Seabird Publications

Ainley, D.G., and T. James Lewis. 1974.  The history of Farallon Island marine bird populations, 1864-1972. The Condor 76: 432-446.
Abstract
The marine bird populations of the Farallon Islands, California, have long been of great interest to ornithologists. In fact, the first scientific information on the status of these populations dates back to a series of publications that, in the l850’s, marked the very beginnings of modern ornithology in western North America: the Reports, of Explorations and Surveys, to ascertain the Most Practicable and Economic Route for a Railroad from the Mississippi River to the Pacific Ocean.

Carter, H.R., V.A. Lee, G.W. Page, M.W. Parker, R.G. Ford, G. Swartzman, S.W. Kress, B.R. Siskin, S.W. Singer, and D.M. Fry. 2003. The 1986 Apex Houston oil spill in central California: seabird injury assessments and litigation process. Marine Ornithology 31:9-19. 
Abstract
Over a decade of biological and legal efforts to address impacts to seabirds from the 1986 Apex Houston oil spill in central California are summarized. This relatively small spill (616+ barrels) was conservatively estimated to have killed about 9,900 seabirds, including 6,300 Common Murres Uria aalge, as modified from earlier sources. Direct mortality was modeled using data from beached bird surveys, rehabilitation centers, at-sea surveys, and oil trajectories. Long-term impacts to depleted local populations of Common Murres and Marbled Murrelets Brachyramphus marmoratus were documented and restoration plans were developed. This incident demonstrated that small oil spills can have serious impacts to seabirds and that the amount of injury and costs of restoration must be measured before judging appropriate damages through litigation. A $6,400,000 settlement was reached in 1994 after lengthy litigation, with most funds assigned to two restoration projects in central California: a) re-establishment of breeding Common Murres at the extirpated Devil’s Slide Rock colony; and b) purchase of privately-owned, old-growth forest nesting habitat for Marbled Murrelets in the Gazos Creek watershed.

Carter, H.R., D.S. Gilmer, J.E. Takekawa, R.W. Lowe and U.W. Wilson. 2001. Breeding Seabirds in California, Oregon, and Washington.

Carter, H.R., P.J. Capitolo, W.R. McIver & G.J. McChesney.  1998. Seabird population data and human disturbance of seabird colonies in South-Central California, 1979-1995. Unpublished report, U.S. Geological Survey, Biological Resources Division, Western Ecological Research Center, Dixon, California; and Humboldt State University, Department of Wildlife, Arcata, California.

Ford, R.G., D.G. Ainley, J.L. Casey, C.A. Keiper, L.B. Spear, L.T. Ballance. 2004. The biogeographic patterns of seabirds in the central portion of the California Current. Marine Ornithology 32: 77-96.
Abstract
We assessed seabird distributions in the central California Current system by compiling and integrating data from all major seabird distributional studies conducted in the region since 1980. Studies in the compilation included the Minerals Management Service Aerial
Surveys, the Seabird Ecology Study,the National Marine Fisheries Service (NMFS) Rockfish Assessment cruises,the National Oceanic and Atmospheric Administration Eastern Pacific Ocean Climate Study cruises, the California Department of Fish and Game Office of Spill Prevention and Response overflights, the San Francisco Deep Ocean Disposal Site cruises and the NMFS Oregon, California and Washington Marine Mammal Survey cruises. Those surveys were used to examine, by oceanographic season, the spatial and temporal distribution of the five most abundant seabird species, and the community biomass and species diversity for the entire seabird community. Noteworthy was the high species diversity along the shelf break (200-m isobath) and a marked high-density “halo” of individuals of breeding species around major nesting colonies during the breeding season.

Manuwal, D. A., H. R. Carter, T. S. Zimmerman, and D. L. Orthmeyer, Editors. 2001. Biology and conservation of the common murre in California, Oregon, Washington, and British Columbia. Volume 1: Natural history and population trends. U.S. Geological Survey, Biological Resources Division, Information and Technology Report USGS/BRD/ITR-2000-0012, Washington, D.C. 132 pp.

Stenzel, L.E., H.R. Carter, R.P. Henderson, S.D. Emslie, M.J. Rauzon, G.W. Page, P.Y. O’Brien. 1995. 1995. Breeding success of Double-Crested Cormorants in the San Francisco bay area, California. Colonial Waterbirds 18: 216-224.
Abstract
Colony size and nesting success of the Double-crested Cormorant (Phalacrocorax auritus) was examined during 1988-90 on the Richmond-San Rafael Bridge (= Bridge) in the San Francisco Bay estuary and at a reference colony on the Farallon Islands, for evidence that pollutants could be harming cormorant reproduction in the estuary. The Bridge colony increased by 43% from 296 to 424 nests by 1990, while the Farallon Island colony (= Island) remained relatively stable at about 290 nests over the three years. Nesting was earlier on the Island than on the Bridge in all years, but on the Bridge there was a trend toward earlier nesting from 1988 to 1990. Success was higher on the Island in 1988, but on the Bridge in 1989 and 1990. The overall mean number of chicks (±SE) fledged per nest was: 0.98±0.07, 1.78±0.06 and 1.70±0.06 on the Bridge versus 1.29±0.07, 1.13±0.05 and 0.61±0.05 on the Island from 1988-90, respectively. During 9 of 11 time-periods examined, Bridge nesters had higher success than did Island nesters. Poor success on the Bridge in 1988 matched a later timing of nest initiations. Breeding success decreased seasonally at both locations. Breeding success at both colonies was comparable to that reported for other colonies. There was no evidence that reproductive success or colony size was depressed by pollutants at the San Francisco Bay colony.

