Synthliboramphus Antiquus Research Articles

Amino acid-specific isotopes reveal changing five-dimensional niche segregation in Pacific seabirds over 50 years

Hutchison’s niche theory suggests that coexisting competing species occupy non-overlapping hypervolumes, which are theoretical spaces encompassing more than three dimensions, within an n-dimensional space. The analysis of multiple stable isotopes can be used to test these ideas where each isotope can be considered a dimension of niche space. These hypervolumes may change over time in response to variation in behaviour or habitat, within or among species, consequently changing the niche space itself. Here, we use isotopic values of carbon and nitrogen of ten amino acids, as well as sulphur isotopic values, to produce multi-isotope models to examine niche segregation among an assemblage of five coexisting seabird species (ancient murrelet Synthliboramphus antiquus, double-crested cormorant Phalacrocorax auritus, Leach’s storm-petrel Oceanodrama leucorhoa, rhinoceros auklet Cerorhinca monocerata, pelagic cormorant Phalacrocorax pelagicus) that inhabit coastal British Columbia. When only one or two isotope dimensions were considered, the five species overlapped considerably, but segregation increased in more dimensions, but often in complex ways. Thus, each of the five species occupied their own isotopic hypervolume (niche), but that became apparent only when factoring the increased information from sulphur and amino acid specific isotope values, rather than just relying on proxies of δ15N and δ13C alone. For cormorants, there was reduction of niche size for both species consistent with a decline in their dominant prey, Pacific herring Clupea pallasii, from 1970 to 2006. Consistent with niche theory, cormorant species showed segregation across time, with the double-crested demonstrating a marked change in diet in response to prey shifts in a higher dimensional space. In brief, incorporating multiple isotopes (sulfur, PC1 of δ15N [baselines], PC2 of δ15N [trophic position], PC1 and PC2 of δ13C) metrics allowed us to infer changes and differences in food web topology that were not apparent from classic carbon–nitrogen biplots.

Characterizing Ancient Murrelet Synthliboramphus antiquus movement behaviour during breeding‐season foraging trips using hidden Markov models

Seabird species are increasingly threatened globally due to a range of anthropogenic impacts affecting at‐sea habitat. Characterizing at‐sea movement patterns and identifying foraging behaviour allows researchers to identify critical habitat but can be challenging for small diving species. The Ancient Murrelet Synthliboramphus antiquus is an alcid species of conservation concern in Canada. At‐sea distribution and movements of this species during the breeding season are currently poorly understood. We mounted GPS tracking devices on breeding Ancient Murrelets from two colonies along the southeastern coast of Haida Gwaii, one colony in 2018 and one in 2019, to collect movement data during foraging trips. We used hidden Markov models (HMMs) to identify three movement behaviour states from track characteristics, which we interpreted as transit, resting and foraging. Immersion data collected from the GPS tags allowed us to interpret the two slow‐moving states and to confidently identify foraging movement behaviour. From the 42 individuals tracked we found that foraging trips encompassed large areas of Hecate Strait, to the east of the colonies. Birds nesting on Ramsay Island in 2018 travelled on average 453 km in 4.3 days, up to a mean of 108 km from the colony. Birds breeding on George Island in 2019 took shorter trips, travelling on average 263 km in 3.0 days, and up to 81 km from the colony. In both years, birds spent approximately one‐third of their time in each behaviour state. Resting often took place throughout a whole night at sea; foraging occurred predominately during the day. Transit took place during the night, when birds were leaving or returning to the colony, or during the day, possibly indicating movement between prey patches. Our results can inform marine conservation of this vulnerable species by differentiating foraging from other at‐sea movement behaviours and is a first step to identifying critical foraging habitat.

Temporal trends (1968–2019) of legacy persistent organic pollutants (POPs) in seabird eggs from the northeast Pacific: Is it finally twilight for old POPs?

