on Oregon coast. The Oregonian.
Retrieved from http://www.oregonlive.com

Western Purple Martin Working Group. (2010). Interim population objective for the
Pacific population of the Western Purple Martin (Progne subis arboricola).
Retrieved from http://www.prbo.org

Appendix A
Glasgow Breeding Bird Survey (BBS): Oregon route #117

Species List

1986

1987

1988

1989

1990

1994

1995

1996

2005

2008

2009

2010

2011

Canada Goose

0

0

0

0

0

4

0

7

0

40

15

16

46

Wood Duck

0

0

0

0

0

0

0

2

0

0

0

0

0

Mallard

2

0

2

8

1

11

5

5

6

1

13

4

1

Northern Pintail

0

0

0

0

0

1

0

0

0

0

0

0

0

Hooded Merganser

0

0

0

0

0

0

0

0

2

0

0

0

0

California Quail

0

0

1

0

0

0

0

0

0

1

0

0

0

Ring-necked Pheasant

0

0

0

0

0

0

0

0

0

1

0

0

0

Double-crested Cormorant

0

0

0

1

3

0

1

0

54

11

5

38

6

Great Blue Heron

9

8

3

5

17

3

10

2

3

2

3

1

2

Great Egret

0

0

0

0

1

0

0

1

2

26

46

50

72

Green Heron

1

0

0

1

3

0

3

0

2

0

0

0

0

Turkey Vulture

4

8

1

5

3

8

1

15

2

14

14

7

20

Osprey

0

0

0

1

2

0

4

1

3

1

5

0

1

Bald Eagle

0

0

0

0

0

0

0

0

0

1

1

1

2

Cooper’s Hawk

0

0

0

0

0

0

0

0

0

0

1

0

0

Red-shouldered Hawk

0

0

0

0

0

0

0

0

0

0

1

0

0

Red-tailed Hawk

0

0

0

1

0

0

0

0

1

0

0

0

1

American Coot

0

0

0

0

0

0

0

0

0

2

0

0

0

Killdeer

1

2

0

2

1

0

1

0

0

0

0

0

0

Spotted Sandpiper

0

0

0

0

0

1

2

2

0

0

0

0

0

Ring-billed Gull

0

0

0

0

0

1

0

0

0

0

0

0

0

Western Gull

1

0

0

7

3

1

0

0

0

0

3

6

1

Glaucous-winged Gull

0

1

0

1

2

0

2

0

0

0

0

0

7

unid. Gull

0

0

0

0

0

0

0

0

0

0

0

0

5

Caspian Tern

0

0

0

3

0

6

0

0

0

0

0

0

0

Rock Pigeon

0

0

0

0

0

0

0

0

3

0

9

20

0

Band-tailed Pigeon

6

3

4

2

4

8

4

7

11

52

7

8

18

Eurasian Collared-Dove

0

0

0

0

0

0

0

0

0

0

0

0

5

Mourning Dove

0

0

0

0

0

0

0

2

3

2

5

0

7

Northern Pygmy-Owl

0

0

1

0

0

0

0

0

0

0

0

0

0

Common Nighthawk

0

0

0

0

0

0

1

0

0

0

0

0

2

Vaux’s Swift

0

2

0

0

0

0

0

0

0

0

3

0

13

Anna’s Hummingbird

0

0

0

0

0

0

0

0

1

0

2

1

1

Rufous Hummingbird

0

4

5

5

0

10

11

12

7

4

16

5

10

Belted Kingfisher

0

1

2

5

6

7

7

4

7

0

1

3

3

Downy Woodpecker

0

0

5

1

2

0

1

1

1

3

3

1

0

Hairy Woodpecker

1

0

0

1

0

0

1

2

0

0

0

0

1

Northern Flicker

0

0

0

0

0

0

1

0

6

2

4

3

3

Pileated Woodpecker

1

0

1

1

0

0

0

0

0

2

1

2

2

Olive-sided Flycatcher

2

3

2

0

0

1

1

1

0

0

1

2

0

Western Wood-Pewee

14

7

2

5

3

6

2

2

5

8

7

9

6

Willow Flycatcher

0

0

0

0

1

1

2

0

2

3

0

1

3

Pacific-slope Flycatcher

3

4

22

19

21

48

38

31

28

18

26

25

16

Black Phoebe

0

0

0

0

0

0

0

0

2

1

0

2

0

Cassin’s Vireo

0

0

2

0

1

1

1

4

0

0

0

0

0

Hutton’s Vireo

0

0

1

1

1

2

4

6

0

2

5

2

2

Warbling Vireo

7

6

3

12

8

29

17

18

1

4

9

5

6

Steller’s Jay

14

5

5

13

5

14

9

13

18

25

22

24