Takekawa, J.E., H.R. Carter, and T.E. Harvey. 1990. Decline of the common murre in central California, 1980-1986. Studies in Avian Biology. 14: 149-163.
Abstract
Aerial surveys of 13 Common Murre (Uria aalge) colonies were conducted in California in 1985 and 1986. Breeding population estimates for eight colonies in central California and five colonies in northern California were compared with estimates determine din 1980-1982. The central California population declined 52.6% within 4-6 years, from 229,080 in 1980-1982 to 108, 530 in 1986. The northern California population remained relatively unchanged during the same period; combined totals at four colonies declined 5.4% from 118,080 in 1979-1982 to 111,730 in 1986. Population decline in central California was caused by high mortality from an intensive nearshore gill-net fishery, compounded by that from oil spills and a severe El Nino-Southern Oscillation event in 1982-1983. Individuals colonies declined 45.8-100% and the most severe declines occurred at colonies located nearest to areas of highest gill-net fishing mortality.

Anderson, J.G.T. and C.M. Devlin. 1999. Restoration of a multi-species seabird colony. Biological Conservation 90: 175-181.
Abstract
Nesting herring and great black-backed gulls (Larus argentatus and Larus marinus) were removed from a recently abandoned tern (Sterna sp.) colony through a combination of poisoning and shooting. Following gull control, all three species of tern that had nested in the colony prior to the arrival of the gulls returned and nested in increasing numbers. In addition to the restoration of the terns, removal of the gulls led to colonization and/or significant increases in populations of four other seabirds. Gull numbers were greatly reduced by initial poisoning efforts, but continued immigration from surrounding colonies has required an on-going program of shooting to eliminate territorial birds nesting in areas utilized by terns and other species. In situations calling for active management we advocate rapid, focused intervention, and stress the importance of inter-organizational cooperation, and an active program of public education.

Anderson, D.W. 1988. Dose-Response Relationship between Human Disturbance and Brown Pelican Breeding Success. Wildlife Society Bulletin 16: 339-345.
Abstract
The brown pelican nesting colony at Isia Coronado Norte was monitored from 1969 to
1987. Most of the activity on the island is related to a fishing camp. There was essentially only one type of human disturbance, humans walking along trails to visit cache sites at various locations. The disturbances were only related to trails, and occurred once every 1-2 weeks throughout the nesting season each year. Anderson found that the colony has been disturbed to such an extent that nesting success has been reduced and nesting populations on that island are threatened. Nest abandonment’s increased with nearness to human activity, and human disturbance versus nesting success followed a typical dose-response pattern. Pelicans were affected at distances less than about 600m, illustrating the sensitivity of brown pelicans to human disturbance.

Anderson, D.W. and J.O. Keith. 1980. The human influence on seabird nesting success: conservation implications. Biological Conservation 18: 65-80.
Abstract
Based on studies of brown pelicans Pelecanus occidentalis californicus and Heermann's gulls Larus heermanni, disturbances by recreationists, educational groups, local fishermen and scientists alike can be seriously disruptive and damaging to breeding seabirds in the Gulf of California and off the west coast of Baja California. Similar instances have been identified throughout the world—the problem is not difficult to document, but it is difficult to eliminate. The increasing human-seabird contacts on islands in the Gulf of California and along the west coast of Baja California raise serious questions and immediate concern about the continued preservation of nesting colonies of marine birds in those areas. Conservation measures must consider the extreme sensitivity of many seabirds to the inter- and intraspecific behavioural imbalances created by human disturbances. In some cases, total exclusion of humans may be required; in others, limited access might be possible under closely managed conditions at certain times of the year. A symbiotic relationship between seabird conservation, legitimate research and tourism should be the desired goal.

Beale, C.M. 2007. Managing visitor access to seabird colonies: a spatial simulation and empirical observations. Ibis 149: 102-111.
Abstract
Managers of wildlife reserves have a range of tools available to them when considering the best way to provide visitor access while avoiding as many of the negative effects of human disturbance as possible. However, managers lack guidelines as to whether conservation interests are best met by spreading visitors thinly throughout a reserve or by aggregating them in a small area. Here I describe how relationships between disturbance impact and disturbance pressure (the dose–response curve) can be used to address this issue. I generate a spatial simulation of two different models of visitor distribution (one more aggregated than the other) and explicitly model disturbance impact for a variety of dose–response curves. I show that the optimal visitor distribution is likely to depend on the sensitivity of the species and the overall visitor pressure. Importantly, I find that in certain circumstances optimal management can shift from one management option to the other if visitor numbers cross a certain threshold. I use published relationships predicting nesting success of Common Guillemots Uria aalge and Black-legged Kittiwakes Rissa tridactyla to assess optimal management at three nature reserves in Scotland. Optimal management for Guillemots depends on the number of people and the distance between the people and the birds. At sites with high disturbance pressures, management should aim to aggregate visitors in as small an area as possible, whereas at sites with lower disturbance pressure, an even distribution of visitors is favoured. Kittiwake models were not generally accurate, and consequently only site-specific guidelines could be generated, where an even distribution was favoured. 