Legacy persistent organic pollutants (POPs), such as organochlorine pesticides (OCs) and polychlorinated biphenyls (PCBs), are known to persist in the marine environment; however, whether concentrations of these POPs have decreased or stabilized from Canada's Pacific coast in recent years is unclear. Here, we examined temporal trends of various legacy POPs in the eggs of five seabird species; two cormorants (Nannopterum auritum and Urile pelagicus), an auklet (Cerorhinca monocerata), a murrelet (Synthliboramphus antiquus), and a storm-petrel (Hydrobates leucorhous), sampled 1968 to 2019 from 23 colonies along the Pacific coast of British Columbia, Canada. The contaminant profile in the eggs of all species and sampling years was dominated by ΣPCBs, followed by ΣDDT (mostly p,p’-DDE), ΣHCH (β-HCH), ΣCHLOR (oxychlordane), and ΣCBz (HCB). ΣOC and ΣPCB concentrations were generally higher in double-crested cormorant eggs than in the other four species. The majority of legacy POPs are either significantly declining (e.g. p,p’-DDE, HCB, HE, oxychlordane, ΣPCBs) or showing no directional change over time (ΣMirex) in the eggs of our monitoring species. Contaminants such as α-HCH, cis- and trans-chlordane, p,p’-DDT, dieldrin, and octachlorostyrene also showed evidence of downward trends, largely influenced by non-detect values during more recent sampling periods. Increasing trends were observed for β-HCH in the eggs of some species; however, mean concentrations eventually returned to early 2000 levels by the end of the study period. Although bulk δ15N and δ13C egg values varied interannually, compound-specific amino acid analyses suggested no major changes in trophic position or baseline food web signature. Temporal trends observed here were comparable to those found in other seabird species and pelagic food webs. As most legacy POPs in our data set were at very low levels in recent years, we support the general consensus that it is indeed the twilight years for old POPs, and we attribute these declines largely to voluntary regulations and international restrictions on the production and use of these compounds, and thus their release into the marine environment.

Genetic characteristics of a small breeding population of ancient murrelets from Teuri Island, Japan, based on mitochondrial DNA sequences and newly‐developed microsatellite markers

AbstractA small population of ancient murrelets (Synthliboramphus antiquus) nests and breeds on vertical sea cliffs in Teuri Island, Japan. Although this small population is at high risk of extinction, practical conservation plans were not established owing to the lack of basic data, for example, ecological and genetic information. Here, mitochondrial DNA and microsatellite analyses were performed on ancient murrelets collected in the Teuri and Aleutian breeding populations, as well as on wintering individuals in Japan and museum specimens. Mitochondrial DNA analysis revealed that the Teuri population shared haplotypes with the Aleutian population, but not with the British Columbian and the Kamchatka populations from a previous study. Microsatellite analysis revealed high gene flow between the Teuri and Aleutian breeding populations. There was no evidence of loss of genetic diversity in the Teuri population. Museum specimens possessed some unique alleles not found in the more recent samples. Our results suggest that strategies for the conservation of Teuri and Aleutian populations should be managed separately from those designed for breeding populations in the eastern Pacific region, at the very least. For conservation of the Teuri population, we do not recommend captive breeding because of gene flow between Teuri and Aleutian populations, but protection of nesting habitats and monitoring of demographic indexes would be more effective for maintaining their genetic diversity and population size.

Plastic debris ingestion by seabirds on the Korean Peninsula

Plastic ingestion studies in seabirds that analyse the frequency of occurrence and the characteristics of the plastics ingested by each species provide valuable information for marine environmental assessments by quantifying the impacts of marine debris on seabirds. We investigated the frequency of plastic ingestion from a sample of 387 individuals of 11 seabird species on the Korean Peninsula. We found evidence of plastic ingestion in red-breasted mergansers (Mergus serrator) (33.3%), Pacific loons (Gavia pacifica) (10.0%), Swinhoe's storm petrels (Hydrobates monorhis) (93.7%), black-tailed gulls (Larus crassirostris) (12.9%) and ancient murrelets (Synthliboramphus antiquus) (0.9%). In particular, it was observed that Swinhoe's storm petrels had the highest frequency of plastic ingestion, both in terms of the number of affected individuals, and the accumulated mass of plastic debris ingested. The majority of seabirds examined in our study had ingested microplastics, comprised predominantly of user plastics. This is the first report quantifying plastic ingestion in seabirds on the Korean Peninsula and in the broader area of the East Asian Seas.

Breeding Status and Sex Ratio of Ancient Murrelets Captured in the Nocturnal At-Sea Congregation Off Teuri Island, Japan

We examined brood patch development, sex ratios, and morphological traits of 30 Ancient Murrelets Synthliboramphus antiquus captured from the nocturnal at-sea congregation off Teuri Island, Hokkaido, Japan during late May to early June 2016. Molecular sexing determined that 12 of the murrelets were males and 18 were females. The proportions of murrelets with brood patches (an indicator of breeding status) were similar for males (58%) and females (56%). Breeding murrelets were heavier than non-breeding murrelets. Males had deeper bills and longer heads than females, but their weights, wings, culmens, tarsi, bill widths, and skull widths were similar.