31

American Crow

26

29

12

39

25

36

51

48

52

46

55

77

68

Common Raven

1

6

2

2

4

9

8

8

1

0

2

6

7

Purple Martin

0

2

0

0

0

0

4

3

0

0

0

0

0

Tree Swallow

0

0

14

16

11

14

11

14

8

21

3

9

11

Violet-green Swallow

20

31

17

18

17

33

27

40

43

22

48

22

36

Northern Rough-winged Swallow

0

0

1

5

0

5

5

5

3

0

0

0

5

Cliff Swallow

0

1

15

18

9

1

4

11

0

0

0

0

0

Barn Swallow

20

42

24

78

32

36

43

38

23

22

16

24

61

Black-capped Chickadee

2

4

7

0

25

3

5

13

13

6

9

3

6

Chestnut-backed Chickadee

1

1

5

5

1

27

21

10

4

18

17

28

12

Bushtit

0

0

6

0

0

0

0

0

0

4

0

4

0

Red-breasted Nuthatch

1

0

1

0

1

5

4

6

4

4

3

1

5

Brown Creeper

0

0

0

0

0

0

3

0

0

0

0

0

0

Bewick’s Wren

0

0

0

0

0

2

0

0

0

0

2

1

0

Pacific Wren

2

3

8

5

6

8

16

9

2

2

1

1

12

Marsh Wren

3

0

2

0

0

4

2

6

2

8

5

8

6

Golden-crowned Kinglet

0

0

17

12

0

14

15

16

10

0

15

7

12

Wrentit

2

5

6

3

8

5

9

5

13

13

11

9

9

Swainson’s Thrush

38

31

76

73

51

78

95

43

33

39

57

26

36

American Robin

33

32

64

71

42

81

69

76

39

50

31

37

41

European Starling

6

3

14

23

12

18

19

23

41

41

13

9

37

Cedar Waxwing

2

2

8

6

0

8

9

4

13

12

16

27

6

Orange-crowned Warbler

11

13

7

8

7

10

9

6

8

2

7

5

10

MacGillivray’s Warbler

0

1

0

0

0

0

0

0

0

0

0

0

0

Common Yellowthroat

1

0

3

3

3

9

1

6

9

9

6

9

9

Yellow Warbler

0

1

0

0

0

0

0

0

0

0

1

0

2

Yellow-rumped Warbler

0

0

1

5

2

0

1

3

0

3

1

0

0

Black-throated Gray Warbler

2

2

2

3

5

1

13

13

3

2

5

6

3

Hermit Warbler

1

1

0

0

0

24

3

4

0

3

1

3

1

Wilson’s Warbler

13

16

12

12

20

37

37

29

20

14

18

22

21

Yellow-breasted Chat

0

0

0

0

0

0

0

0

0

1

0

0

1

Spotted Towhee

11

5

13

10

2

9

20

10

13

10

11

10

11

Savannah Sparrow

0

0

1

2

2

8

12

5

0

0

0

0

0

Song Sparrow

41

32

34

44

51

60

68

71

40

45

45

52

57

White-crowned Sparrow

18

15

7

9

3

17

19

18

20

19

8

15

13

Dark-eyed Junco

0

0

0

3

4

2

0

1

0

0

0

3

1

Western Tanager

9

8

4

3

1

4

7

4

1

1

0

10

7

Black-headed Grosbeak

7

15

5

4

0

9

8

14

28

11

14

22

13

Lazuli Bunting

0

0

0

0

0

1

0

0

1

0

0

0

0

Red-winged Blackbird

0

4

0

1

0

11

3

7

3

2

7

1

1

Western Meadowlark

0

0

0

2

0

0

0

0

0

0

0

0

0

Brewer’s Blackbird

0

1

2

5

0

0

0

3

5

3

5

0

3

Brown-headed Cowbird

8

9

13

12

2

15

10

8

12

5

5

7

8

Purple Finch

8

6

1

0

5

25

14

15

11

6

7

7

6

House Finch

2

3

13

11

9

4

6

12

1

7

2

6

8

Red Crossbill

0

5

0

0

0

0

0

0

2

0

0

0

1

American Goldfinch

11

11

8

19

12

17

11

21

12

22

34

17

19

Evening Grosbeak

0

0

0

0

0

1

0

1

0

0

0

0

0

House Sparrow

4

3

1

1

1

5

3

6

7

9

15

4

14

Total Species

44

46

53

56

50

60

62

62

59

58

62

59

67

Total individuals

371

397

488

631

461

820

794

778

674

708

724

734

872