Beale, C.M. and P. Monaghan. 2005. Modeling the Effects of Limiting the Number of Visitors on Failure Rates of Seabird Nests. Conservation Biology 19: 2015-2019.
Abstract
Most attempts to manage disturbance by visitors to nature reserves concentrate on limiting visitor access in some way, which is often unpopular with both visitors and managers. In a few nature reserves the daily numbers of visitors are limited, an action that need not necessarily reduce the total number of visitors. As a test of the assumptions that underlie this management practice, we examined the relationship between daily visitor numbers and daily failure rates of nests in two species of seabirds. Daily failure rates for Black-legged Kittiwakes (Rissa tridactyla) were weakly correlated with daily visitor numbers but indicated that capping daily visitor numbers slightly reduced overall breeding success. This was not the case for Common Murres (Uria aalge), where failure rate declined seasonally but was not significantly correlated with visitor numbers. For some species, it appears that capping daily visitor numbers may have small conservation costs.

Blackmer, A.L., J.T. Ackerman and G.A. Nevitt. 2004. Effects of investigator disturbance on hatching success and nest-site fidelity in a long-lived seabird, Leach's storm-petrel.Biological Conservation 116: 141-148.
Abstract
Long-lived animals are expected to reduce reproductive effort when breeding conditions are unfavorable, therefore seabirds may be especially sensitive to investigator disturbance. In a non-threatened procellariiform, Leach's storm-petrel Oceanodroma leucorhoa, we examined whether the frequency and the time of day of investigator disturbance influenced hatching success, and if disturbance affected hatching success and nest-site fidelity in the subsequent breeding season. Birds used in this study had received little or no investigator disturbance during the prior decade. Hatching success was significantly influenced by the frequency, but not the time of day, of disturbance. Weekly and daily handling of parents reduced hatching success by 50 and 56% compared to the control group. Most failures (91%) were caused by egg desertion, and all the deserted eggs belonged to pairs in the weekly and daily groups. During the subsequent breeding season, the hatching success of disturbed pairs that continued to breed together returned to normal levels. However, 37% more disturbed pairs than control pairs deserted the nesting burrows they had used in the previous year. Since most changes in nest site also result in mate change, investigator disturbance may have had long-term negative effects on reproductive success as well. Our results demonstrate that both weekly and daily investigator disturbance during incubation greatly reduced the hatching success and subsequent nest-site fidelity of naïve Leach's storm-petrels.

Blumstein, D.T., E. Fernandez-Juricic, P.A. Zolliner and S.C. Garity. 2005. Inter-specific variation in avian responses to human disturbance. Journal of Applied Ecology 42: 943-953.
Abstract
1. Increasing urbanization and recreational activities around and within biodiversity hotspots require an understanding of how to reduce the impacts of human disturbance on more than a single species; however, we lack a general framework to study multiple species. One approach is to expand on knowledge about the theory of anti-predator behaviour to understand and predict how different species might respond to humans.
2. We reviewed the literature and found that only 21% of studies that used a behavioural approach to study human disturbance focused on multiple species. These studies identified a number of potential predictive variables.
3. We developed a simulation model that investigates interspecific variation in different parameters of disturbance with variation in human visitation. We found that fitness-related responses, such as the quantity of food consumed by a species, are relatively sensitive to the distance at which animals detect humans, the frequency of disturbance by humans and the interaction of these factors, but are less sensitive to other characteristics.
4. We examined avian alert distance (the distance animals first orientated to an approaching threat, a proxy for detection distance) across 150 species, controlling for phylogenetic effects. We found that larger species had greater alert distances than smaller species, which could increase local spatial and temporal limitations on suitable habitat with increasing human visitation.
5. Synthesis and applications. Our results suggest that body size could be a potential predictor of responses to human disturbance across species, and could be used by managers to make conservation decisions regarding levels of human visitation to a protected site. We suggest that three things are essential to develop predictive models of how different species will respond to human disturbance. First, multiple indicators of disturbance should be studied to select those with lower intraspecific variation for a given study system. Secondly, the species-specific nature of responses should be identified. Thirdly, life history, natural history and other correlates with these species-specific responses must be assessed.

Brown, A.L. 1990. Measuring the effect of aircraft noise on sea birds. Environment International 16: 587-592.
Abstract
This paper reports on a procedure which exposes sea birds to acoustic stimuli simulating aircraft overflights, and is one of the first experiments to attempt to quantify the responses of birds in the wild to noise. The experiment, conducted on Australia's Great Barrier Reef, involved presentation of pre-recorded aircraft noise, with peak overflight levels of 65 dB(A) to 95 dB(A), to nesting sea bird colonies. Sea bird responses were videotaped and these tapes were subsequently analysed by scoring the behavioural response of each bird in the colony. Results of a trial of this experimental procedure for one species, the Crested Tern (Sterna bergii), indicate that the maximum responses observed, preparing to fly or flying off, were restricted to exposures greater than 85 dB(A). A scanning behaviour involving head-turning was the minimum response, and this, or a more intense response, was observed in nearly all birds at all levels of exposure. However an intermediate response, an alert behaviour, demonstrated a strong positive relationship with increasing exposure. While the experiment has provided good control on simulated aircraft noise levels, preliminary observations of response of the colonies to balloon overflights suggests that visual stimulus is likely to be an important component of aircraft noise disturbance.