Estimating population abundance using counts from an auxiliary population

We develop a new method for estimating population abundance for notoriously difficult to count populations. This is made possible using an easy to count auxiliary population with a known link to the target population under the framework of a layered hidden Markov model. We apply the new methods to estimate the breeding population of an Ancient Murrelet seabird colony, using Ancient Murrelet chicks as an auxiliary population. We compare our results to those of the established survey methodology from the Canadian Wildlife Service (CWS), which similarly shows a decrease in population over 1995 to 2006. Our methods improve upon the CWS survey methods by allowing density differences across sampling sites, and by allowing estimates to be made between CWS survey years.

Influence of overwinter distribution on exposure to persistent organic pollutants (POPs) in seabirds, ancient murrelets (Synthliboramphus antiquus), breeding on the Pacific coast of Canada

Assessing the fate of both legacy and newer persistent organic pollutants (POPs) is an ongoing challenge. Top predators, including seabirds, are effective monitors of POPs because they forage over a range of marine habitats, integrating signals over space and time. However, migration patterns can make unravelling contaminant sources, and potentially assessments of the effectiveness of regulations, challenging if chemicals are acquired at distant sites. In 2014, we fitted geolocators on ancient murrelets (Synthliboramphus antiqueus) at four colonies on the Pacific Coast of Canada to obtain movement data throughout an annual cycle. All birds underwent a post-breeding moult in the Bering Sea. Around one-third then returned to overwinter on the British Columbia (BC) coast while the rest migrated to overwinter in waters along the north Asian coast. Such a stark difference in migration destination provided an opportunity to examine the influence of wintering location on contaminant signals. In summer 2015, we collected blood samples from returned geo-tagged birds and analyzed them for a suite of contaminants, including polybrominated diphenyl ethers (PBDEs), non-PBDE halogenated flame retardants, perfluoroalkyl substances (PFASs), organochlorines, and mercury. Feathers were also collected and analyzed for stable isotopes (δ13C, δ15N, and δ34S). We found no significant differences in blood concentrations of any contaminant between murrelets from the two different overwinter areas, a result that indicates relatively rapid clearance of POPs accumulated during winter. Spatial variation in diet (i.e., δ13C) was associated with both BDE-47 and -99 concentrations. However, individual variation in trophic level had little influence on concentrations of any other examined contaminants. Thus, blood from these murrelets is a good indicator of recent, local contaminants, as most signals appear independent of overwintering location.

Oil spill settlement funds directed to seabird conservation

Settlement funds from catastrophes can generate lasting conservation benefits, if directed appropriately. Such is the case with the Nestucca oil spill which occurred in Washington State in 1988. The spill killed thousands of marine birds and the subsequent litigation settlement awarded 3.3 million dollars for recovery and monitoring of Canadian seabirds, in addition to clean-up costs. Settlement damage funds were directed to eradicate introduced rats from Langara Island, to restore what was formerly the world's largest colony of Ancient Murrelets (Synthliboramphus antiquus). In addition, settlement funds were devoted to establishing an ecosystem-level baseline of seabirds and their marine prey populations on Triangle Island, the largest and most diverse seabird colony in Western Canada. One of the projects tracked breeding Cassin's Auklet (Ptychoramphus aleuticus) and determined that they foraged far away from the colony in search of deep-sea copepods. The results stimulated conservation planners to enlarge a marine protected area which had been proposed to protect marine birds in the region, but policy guidance was lacking. By 2018 policies had evolved, and Canada announced the formation of their first marine National Wildlife Area following a multi-year engagement process with many interested parties. At the same time, Shell Canada relinquished all of their exploratory drilling rights within the area. The settlement funds from a catastrophic oil spill facilitated the recovery of seabirds on Langara Island, the formation of the first marine protected area for wildlife in Canada, and a reduction of future threats from exploratory drilling in an internationally important ecosystem.

