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Like many wildlife species of management concern, the western snowy plover Charadrius nivosus nivosus is the subject of intensive population monitoring. However, intensive monitoring of reproductive success for this shorebird is time-consuming, financially costly, and potentially disruptive to the birds of interest. These constraints mean that intensive monitoring is not feasible throughout the range of the federally threatened Pacific Coast population. In this study, we used data collected from one intensively monitored subpopulation to assess how reductions in monitoring effort (number of chicks individually marked) would affect the accuracy of estimates of fledging success for western snowy plover chicks. We used monitoring data collected on chicks hatching at 1,845 nests from 2003 to 2012 as a theoretical subpopulation from which to draw random samples for this assessment. As expected, we found that accuracy (as measured by the inverse of percentage difference between sampled and actual fledge rates) increased with increasing percentage of the subpopulation monitored each year. We also found that the day of the week that chicks hatched and were banded had no effect on fledging success. Thus, reducing monitoring effort by banding chicks on specific days of the week is one suitable method for subpopulation sampling that has no embedded biases in the subsequent estimate of fledging success. The results of our analyses provide estimates of the accuracy of different sampling schemes, which should help managers of this threatened shorebird assess appropriate monitoring methods. We recommend use of our methods for others interested in assessing accuracy of sampling schemes for reproductive success of western snowy plover or other birds with similar life-history traits.

There is ongoing public debate about the best course of action to take when wildlife are affected by oil spills. Critics of wildlife rehabilitation suggest that the cleaning and release of oiled animals is a waste of resources focused on individual animals (not populations); thus, the most responsible course of action is to immediately euthanize affected animals. These critics claim that survival of rehabilitated animals is poor, and that the funds spent on rehabilitation would benefit wildlife more if spent on other conservation efforts. In this opinion piece, with a focus on birds, we review reasons for engaging in a coordinated response to oiled wildlife that includes cleaning and rehabilitation. The reasons for responding to oiled wildlife in any capacity include ethical, human safety, and legal aspects. Our rationale for proposing that responders attempt to rehabilitate wildlife, rather than planning on immediate euthanasia, includes financial, scientific, and additional ethical reasons. Financially, costs for wildlife rehabilitation are typically a very small portion of overall oil-spill response costs, and are typically independent of postspill enforcement and funds used to restore injured natural resources. Scientifically, we review recent studies that have shown that animals cleaned and rehabilitated after oil spills can often survive as well as nonoiled control animals. Ethically, some people would consider individual animals to have intrinsic value and that we, as consumers of petroleum products, have an obligation to reduce suffering and mitigate injuries associated with such accidents. For these reasons, we suggest that, although humane euthanasia should always be considered as an option for animals unlikely to return to normal function after rehabilitation, response to oil spills should include a coordinated effort to attempt wildlife rehabilitation.

From August through December 2015, beachcast bird survey programs reported increased deposition of Common Murres ( Uria aalge) on central and northern California beaches, but not on southern California beaches. Coastal wildlife rehabilitation centers received more than 1,000 live, stranded, and debilitated murres from Sonoma County to San Luis Obispo County during August-October. Approximately two-thirds of admitted birds were after-hatch-year birds in emaciated body condition and in various stages of molt, with extremely worn plumage. Necropsies were done on a sample ( n=35) of birds to determine the probable cause of death of beachcast carcasses. Most birds examined during necropsy were emaciated, with starvation the most likely cause of death. Birds were also tested for underlying infectious diseases at the US Geological Survey National Wildlife Health Center and harmful algal bloom toxins at the University of California at Santa Cruz and the National Oceanographic and Atmospheric Administration's Northwest Fisheries Science Center. Twenty-four out of 29 tested birds had detectable levels of domoic acid, and no indication of infectious disease was found. Emaciation is thought to be the cause of death for these birds, with a large warm water anomaly and harmful algal bloom playing a secondary detrimental role.