Burger, J. 1981. Behavioral Responses of Herring Gulls Larus argentatus to Aircraft Noise.Environmental Pollution 24: 177-184.
Abstract
The behavior of nesting and loafing L. argentatus was compared when the birds were exposed to supersonic transport, subsonic aircraft and normal colony noises at Jamaica Bay National Recreational Area. When supersonic transports flew over, significantly more nesting gulls flew from their nests, and they engaged in more fights when they landed compared with the other conditions. Many eggs were broken during these fights, and subsequently eggs were eaten by intruders. At the end of the incubation period there were lower mean clutch sizes in dense sections of the colony. For loafing gulls, significantly more birds flushed when planes flew over compared with immediately before and after such plane noises.

Burger, J and J. Gallie. 1987. Factors Affecting the Distribution of Gulls (Larus spp.) on Two New Jersey Coastal Bays. Environmental Conservation 14: 59-65.
Abstract
Gulls of the genus Larus are important components of coastal and marine ecosystems, and hence can constitute a factor of substantial environmental significance. Yet their relative contribution to coastal avifaunas, and the basic factors affecting their distribution along coasts, are rarely studied. Because gulls are so common along coasts, and tend to frequent areas that are used extensively by people, they are usually considered to be undisturbed by the presence of human beings. In this study the authors examine human-related and environmental factors affecting the distribution of gulls in two large bays in New Jersey, on the east coast of the United States (Delaware and Raritan Bays). In addition to the effects of human activities on gull presence, the authors were interested in the effects of temporal (season and time-of-day), spatial (location along the bays), and physical (tides, winds, and precipitation), factors.

Burger, J. and M. Gochfield. 1983. Behavioural Responses to Human Intruders of Herring Gulls (Larus argentatus) and Great Black-backed Gulls (L. marinus) with Varying Exposure to Human Disturbance. Behavioural Responses 8: 326-344.
Abstract not available

Carney, K.M. & W.J. Sydeman. 1999. A review of human disturbance effects on nesting colonial waterbirds. Waterbirds 22: 68-79.
Abstract
We reviewed 64 published investigations concerning effects of human disturbance on nesting colonial waterbirds. We summarized and reviewed articles, based on taxonomy, examining investigator, ecotourist, recreator, watercraft, and aircraft activity effects on physiology, reproductive behavior, reproductive success, and population trends of waterbirds. Though most studies found significant negative effects, taking careful measures minimized impact on some species. Guidelines for minimizing investigator and visitor disturbance are outlined. Little practical information for visitor management is available. Increasing pressure from the ecotourism industry to visit waterbird colonies makes research that develops scientifically-defensible tourism policies imperative.

Dunnet, G.M. 1977. Observations on the effects of low-flying aircraft at seabird colonies on the coast of Aberdeenshire, Scotland. Biological Conservation 12: 55-63.
Abstract
The greatly increased use of helicopters and fixed-wing aircraft to support the exploration and exploitation of oilfields in the North Sea gives rise to concern about possible disturbance to seabirds breeding in the flight paths. The observations reported in this paper were made at a mixed colony of fulmars (Fulmarus glacialis), shags (Phalacrocorax aristotelis), herring gulls (Larus argentatus), kittiwakes (Rissa tridactyla), guillemots (Uria aalge), razorbills (Alca torda), and puffins (Fratercula arctica), breeding on the Buchan cliffs about 40 km north of Aberdeen, on two days during egg-laying and early nestling stages of the breeding season. The numbers of birds in attendance at nests or nesting ledges were counted before and after the passage of aircraft, and general observations were made when the planes were overhead. The number of identifiable nests with 0, 1 or 2 adults was noted since disturbance might be most sensitively detected by the departure of non-incubating/brooding adults. No evidence was found to suggest that aircraft flying at heights of about 100 m above the cliff-top affected the attendance of incubating and brooding birds, and there was only a slight indication that a few of the ‘second adults’ at kittiwake nests may have flown off. Groups of kittiwakes resting on nearby cliffs or on the sea did take to the air in response to the planes, but they also did so frequently in the course of the day with no obvious cause. It is stressed that these findings cannot be extrapolated to other species of seabirds or to different conditions.

Erwin, R.M. 1989. Responses to Human Intruders by Birds Nesting in Colonies: Experimental Results and Management Guidelines. Colonial Waterbirds 12: 104-108.
Abstract
Colonies of nesting wading birds and seabirds were studied at coastal sites in Virginia and North Carolina to determine distances at which birds flushed in response to human intrusion. Observers measured up to 3 distances: these were (i) a "dread," or initial panic, (ii) the distance at which the first individual flushed, and (iii) the distance at which the majority of the colony flushed. The total time that birds spent in the air after flushing was also recorded. Mixed colonies of Common Terns-Black Skimmers responded at the greatest distances ("dread"), with respective means of 142 and 130 m; mixed wading bird species were more reluctant to flush (30-50 m average). There were few statistically significant relationships between flushing distances and colony size. Similarly, there were few differences between responses during incubation compared to post-hatching periods. The disturbance distances measured in this study are much greater than the 50 m guideline suggested in a 1976 National Park Service report. I recommend distances of 100 m for Least and Royal Terns and wading birds and 200 m for Common Terns and skimmers for sign-posting of established colonies. Greater distances will be necessary as a buffer before birds become established at a site.