Ticks collected from soil/nest litter and live and dead nestlings of migratory seabirds during their breeding season at six uninhabited Islands, Republic of Korea during 2009 and 2014–2017

The 65th Medical Brigade (MED BDE)/Medical Department Activity-Korea (MEDDAC-K), in collaboration with the Migratory Birds Research Center, National Park Research Institute, conducted migratory bird tick-borne disease surveillance at six small, remote, uninhabited islands near the western (Nan Island), southwestern (Chilbal, Gugul, Gaerin, Hong, and Sogugul islands) and southeastern (Hong Island) coastal areas of the Republic of Korea (ROK) during 2009 and from 2014–2017. Ticks were collected from nest soil/litter of the Ancient Murrelet (Synthliboramphus antiquus), Japanese Murrelet (Synthliboramphus wumizusume), Swinhoe’s Storm Petrel (Hydrobates monorhis), Black-tailed Gull (Larus crassirostris), Pacific Swift (Apus pacificus), and Streaked Shearwater (Calonectris leucomelas) using Tullgren funnels. Ticks also were collected from recently dead nestlings of Swinhoe’s Storm Petrel and Black-tailed Gull at Gugul, Sogugul, Gaerin, Nan, and Hong islands, and single ticks were collected from vegetation (tick drag) and a human bitten on Chilbal Island. A total of 1,578 ticks (61 females, 122 males, 290 nymphs, and 1,105 larvae), belonging to four genera and six species, were collected. Ornithodoros capensis (73.00%; 1,152) was the most commonly collected tick on migratory seabirds, followed by Ornithodoros sawaii (26.55%; 420), Ixodes uriae (0.19%; 3), and Ixodes signatus (0.13%, 2). One (0.06%) Haemaphysalis flava was collected by tick drag and one (0.06%) Amblyomma testudinarium was collected while biting one of the survey members. Ornithodoros species were identified morphologically and confirmed using polymerase chain reaction (PCR) techniques. This is the first record of O. sawaii collected from nest soil/litter during the 2017 nesting season of the Pacific Swift and Streaked Shearwater in the ROK.

Present-Day Assemblage of Birds and Mammals in the Islands of Four Mountains, Eastern Aleutians, Alaska

AbstractWe compiled present-day observations and survey data of the avian and mammal fauna in the Islands of Four Mountains, Alaska, which primarily consist of marine-adapted species, to provide insight into the prehistoric fauna found in the archaeological record. We documented 63 bird species, mainly seabirds (67%). The majority (71%) of the estimated number of breeding birds are ledge nesters, predominately murres, and most (68%) spend the majority of their lives in the offshore environment. We lack good estimates for burrow and crevice nesters, which were impacted by and are still recovering from a period of arctic fox farming in the twentieth century. Marine mammals, predominately Steller sea lion, harbor seal, and sea otter, primarily use accessible land as haul-outs and are found in low numbers compared with the rest of the Aleutians. Red fox, the only land mammal, presently only reside on Chuginadak Island. While the present-day fauna is similar to the fauna recorded in the archaeological record, we found no indication of nesting by ancient murrelets and northern fulmars in the Island of Four Mountains, whereas both species were present in midden sites on Carlisle and Chuginadak Islands, with the possibility of prehistoric breeding colonies on Carlisle Island.

Ornithodoros sawaii (Acari: Ixodida: Argasidae) collected from nest soil/litter of Synthliboramphus antiquus, Synthliboramphus wumizusume, and nest soil/litter and nestlings of Hydrobates monorhis on Gugul and Sogugul Islands, Jeollanam Province, Republic of Korea

The 65th Medical Brigade and Medical Department Activity-Korea, in collaboration with the Migratory Birds Research Center, National Park Research Institute, conducted a migratory bird tick-borne disease surveillance program on Gugul and Sogugul Islands, two small, remote, uninhabited islands in southwestern Jeollanam Province, Republic of Korea (ROK) from 2015–2016. Ticks were collected from nest soil/litter of the Ancient Murrelet, Synthliboramphus antiquus, Japanese Murrelet, Synthliboramphus wumizusume, and Swinhoe’s Storm Petrel, Hydrobates monorhis, using Tullgren funnels. A total of 100 Ornithodoros sawaii (25 females, 56 males, 17 nymphs, and 2 larvae) were collected from 2/33 (6.1%) Ancient Murrelet, 3/11 (27.3%) Japanese Murrelet, and 23/94 (24.5%) Swinhoe’s Storm Petrel nest sites. In addition, 3 larvae were collected from Swinhoe’s Storm Petrel nestlings. Ticks were identified morphologically and species determination was confirmed using polymerase chain reaction techniques. This is the first record of O. sawaii collected from nest soil/litter of the Japanese Murrelet during this bird’s nesting season in the ROK.