Effectiveness of rehabilitating wildlife following oil spills has been controversial. Impacts include mortality or changes in behavior affecting health or reproduction. Immediately following a bunker fuel oil spill on San Francisco Bay, California, USA, a unique experiment was conducted to examine the movement and foraging behavior of Surf Scoters (Melanitta perspicillata) that had been oiled, captured, cleaned, rehabilitated, and radio-marked. Unoiled Surf Scoters were similarly cleaned, rehabilitated, and radio-marked while other unoiled Surf Scoters were radio-marked as controls. Surf Scoters in the control group had larger home-ranges (46.29 ± 3.23 km2) than either the oiled/rehabilitated (32.58 ± 5.48 km2) or rehabilitated only groups (31.06 ± 3.05 km2); the control group also was more likely to use unsheltered, shallow areas of the bay (66.9 ± 4.3% of locations) than either the oiled/rehabilitated (50.3 ± 5.2%) or rehabilitated only groups (58.2 ± 6.5%). The oiled/rehabilitated group was closer to shore (986 ± 149 m) than rehabilitated (1,894 ± 295 m) or control groups (2,113 ± 227 m). Differences in habitat use, movement patterns, and home range sizes indicated that Surf Scoters held in captivity were more restricted in their movements; therefore, captivity and rehabilitation practices may also influence success of the rehabilitation.

Species that undergo simultaneous flight-feather molt are susceptible to mortality during the flightless period. Remigial molt was examined in non-breeding Western Grebes (Aechmophorus occidentalis) and Clark's Grebes (A. clarkii) using beachcast carcasses from California to Washington to determine wrhere and when molt occurs and help identify regions of maximum risk. Molt occurred in 18% of individuals and in all age classes and months examined, including winter, not previously recognized as a significant period for Western and Clark's grebe molt. Molt was encountered in all regions, with the highest proportions in Oregon/Washington during fall (35%), and central (18%) and southern (17%) California during winter. The percentage of Western and Clark's grebes in molt collected during the first 3 days of an oil spill was greater than later in the response (27% vs. 12%), suggesting a greater vulnerability to oiling during this part of their life cycle. Oil spills and other mortality events can prov...

Captive-breeding and -rearing programs have been widely used for the conservation and recovery of imperiled species, and the success of such programs should be rigorously evalu- ated. In this study, we assessed the success of captive-rearing for a threatened shorebird, the snowy plover Charadrius nivosus, by comparing the survival and reproductive success of captive- reared and wild-reared individuals on the central California coast from 2001 to 2010. We used mark-recapture analysis, implemented in the program MARK, to estimate apparent annual sur- vival (ϕ) and encounter occasion detection probability (p) from capture and sighting data of marked plovers. We compared 3 measures of reproductive success (hatch rate, fledge rate and juveniles fledged per year) using stratified randomization tests based on individual breeding his- tories where captive- and wild-reared plovers were matched for age, sex and year. Captive- and wild-reared snowy plovers had similar apparent survival and reproductive rates and paired with mates of similar age in their first breeding year. The only exception was that captive males after their first breeding year had lower fledging rates than males from the overall population, but this did not affect the annual productivity rate. We conclude that releasing captive-reared individuals is a valuable part of ongoing efforts to restore the snowy plover population in California, and is also useful in cases where plover nests may need to be salvaged to protect them from oil contam- ination or other catastrophic events.

Birds are often the most numerous vertebrates damaged and rehabilitated in marine oil spills; however, the efficacy of avian rehabilitation is frequently debated and rarely examined experimentally. We compared survival of three radio-marked treatment groups, oiled, rehabilitated (ORHB), un-oiled, rehabilitated (RHB), and un-oiled, non-rehabilitated (CON), in an experimental approach to examine post-release survival of surf scoters (Melanitta perspicillata) following the 2007 M/V Cosco Busan spill in San Francisco Bay. Live encounter-dead recovery modeling indicated that survival differed among treatment groups and over time since release. The survival estimate (±SE) for ORHB was 0.143 ± 0.107 compared to CON (0.498 ± 0.168) and RHB groups (0.772 ± 0.229), suggesting scoters tolerated the rehabilitation process itself well, but oiling resulted in markedly lower survival. Future efforts to understand the physiological effects of oil type and severity on scoters are needed to improve post-release survival of this species.