Erwin, R.M. 1980. Breeding habitat use by colonially nesting waterbirds in two mid-Atlantic US regions under different regimes of human disturbance. Biological Conservation 18: 39-51.
Abstract
More than 80% of the beach-nesting seabirds (common tern, least tern, black skimmer, and herring gull) in coastal Virginia nest on natural barrier island beaches, while in New Jersey the vast majority nest on dredge deposition material or natural marsh islands. This contrast probably results from the differences in human disturbance in the two regions. Although 75% of all oceanfront in New Jersey allows unrestricted recreation, about 85% of the Virginia beaches are ‘protected’ under the ownership of several conservation agencies. Attendant with changes in habitat utilisation in New Jersey, competitive interactions have apparently intensified with herring gulls usurping tern and laughing gull nest sites. Other implications are discussed.

Gill, J.A. 2007. Approaches to measuring the effects of human disturbance on birds. Ibis 149: 9-14.
Abstract
Human recreational activities are often considered as potential threats to biodiversity, by restricting animals’ access to resources that otherwise would be exploited. Because access to wildlife areas is one major means of increasing their public value, and hence the pressure to conserve them, it is clearly critical to be able to identify accurately when human presence is a threat to conservation and when it is not. A wide range of methods have been used to assess the impacts of human disturbance on wildlife and these methods are summarized here. The type of method used depends principally on whether the disturbance issue relates to a particular site, a particular group of individuals or whole populations. Within these categories, both comparative and experimental approaches have been used to assess behavioural, distributional, demographic and population responses to human presence. Examples of each approach are given here, together with an assessment of the information each method provides.

Hand, J.L. 1980. Human disturbance in Western Gull Larus occidentalis livens colonies and possible amplification by intraspecific predation. Biological Conservation 18: 59-63.
Abstract
Indirect evidence is presented that human disturbances are having a profound effect on reproductive efforts of Larus occidentalis livens at several colonies in the Gulf of California. Breeding adults that lose their eggs or chicks apparently practise conspecific predation whether or not humans are present, thus increasing effects of human intrusions. These combined effects could lead to a severe decline in numbers or even pose a threat to the survival of this endemic population, if human disturbance is widespread. Attempts to assess breeding success throughout the Gulf seem warranted and, if necessary, some action to regulate human contact may be essential.

Haynes, A.M. 1987. Human exploitation of seabirds in Jamaica. Biological Conservation 41: 99-124.
Abstract
All nesting species of seabirds in Jamaica are exploited or seriously disturbed by people. The species which are most affected are sooty terns Sterna fuscata and brown noddies Anous stolidus. Collection of eggs for the local luxury market is the most detrimental form of exploitation. The evidence of a decline in the Jamaican populations and the possible causes of this decline are reviewed. Past and present management strategies are critically evaluated and recommendations made for future policy and research.

Holmes, N.D., M.G., H. Achurch, S. Robinson, L.K. Kriwoken. 2006. Behaviour and breeding success of gentoo penguins Pygoscelis papua in areas of low and high human activity. Polar Biology 29: 399.
Abstract
Port Lockroy, situated on the Antarctic Peninsula, is one of the most visited tourist sites in Antarctica. The effects of visitor disturbance on the breeding performance of gentoo penguins (Pygoscelis papua) at Goudier Island, Port Lockroy was investigated during the austral summer of 1996/1997 by comparing pairs in treatment areas (visited by 35-55 tourists every 1-2 days) and control colonies (not visited by tourists). There were no differences between the two groups in the proportion of birds that laid, in hatching success or the proportion of single-chick broods. Pairs in treatment colonies laid a higher proportion of single-egg clutches, but this was related to colony location and unusually high snow accumulation. Most treatment colonies were situated on low-lying ground or in the lee of buildings, and probably had more late layers at the initial census. Only 11% of tourist visits had occurred by laying, making human disturbance an unlikely explanation for the higher proportion of single-egg clutches. Nests monitored in a disturbed colony and a control colony showed no differences in chick mass or survival up to 20 days of age. The overall breeding success, based on counts of creched birds, was similar to other southern populations of gentoo penguins, after correcting for mortality between creching and fledging. Historical data from Goudier Island indicate that the colony established itself in 1985 and has rapidly increased in size since then. The neighbouring colony at Alice Creek, which has been regularly visited by tourists for at least a decade, has also shown a population increase, although this expansion has been at a slower rate. We conclude that disturbance from tourist visits is unlikely to have been a major determinant of gentoo population change at Port Lockroy.