Ticks (Acari: Ixodida: Ixodidae) collected from nest soil and litter of Synthliboramphus antiquus on Chilbal Island, Jeollanam Province, Republic of Korea, with the first Korean record of Ixodes uriae White

The 65th Medical Brigade and Medical Department Activity-Korea, in collaboration with the Migratory Birds Research Center, National Park Research Institute, conducted a migratory bird tick-borne disease surveillance program on Chilbal Island during 2016. Chilbal Island is a small, remote, uninhabited government-protected island in southwestern Jeollanam Province, Republic of Korea (ROK). Ticks were collected from nest soil and litter of the Ancient Murrelet, Synthliboramphus antiquus, using Tullgren funnels. A total of 4 Ixodes ticks (3 male Ixodes uriae and 1 female Ixodes signatus) were collected. The principal hosts of I. uriae are pelagic birds that have a largely circumpolar distribution. Ixodes signatus parasitizes other migratory birds in coastal areas of western North America and eastern Asia. This is the first report of I. uriae from the ROK.

Post-breeding movements of Ancient Murrelet Synthliboramphus antiquus family groups, subsequent migration of adults and implications for management.

Increased shipping in British Columbia (BC) waters poses risks for marine birds from marine oil spills. Ancient Murrelets (Synthliboramphus antiquus), small marine diving birds of which half of the world’s population breeds in BC, are especially susceptible to oiling immediately after departing from their breeding colonies, as their offspring are flightless, constraining their parents to remain with them. In 2014 we deployed geolocator loggers on Ancient Murrelets at four breeding colonies, two on the east and two on the west coast of Haida Gwaii to investigate patterns of post-breeding dispersal and subsequent migratory movements. Birds from east coast colonies moved south and east after leaving their colonies, remaining in Queen Charlotte Sound and adjacent waters for 4–6 weeks, whereas those from west coast colonies moved steadily north and west, so that they left BC waters earlier than those from east coast colonies. These movements were consistent with being driven by surface currents. In June, all birds moved rapidly to the eastern Aleutians, SE Bering Sea, and waters off Kamchatka, where they probably moulted. In August, most moved north, some passing through Bering Straits into the Chukchi Sea. In October-November some birds returned to waters off western N America (33%) and the remainder carried on westwards to waters off Japan, Korea and NE China. For the former group the movement to the Bering Sea in June constituted a moult migration and, as such, is the first described for an auk. Those birds wintering in Asia began moving east in February and arrived off BC in March, when observations at colonies show that burrow visits begin in Haida Gwaii. Our data suggest that, immediately after colony departure, birds from the east coast colonies (about half the population of Haida Gwaii) are at higher risk from potential oil spills in northern British Columbia waters than those breeding on the west coast.

Ticks collected from Chilbal Island, Jeollanam Province, Republic of Korea, during 2014–2015

The 65th Medical Brigade and Public Health Command District-Korea, in collaboration with the Migratory Birds Center, National Park Research Institute, conducted a migratory bird tick-borne disease surveillance program on Chilbal Island, a small, remote, uninhabited island in southwestern Jeollanam Province, Republic of Korea (ROK), during 2014–2015. Ticks were collected by dragging vegetation and from nest soil and litter of the Ancient Murrelet, Synthliboramphus antiquus, and Swinhoe’s Storm Petrel, Hydrobates monorhis, using Tullgren funnels. A total of 115 ticks belonging to three genera and three species were collected. Ornithodoros sawaii (98.3%, 113 ticks) was the most frequently collected tick species, followed by Ixodes signatus (0.9%, 1 nymph) collected from nest soil and litter, and Haemaphysalis flava (0.9%, 1 male) collected by tick drag.

Ancient Murrelets Molt Flight Feathers After the Precocial Young Become Independent

Abstract Knowledge of timing and pattern of wing molt is important for explanations of post-breeding movements and inland vagrancy in Ancient Murrelets (Synthliboramphus antiquus). Examination of specimens coupled with observations of family groups and recently independent young suggests that chick rearing and wing molt probably occur separately in adults, although it may commence before the last chicks of the season become independent. An adult Ancient Murrelet beached in September 1976 (Alaska Peninsula) and a probable second-year murrelet beached in July 1987 (Oregon) were synchronously molting remiges. Adults in family groups, collected in July 1920 (southeast Alaska) and July 1948 (British Columbia), and observed in July 2009 (British Columbia), were not molting remiges, although an adult observed with a family group on 18 July 1971 (British Columbia) may have commenced molt. Family groups immediately moved offshore from colonies on Langara Island, Haida Gwaii (Queen Charlotte Islands), British Colum...