Sea otters ( Enhydra lutris ) have exceptionally high energetic requirements, which nearly double during lactation and pup care. Thus, females are extremely vulnerable to caloric insufficiency. Despite a number of compensatory strategies, the metabolic challenge of reproduction culminates in numerous maternal deaths annually. Massive depletion of energy reserves results in a case presentation that we define as end-lactation syndrome (ELS), characterized by moderate to severe emaciation not attributable to a concurrent, independent disease process in females dying during late pup care or postweaning. We compiled detailed data for 108 adult female southern sea otters ( Enhydra lutris nereis) examined postmortem that stranded in California, US, 2005-12, and assessed pathology, reproductive status, and the location and timing of stranding. We introduce simple, grossly apparent, standardized physical criteria to assess reproductive stage for female sea otters. We also describe ELS, examine associated risk factors, and highlight female life history strategies that likely optimize reproduction and survival. Our data suggest that females can reset both the timing and energetic demands of reproduction through fetal loss, pup abandonment, or early weaning as part of specific physiologic checkpoints during each reproductive cycle. Females appear to preload nutritionally during delayed implantation and gestation to increase fitness and reproductive success. We found that ELS was a major cause of death, affecting 56% of enrolled adult females. Peak ELS prevalence occurred in late spring, possibly reflecting the population trend toward fall/winter pupping. Increasing age and number of pregnancies were associated with a higher risk of ELS. Although the proportion of ELS females was highest in areas with dense sea otter populations, cases were recovered throughout the range, suggesting that death from ELS is associated with, but not solely caused by, population resource limitation.

Patterns of spatial and temporal co-occurrence or avoidance among different species of marine birds and mammals can provide insights into the degree to which these top predators com- pete for prey. I conducted at-sea surveys in nearshore waters of Monterey Bay, California, USA, and used a randomization technique to assess co-occurrence patterns of marine birds and mammals in 1 km transect segments. As expected, strongest positive associations were among members of 3 dif- ferent foraging guilds: pursuit-divers, surface-feeders, and plunge-divers. Within guilds, pursuit- divers exhibited marked avoidance of one another (negative co-occurrence), although surface- feeders often co-occurred with each other. The study was conducted during 2 yr, 1999 and 2000; during 2000, when predator abundance was greater and prey abundance may have been decreased, pursuit-divers exhibited more avoidance of one another than in 1999. These data suggest that com- petition reduces foraging ability for pursuit-diving species, making it more profitable for them to dis- perse more widely, whereas surface-feeding species (primarily gulls) benefit from flock foraging under most conditions. Larger animals tended to frequently co-occur, while the smallest member of each guild tended to avoid other species, indicating competitive exclusion of smaller predators.

In this study, the relationship between physical attributes of sandy beaches, levels of human disturbance, and shorebird occurrence was investigated. The linear density km-1 of shorebirds on 42 km of sandy beaches in Monterey Bay, California was documented from late autumn through spring, and the relationship of shorebird densities to two physical variables (slope of beach swash zone, total beach width), one spatial variable (distance to Elkhorn Slough, a wetland of regional importance for shorebirds), and relative level of human disturbance was analyzed using stepwise multiple regression. The six most abundant species were Sanderling (Calidris alba), Willet (Tringa semipalmata), Marbled Godwit (Limosa fedoa), Black-bellied Plover (Pluvialis squatarola), Whimbrel (Numenius phaeopus) and Snowy Plover (Charadrius alexandrinus). Mean abundance of four of the six most abundant species (Marbled Godwit, Willet, Whimbrel, Black-bellied Plover) was negatively related to swash zone slope; flatter beaches ...

Breeding seabirds have been well studied but seabird ecology during the nonbreeding season is poorly understood because many species disperse far from breeding colonies to molt at sea. We characterized the timing of prebasic molt and postbreeding dispersal, described postbreeding dispersal movements, and estimated changes in body mass during molt for Marbled Murrelets (Brachyramphus marmoratus; Alcidae) in central California, 1999–2004. According to mark–recapture and at-sea surveys, 248–315 of 496–637 individuals (43–50%) used Ano Nuevo Bay, located immediately adjacent to nesting areas, for their prebasic molt in August–October. Long-distance dispersal (≥ 100 km) from Ano Nuevo Bay by radiomarked Marbled Murrelets was low during breeding (9–13%, n = 46), but was greater for individuals radiomarked at the end of the breeding season (69–90%, n = 20). The mean dispersal dates were 18 May and 21 October for the breeding and postbreeding samples, respectively, and postbreeding dispersal occurred an ...