Klein, M.L., S.R. Humphrey, and H.F. Percival. 1995. Effects of Ecotourism on Distribution of Waterbirds in a Wildlife Refuge. Conservation Biology 9: 1454-1465.
Abstract
Humans visiting natural areas often disturb wildlife, possibly displacing animals from desirable habitat. To hold ecotourism at acceptable levels refuge managers need to know which species are likely to be affected and which response occurs at different levels of disturbance. Displacement of waterbirds at J. N. "Ding" Darling National Wildlife Refuge, Florida (U.S.A.), by specific human activities was demonstrated experimentally by Klein in 1993. We assessed the extent of this effect of ecotourism on the distribution of 38 species of waterbirds by surveying birds in plots of known distance from a dike along which wildlife tours occurred. Most resident species were less sensitive to disturbance than were migrants. Migrant ducks were most sensitive when they first arrived, mid-October to mid-December, usually remaining more than 80 m from the drive, even at low levels of human visitation. Herons, egrets. Brown Pelicans (Pelecanus occidentalis), and Anhingas (Anhinga anhinga) were most likely to remain close to areas of high human activity. Shorebirds were displaced at intermediate distance and visitation levels. Mottled Ducks (Anas fulvigula) and several of the ardeids seemed to include two groups differing in behavior, one habituated to humans and one sensitive to disturbance. Public education and changes in management practices are needed to reduce disturbance. Guided tours and low-disturbance zones where people stay in their cars could reduce the negative effects of tourists, especially in the fall when migrants arrive. The number of human visitors may have to be reduced or the wildlife drive closed on certain days during the tourist season.

McChesney, G. J., L. E. Eigner, T. B. Poitras, P. J. Kappes, D. Le Fer, L. T. Nason, P. J. Capitolo, H. Beeler, C. E. Fitzpatrick, R. T. Golightly, K. S. Bixler, H. R. Carter, S. W. Kress, and M. W. Parker. 2006. Restoration of Common Murre colonies in central California: annual report 2005. Unpublished report, U.S. Fish and Wildlife Service, San Francisco Bay National Wildlife Refuge Complex, Newark, California (prepared for the Apex Houston and Command Trustee Councils).

McChesney, G. J., N. M. Jones, T. B. Poitras, K. J. Vickers, L. E. Eigner, H. R. Carter, R. T. Golightly, S. W. Kress, M. W. Parker, K. Studnicki, P. J. Capitolo, and J. N. Hall. 2005. Restoration of Common Murre colonies in central California: annual report 2004. Unpublished report, U.S. Fish and Wildlife Service, San Francisco Bay National Wildlife Refuge Complex, Newark, California (prepared for the Apex Houston Trustee Council).

Mills, Kyra L, W.J. Sydeman, and P.J. Hodum (Eds.). 2005. The California Current Marine Bird Conservation Plan, v. 1, PRBO Conservation Science, Stinson Beach, CA.

Muñoz del Viejo, A., X. Vega, M.A. González, and J.M. Sánchez. 2004. Disturbance sources, human predation and reproductive success of seabirds in tropical coastal ecosystems of Sinaloa State, Mexico. Bird Conservation International14: 191-202.
Abstract
From March to July 2000, four seabird colonies in coastal ecosystems of Sinaloa, north-west Mexico were visited: on islets, a sandy beach and a long-abandoned salt-panning flat. There were partial and total breeding failures, most of them due to human activity. Amongst colonies of nine species, the breeding success of three was severely affected. All 250 Royal Tern Sterna maxima eggs were taken for direct consumption; 50% (75) of Blue-footed Booby Sula nebouxii chicks were killed for crab (Portunidae) fishing; and in a Least Tern Sterna antillarum colony (97 pairs), 50% failed due to disturbance from a fishing championship. Some of these species have priority status within Mexican and international conservation regulations. Certain aspects of these problems are discussed, and actions are suggested to balance conservation and the development of economic activities.

Murphy, M.A., N.M. Jones, and M.W. Parker. 2005. Common Murre Egg Recovery. Waterbirds 28: 402-403.
Abstract
Common Murre (Uria aalge) breeding success has been monitored in 1996-2004 at Devil’s Slide Rock, California as part of a restoration project related to the Apex Houston oil spill. During the 2001 breeding season, two separate cases of egg recovery by parent murres were observed. During the first event an egg was secured and incubated 60 cm from the original nesting site, while in the second case an egg was retrieved after rolling 85 cm. The first egg was lost within 24 hours, and the second disappeared within a day of its expected hatching date. We describe the circumstances surrounding these events, including the behavior of the parent murres during the egg recovery attempts, the subsequent fate of the recovered eggs, the microhabitat features associated with egg loss and other factors affecting the egg recovery ability of adult murres.

Parrish, J.K., P. Ayers, K. Litle, and J. Dolliver. 2005. Overflight Monitoring in the West Coast National Marine Sanctuaries. Unpublished report, University ofWashington, School of Aquatic and Fishery Sciences, Seattle, Washington.

Pierce, DJ; Simons, TR. 1986. The influence of human disturbance on tufted puffin breeding success. Auk 103: 214-216.
Abstract
Short communications: Burrow-nesting alcids are vulnerable to human disturbance, but little quantitative information exists on the impact of researcher disturbance on estimates of alcid breeding success. The authors estimated their influence on tufted puffin (Fratercula cirrhata) reproductive success as part of a larger study of seabird ecology on the Barren Islands, Alaska.

Robert, H.C., C.J. Ralph. 1975. Effects of Human Disturbance on the Breeding Success of Gulls. The Condor 77: 495-499.
Abstract
Short Communications: A number of factors have been suggested as affecting reproductive success in gulls. In this study we have attempted to isolate the effect of human disturbance on breeding success. We held other factors such as age of birds, terrain, and density of colony as constant as was practicable with a varied colony environment. There have been several previous discussions of the possible effect of human disturbance on the breeding success of birds. However, no study has documented this effect with controls.