Impact of a major forest blowdown event on breeding of Ancient Murrelets, <em>Synthliboramphus antiquus</em>, at a colony in Haida Gwaii, British Columbia

In the winter of 2010–2011 a large storm blew down an area of about 18 ha of mature coastal rainforest on East Limestone Island, Haida Gwaii, British Columbia. The area supported part of a breeding colony of Ancient Murrelets (Synthliboramphus antiquus). Observations of the timing of chick departures from this section of the colony in 2012 and 2013 suggested that daily timing of chick departures were delayed, on average, by about 30 min, compared with earlier years. This delay may have been caused by debris from the blowdown impeding the progress of chicks over the ground. A sharp decrease in the number of chicks leaving the blowdown area in 2014 may signify that some breeding pairs left the area following reduced breeding success.

<p align="left"><strong><em>Ornithodoros sawaii </em></strong><strong>Kitaoka and Suzuki<em> </em>(Acari: Ixodida: Argasidae) collected from nest soil and litter of <em>Synthliboramphus</em> <em>antiquus</em> and </strong><strong><em>Hydrobates</em></strong><strong><em> </em></strong><strong><em>monorhis</em></strong><strong>,</strong> <strong>on Chilbal </strong><strong>I</strong><strong>sland, southwestern Jeollanam Province, Republic of Korea </strong></p>

The 65 th Medical Brigade and Public Health Command Region-Pacific (Korea), in collaboration with the Migratory Birds Center, National Park Research Institute, conducted a migratory bird tick-borne disease surveillance program on Chilbal Island, a small, remote, uninhabited island in southwestern Jeollanam Province, Republic of Korea (ROK), on 1 and 31 May and 15 September 2014. Ticks were collected from nesting soil and litter of the Ancient Murrelet, Synthliboramphus antiquus , and Swinhoe’s Storm Petrel, Hydrobates monorhis , using Tullgren funnels. A total of 12 Ornithodoros sawaii (2 females, 4 males, and 6 nymphs) were collected from 3/36 (8.3%) S. antiquus and 6/20 (30.0%) H. monorhis nest sites. Ticks were identified morphologically and species determination was confirmed using polymerase chain reaction techniques. This is the first report of the genus O rnithodoros and species O. sawaii from the ROK.

First evidence of east-west migration across the North Pacific in a marine bird

Many marine birds undertake long migrations between breeding and wintering areas, including some species that undertake long-distance east–west or west–east movements across many degrees of longitude. To date, however, no east–west migrations have been described across the North Pacific. Geolocators were deployed on Ancient Murrelets Synthliboramphus antiquus breeding in Haida Gwaii, British Columbia, in 2013 and four were retrieved the following year. Longitude positions showed that all four moved rapidly westwards after breeding, three of them reaching waters between Japan and China by November and this location was also supported by ringing data. Return migration was rapid, beginning in February and reaching Haida Gwaii in March, providing the first evidence for bird migration spanning the entire width of the North Pacific. This is the longest migration recorded in any of the Alcidae.

Temporal trends of perfluoroalkyl substances (PFAS) in eggs of coastal and offshore birds: Increasing PFAS levels associated with offshore bird species breeding on the Pacific coast of Canada and wintering near Asia.

Perfluoroalkyl substances (PFAS) such as perfluoroalkyl carboxylates (PFCAs) and perfluoroalkyl sulfonates (PFSAs) have become virtually ubiquitous throughout the environment, and, based on laboratory studies, have known toxicological consequences. Various national and international voluntary phase-outs and restrictions on these compounds have been implemented over the last 10 to 15 years. In the present study, we examine trends (1990/1991-2010/2011) in aquatic birds (ancient murrelet, Synthliboramphus antiquus [2009 only]; Leach's storm-petrels, Oceanodroma leucorhoa; rhinoceros auklets, Cerorhinca monocerata; double-crested cormorants, Phalacrocorax auritus; and great blue herons, Ardea herodias). The PFCA, PFSA, and stable isotope (δ(15) N and δ(13) C) data collected from these species from the Pacific coast of Canada, ranging over 20 to 30 years, were used to investigate temporal changes in PFAS coupled to dietary changes. Perfluorooctane sulfonic acid (PFOS), the dominant PFSA compound in all 4 species, increased and subsequently decreased in auklet and cormorant eggs in line with the manufacturing phase-out of PFOS and perfluorooctanoic acid (PFOA), but concentrations continuously increased in petrel eggs and remained largely unchanged in heron eggs. Dominant PFCA compounds varied between the offshore and coastal species, with increases seen in the offshore species and little or variable changes seen in the coastal species. Little temporal change was seen in stable isotope values, indicating that diet alone is not driving observed PFAS concentrations.