The distribution of marine birds relative to water clarity was examined in the nearshore waters of Monterey Bay, California. I conducted nine at-sea surveys in 1999 and 2000 and simultaneously recorded water clarity and the density of five taxa of marine birds. Among plunge-divers, Forster's Terns (Sterna forsten) occurred more frequently than expected over turbid water ( 5 m Secchi depth). Turbidity in Monterey Bay may be caused by suspended organic matter, including phytoplankton, during summer and fall. Forster's Tern may prefer such areas because small fish are likely to occur near this potential food source. Brandt's Cormorants probably rely on vision to catch fish near the bottom and turbid water may reduce available light and limit visual acuity. The distribution of Brown Pelicans (Pelecanus occidentalis), Western/Clark's Grebes (Aechmophorus occidentalis!clarki?), and Marbled Murrelets (Brachyramphus marmoratus) did not appear to be influenced by turbidity levels, indicating that some seabirds use marine habitats with a wide range of water clarities.

Radio-telemetry was used to continuously monitor the at-sea activity of an adult Marbled Murrelet (Brachyramphus marmoratus) nesting in Santa Cruz County, California. From 05.39 h on 28 May 1997, to 05.14 h on 29 May 1997, the murrelet was followed by tracking teams at Ano Nuevo Bay. Between 05.44 h and 20.19 h on 28 May, the bird engaged in eleven dive bouts, with a mean duration of 18.8 ± 5.4 min. Mean dive duration was 24.8 ± 15.7 s; mean surface between dives was 15.2 ± 12.7 s. No dives were initiated after 20.19 h. The bird spent 12.3% of the at-sea period and 23.4% of daylight hours engaged in diving bouts. This relatively small amount of time spent diving allows for considerable flexibility in activity budget.

We assessed temporal and spatial patterns of chronic oiling of seabirds in California during 2005–2010, using data on: (1) live oiled birds reported to the Oiled Wildlife Care Network (OWCN) from throughout the state, and (2) dead oiled birds found during systematic monthly beached-bird surveys in central California. A mean of 245 (±141 SD) live miscellaneous oiled birds (not associated with known oil spills) were reported to the OWCN per year, and 0.1 oiled dead birds km−1 per month were found on beach surveys in central California. Chemical fingerprinting of oiled feathers from a subset of these birds (n = 101) indicated that 89% of samples tested were likely from natural petroleum seeps off southern and central California. There was a pronounced peak during late winter in the number of oiled birds reported in southern California, which we theorize may be related to large storm waves disturbing underwater seeps.

Following the spill of bunker oil from the M/V Cosco Busan into San Francisco Bay, California on 7 November 2007, we evaluated the foraging characteristics, survival and movements of surf scoters (Melanitta perspicillata) that had been rehabilitated following formal rehabilitation protocols through the use of intracoelomic implants of radio transmitters and aerial/land based tracking. We compared these behavioral attributes of oiled surf scoters to surf scoters that were not oiled, but instead captured and released or put through the same rehabilitation procedure (thus separating the rehabilitation/captivity effects from the oiling). Initial behavioral observations have shown that mean home range size was greatest for unrehabilitated birds, and oiled birds were observed closer to shore than either the un-oiled rehabilitated or control group. Survival was also seen to differ among treatment groups and over encounter occasions, with cumulative winter survival estimates being lowest for oiled birds ...

Habitat use, diet and breeding biology of tufted puffins (Fratercula cirrhata) were studied in Prince William Sound, Alaska, during summer 1995. On Seal Island, 112 puffin bur- rows (71% active) were located. Of 95 accessible burrows, 49% were typical earthen burrows, whereas the remainder were atypical for the species (e.g., under tree roots). Hatching success ('79%), fledging success (282%), chick growth rates (17.7 g/day), asymptotic (600 g) and fledg- ing (563 g) weights, meal sizes (14.2 g), meal delivery rates (5.32 meals/day), and daily rations (75.5 g/day) were all average or above-average for tufted puffins in Alaska. A total of 42 chick meals, comprising 125 individual prey were collected. Meals were composed of juvenile pollock (12.7% of total mass), herring (21.8%), prowfish (32.3%), salmonids (24.1%), and capelin, sand- lance and squid (