Rojek, N.A., M. W. Parker, H.R. Carter, and G. J. McChesney In prep. Aircraft and vessel disturbance of Common Murres in central California, 1997-1999.
Abstract
From 1997 to 1999, we documented aircraft disturbances of Common Murres (Uria aalge) at three central California breeding colonies (Castle-Hurricane Colony Complex; Devil’s Slide; and Point Reyes). Most disturbances occurred when flyovers were <305 m ASL. Helicopters tended to cause more disturbance than fixed-wing aircraft, likely due to higher noise levels. At Castle-Hurricane, low aircraft flyovers occurred 49% and 656% more frequently than at Devil’s Slide Rock and Point Reyes, respectively. Flyovers also resulted in flushing of adult murres more frequently at Castle-Hurricane (31% of flyovers) and Point Reyes (25%) compared with Devils’s Slide, (4%). Boat disturbance to murres also was substantially higher at Castle-Hurricane than the other two colonies, resulting in lost eggs and chicks. Most boat disturbance occurred when vessels approached within 50 m of active nesting areas and remained in the area for extended periods. The Castle-Hurricane Colony Complex declined extensively during the early 1980s due mainly to mortality from gill net fishing and oil spills. While numbers increased at most colonies in the 1990s, the Castle-Hurricane Colony Complex only partly recovered to about half of pre-decline numbers by 1997. While population impacts are difficult to measure, disturbance effects probably are additive to impacts from continued mortality from gill-net mortality and other factors that have led to slow recovery at this colony complex.

Ronconi, R.A. and C.C. St. Clair. 2002. Management options to reduce boat disturbance on foraging black guillemots (Cepphus grylle) in the Bay of Fundy. Biological Conservation 108: 265-271.
Abstract
Boat disturbance of foraging black guillemots (Cepphus grylle) was studied at a breeding colony in the Bay of Fundy, Canada. Using observations from a cliff top, flushing behaviour was examined in relation to boat characteristics, guillemot behaviour, and environment conditions. The distance guillemots foraged from shore and the size, speed, and approach distance of boats were important factors predicting flushing probability. Guillemots foraged further from shore at low tide presumably making them more vulnerable to disturbance then. Using these results to identify the conditions that would minimize disturbance, management recommendations on boat speed and set-back distance were developed. At this site, a set-back distance of 600 m from shore with a speed limit of 25 km/h would reduce guillemot flushing probability to 10% most of the time. Although specific management options are proposed for this particular colony, the analytical approach used to identify an appropriate set back distance and some of the specific results are relevant to other locations and colonial waterbird species.

Saenz, B.L., J.A. Thayer, W.J. Sydeman, D.A. Hatch. 2006. An urban success story: breeding seabirds on Alcatraz Island, California, 1990-2002. Marine Ornithology 34: 43-49.
Abstract
Located in the San Francisco Bay estuary, Alcatraz Island has in recent years become an important breeding site for seabirds, including Brandt’s Cormorant Phalacrocorax penicillatus, Pelagic Cormorant P. pelagicus, Pigeon Guillemot Cepphus columba and Western Gull Larus occidentalis. We synthesized available data on breeding populations from 1990–2002 for those four species and calculated annual productivity in 1997–2002 for Brandt’s Cormorants and 1999–2002 for Pelagic Cormorants and Western Gulls. Population trends and productivity were compared to those on larger, offshore Southeast Farallon Island (SEFI). Brandt’s Cormorants established a colony that grew to more than 460 breeding pairs during the study period. Small populations of Pelagic Cormorants and Pigeon Guillemots on Alcatraz remained relatively stable during 1995–2002. Breeding Western Gulls increased at a 6.0% annual rate from 1990–2002. Productivity of
Brandt’s Cormorants and Western Gulls on Alcatraz was higher than on SEFI in the years monitored. We propose that high availability of forage fishes in the San Francisco Bay estuary, combined with seasonal protection of nesting habitat, contributed to the recent growth and success of Alcatraz seabird populations. Because seabirds on Alcatraz breed in close proximity to myriad human activities, they present a unique opportunity to investigate the ecology of urban seabird populations.

Taylor, Graeme A. Action plan for seabird conservation in New Zealand. Part A, Threatened seabirds / by Graeme A. Taylor. Wellington, N.Z. : Dept. of Conservation, Biodiversity Recovery Unit, 2000.

Thayer, J.A., W.J. Sydeman, N.P. Fairman & S.G. Allen. 1999. Attendance and effects of disturbance on coastal common murre colonies on Point Reyes, California. Waterbirds 22: 130-139.
Abstract
We surveyed six Common Murre (Uria aalge) colonies in the vicinity of Elephant Seal Cove Beach (ESCB), Point Reyes National Seashore, Marin County, California from 1995 through 1997 to investigate the effects of disturbance on local murre populations in the wake of a small shipwreck and to establish seasonal and diurnal attendance patterns of coastal murre populations. Following the shipwreck in 1995, one colony (Cliff Rock West) was abandoned, and three others (Flattop Rock, Mid Rock, and East Rock) experienced reduced productivity due to disturbance and predation by Brown Pelicans (Pelecanus occidentalis), Western Gulls (Larus occidentalis), and Common Ravens (Corvus corax). A fifth colony, Face Rock, farthest from the grounding site, was apparently not affected. Murres attended Cliff Rock West only early in 1996, and not at all in 1997. A new colony formed on another seastack (Northwest Rock) after murres left the Cliff Rock West colony in 1996. However, no eggs were observed at Northwest Rock in 1996 and this colony was abandoned early in 1997. Seasonal attendance among colonies on Flattop Rock, Mid Rock, and East Rock followed a similar trend in both 1996 and 1997. Murre attendance fluctuated widely until the onset of egg-laying in early May, but then stabilized and increased somewhat until July, when numbers began to drop at the end of the fledging period. Both air temperature and the upwelling index (UI) were significantly correlated with murre attendance in May and June during the incubation and nestling periods. Mean attendance increased 18-30% at these colonies between 1996 and 1997. Diurnal attendance in 1996 and 1997 varied both within and between colonies and days, yet there was a significant downward trend in numbers throughout the day, as well as an effect of colony disruption by other marine species. Given that seasonal and diurnal attendance patterns of Flattop, East, and Mid Rocks in 1996 and 1997 appear similar, both between years and to other studies, we assume that these colonies recovered quickly following the 1995 shipwreck. However, interspecific interactions and predation continue to affect diurnal attendance patterns and productivity of these colonies.

U.S. Fish and Wildlife Service. 2005. Regional Seabird Conservation Plan, Pacific Region. U.S. Fish and Wildlife Service, Migratory Birds and Habitat Programs, Pacific Region, Portland, Oregon.

Yasué, M., P. Dearden. 2006. The potential impact of tourism development on habitat availability and productivity of Malaysian plovers Charadrius peronii. Journal of Applied Ecology 43: 978-989.
Summary
1. Increased human pressure on coastal habitats has contributed to the global population decline in waders. Although coastal development can be particularly rapid and poorly regulated in tropical countries, very little research has been conducted to assess the extent of these impacts in the tropics.
2. We examined the potential effects of human disturbance and tourism-related habitat changes on Malaysian plovers breeding on sandy tropical beaches.
3. In 2004 and 2005, we monitored 54 and 79 pairs of Malaysian plovers in the Gulf of Thailand, and used logistic habitat models to identify factors influencing habitat selection and breeding success. These models included variables affected by anthropogenic changes such as human disturbance and vegetation structure, as well as other natural factors such as prey availability and predator densities. We also assessed causes of nest failure and conducted 372 h of behavioural observations to identify mechanisms that relate important habitat variables to plover productivity.
4. Plovers selected wide beaches with low levels of human disturbance that had a low percentage cover of tall trees backing the beach. The likelihood of hatching clutches and fledging chicks was greater in territories with low levels of human disturbance, low conspecific density and high percentage cover of 0·5–5 m tall vegetation backing the beach.
5. Nest monitoring and behavioural observations suggested that heightened vulnerability to tidal inundation, trampling, heat stress, predators and territorial conflicts may have contributed to the results from the habitat models.
6. We conclude that tourism development on Thai beaches affects both habitat availability and productivity of Malaysian plovers by enhancing beach erosion rates, converting medium vegetation into tall monocultures and intensifying human disturbance. These direct effects of habitat loss may be exacerbated by density-dependent reductions in productivity.
7. Synthesis and application. This study demonstrates the value of combining three approaches: habitat modelling, nest monitoring and behavioural observations, for identifying impacts of anthropogenic changes on breeding birds and assigning ultimate causes. In understudied regions where there are pressing threats to wildlife, this approach may focus research efforts so that the necessary data can be obtained rapidly in order to assess and predict human impacts.

Yorio, P., E. Frere, P. Gandini, and A. Schiavini. 2001. Tourism and recreation at seabird breeding sites in Patagonia, Argentina: current concerns and future prospects. Bird Conservation International 11: 231-245.
Abstract
Seabird colonies often constitute valuable tourist attractions. Different species differ in their sensitivity to human disturbance and, although birds may habituate to visitors, inappropriate intrusions at poorly managed sites may result in adverse effects on breeding individuals. The rapid growth of wildlife-based tourism and recreation in coastal Patagonia, Argentina, presents opportunities for significant economic benefits but also raises concerns about the potential effects on seabird colonies. Sixteen seabird species breed along the Patagonian coast, with Magellanic Penguin Spheniscus magellanicus being one of the main tourist attractions. At least 27 sites where seabirds breed are currently visited by people either through organized tourism or for recreational purposes, 19 of which are included in coastal protected areas. The number of visitors per year varies from 50 to more than 100,000, depending on the site. Negative effects on seabird reproduction in Patagonia are through direct destruction of nests or their contents and desertion of offspring, particularly at locations where seabirds nest in association with or near to colonies of avian predators. Tourism and recreation activities are growing in extent and intensity at most coastal sectors in Patagonia. Current trends in coastal recreation activities may result in negative effects on breeding seabirds unless management guidelines are developed and enforced. Information shows that tourism in coastal Patagonia is compatible with seabird conservation if appropriately managed. Given the rapid increase in the interest in visiting seabird colonies in Patagonia, several management tools such as sanctuaries, the limitation of visitor numbers and both temporal and spatial zoning, need to be implemented in the short term.